RING finger (Really Interesting New Gene) domain and U-box domain superfamily; The RING finger is a specialized type of Zn-finger of 40 to 60 residues that binds two atoms of zinc. It is defined by the "cross-brace" motif that chelates zinc atoms by eight amino acid residues, typically Cys or His, arranged in a characteristic spacing. Canonical RING motifs have been categorized into two major subclasses, RING-HC (C3HC4-type) and RING-H2 (C3H2C3-type), according to their Cys/His content. There are also many variants of RING fingers: some have different Cys/His patterns while some lack a single Cys or His residue at typical Zn ligand positions (the fourth or eighth zinc ligand is prevalently exchanged for an Asp, which can indeed chelate Zn in a RING finger as well). C4C4-, C3HC3D-, C2H2C4-, and C3HC5-type RING fingers are closely related to RING-HC fingers. In contrast, C4HC3- (RING-CH alias RINGv), C3H3C2-, C3H2C2D-, C3DHC3-, and C4HC2H-type RING fingers are more closely related to RING-H2 fingers. However, not all RING finger-containing proteins display regular RING finger features, and the RING finger family has turned out to be multifarious. The degenerate RING fingers of the Siz/PIAS RING (SP-RING) family proteins and sporulation protein RMD5, are characterized by lacking the second, fifth, and sixth Zn2+ ion-coordinating residues. They bind only one Zn2+ ion. On the other hand, the RING fingers of the human APC11 and RBX1 proteins can bind a third Zn atom since they harbor four additional Zn ligands. U-box is a modified form of the RING finger domain that lacks metal chelating Cys and His residues. It resembles the cross-brace RING structure consisting of three beta-sheets and a single alpha-helix, which would be stabilized by salt bridges instead of chelated metal ions. U-box proteins are widely distributed among eukaryotic organisms and show a higher prevalence in plants than in other organisms. RING finger/U-box-containing proteins are a group of diverse proteins with a variety of cellular functions, including oncogenesis, development, viral replication, signal transduction, the cell cycle and apoptosis. Many of them are ubiquitin-protein ligases (E3s) that serve as scaffolds for binding to ubiquitin-conjugating enzymes (E2s, also referred to as ubiquitin carrier proteins or UBCs) in close proximity to substrate proteins, which enable efficient transfer of ubiquitin from E2 to the substrates.

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                ....*....|....*....|....*....|....*....|....*....|.
gi 18424150 144 CGICMEMNSKV-----VLPNCTHSLCIKCYRDWRGRSQ-------SCPFCR 182
Cdd:cd16521   3 CGICMEVVLEKerrfgILSNCNHVFCLECIREWRSSKDfensivrSCPICR 53

RING finger, HC subclass, found in the makorin (MKRN) proteins; The MKRN protein subfamily includes ribonucleoproteins that are characterized by a variety of zinc-finger motifs, including typical arrays of one to four C3H1-type zinc fingers and a C3HC4-type RING-HC finger. Another motif rich in Cys and His residues (CH), with so far unknown function, is also generally present in MKRN proteins. MKRN proteins may have E3 ubiquitin ligase activity.

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                ....*....|....*....|....*....|....*....|....*....|.
gi 18424150 144 CGICMEMNSKV-----VLPNCTHSLCIKCYRDWRGRSQ-------SCPFCR 182
Cdd:cd16521   3 CGICMEVVLEKerrfgILSNCNHVFCLECIREWRSSKDfensivrSCPICR 53

Ring finger domain;

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                  ....*....|....*....|....*....|....*....|..
gi 18424150   144 CGICMEM---NSKVVLPNCTHSLCIKCYRDWRGRSQSCPFCR 182
Cdd:pfam13639   3 CPICLEEfeeGDKVVVLPCGHHFHRECLDKWLRSSNTCPLCR 44

RING-finger-containing E3 ubiquitin ligase [Signal transduction mechanisms];

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                ....*....|....*....|....*....|....*....|....*....|....*
gi 18424150 144 CGICMEMNSKVVLPNCTHSLCIKCYRDWRGRSQSCPFCR----DSLKRVDSGDLW 194
Cdd:COG5432  28 CRICDCRISIPCETTCGHTFCSLCIRRHLGTQPFCPVCRedpcESRLRGSSGSRE 82

RING finger, HC subclass, found in the makorin (MKRN) proteins; The MKRN protein subfamily includes ribonucleoproteins that are characterized by a variety of zinc-finger motifs, including typical arrays of one to four C3H1-type zinc fingers and a C3HC4-type RING-HC finger. Another motif rich in Cys and His residues (CH), with so far unknown function, is also generally present in MKRN proteins. MKRN proteins may have E3 ubiquitin ligase activity.

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                ....*....|....*....|....*....|....*....|....*....|.
gi 18424150 144 CGICMEMNSKV-----VLPNCTHSLCIKCYRDWRGRSQ-------SCPFCR 182
Cdd:cd16521   3 CGICMEVVLEKerrfgILSNCNHVFCLECIREWRSSKDfensivrSCPICR 53

RING finger, HC subclass, found in RING finger protein 8 (RNF8) and similar proteins; RNF8 is a telomere-associated E3 ubiquitin-protein ligase that plays an important role in DNA double-strand break (DSB) repair via histone ubiquitination. It is localized in the nucleus and interacts with class III E2s (UBE2E2, UbcH6, and UBE2E3), but not with other E2s (UbcH5, UbcH7, UbcH10, hCdc34, and hBendless). It recruits UBC13 for lysine 63-based self polyubiquitylation. Its deficiency causes neuronal pathology and cognitive decline, and its loss results in neuron degeneration. RNF8, together with RNF168, catalyzes a series of ubiquitylation events on substrates such as H2A and H2AX, with the H2AK13/15 ubiquitylation being particularly important for recruitment of repair factors p53-binding protein 1 (53BP1) or the RAP80-BRCA1 complex to sites of DSBs. RNF8 mediates the ubiquitination of gammaH2AX, and recruits 53BP1 and BRCA1 to DNA damage sites which promotes DNA damage response (DDR) and inhibits chromosomal instability. Moreover, RNF8 interacts with retinoid X receptor alpha (RXR alpha) and enhances its transcription-stimulating activity. It also regulates the rate of exit from mitosis and cytokinesis. RNF8 contains an N-terminal forkhead-associated (FHA) domain and a C-terminal C3HC4-type RING-HC finger.

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                ....*....|....*....|....*....|....*....|...
gi 18424150 144 CGICMEMNSKVVLPNCTHSLCIKCYRDWRGRSQSCPFCRDSLK 186
Cdd:cd16535   4 CSICSELFIEAVTLNCSHSFCSYCITEWMKRKKECPICRKPIT 46

N1R/p28-like protein; Provisional

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                 ....*....|....*....|....*....|....*....|....*..
gi 18424150  144 CGICME------MNSKV--VLPNCTHSLCIKCYRDWRGRSQSCPFCR 182
Cdd:PHA02929 177 CAICMEkvydkeIKNMYfgILSNCNHVFCIECIDIWKKEKNTCPVCR 223

HC subclass of RING (RING-HC) finger and its variants; The RING finger is a specialized type of Zn-finger of 40 to 60 residues that binds two atoms of zinc. It is defined by the "cross-brace" motif that chelates zinc atoms by eight amino acid residues, typically Cys or His, arranged in a characteristic spacing. Canonical RING motifs have been categorized into two major subclasses, RING-HC (C3HC4-type) and RING-H2 (C3H2C3-type), according to their Cys/His content. There are also many variants of RING fingers. Some have a different Cys/His pattern. Some lack a single Cys or His residue at typical Zn ligand positions, especially, the fourth or eighth zinc ligand is prevalently exchanged for an Asp, which can chelate Zn in a RING finger as well. This family corresponds to the HC subclass of RING (RING-HC) fingers that are characterized by containing C3HC4-type canonical RING-HC fingers or noncanonical RING-HC finger variants, including C4C4-, C3HC3D-, C2H2C4-, and C3HC5-type modified RING-HC fingers. The canonical RING-HC finger has been defined as C-X2-C-X(9-39)-C-X(1-3)-H-X(2-3)-C-X2-C-X(4-48)-C-X2-C. It binds two Zn ions in a unique "cross-brace" arrangement, which distinguishes it from tandem zinc fingers and other similar motifs. RING-HC fingers can be found in a group of diverse proteins with a variety of cellular functions, including oncogenesis, development, viral replication, signal transduction, the cell cycle, and apoptosis. Many of them are ubiquitin-protein ligases (E3s) that serve as scaffolds for binding to ubiquitin-conjugating enzymes (E2s, also referred to as ubiquitin carrier proteins or UBCs) in close proximity to substrate proteins, which enables efficient transfer of ubiquitin from E2 to the substrates.

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                ....*....|....*....|....*....|....*....
gi 18424150 144 CGICMEMNSKVVLPNCTHSLCIKCYRDW-RGRSQSCPFC 181
Cdd:cd16449   3 CPICLERLKDPVLLPCGHVFCRECIRRLlESGSIKCPIC 41

RING finger, HC subclass, found in topoisomerase I-binding arginine/serine-rich protein (Topors) and similar proteins; Topors, also known as topoisomerase I-binding RING finger protein, tumor suppressor p53- binding protein 3, or p53-binding protein 3 (p53BP3), is a ubiquitously expressed nuclear E3 ubiquitin-protein ligase that can ligate both ubiquitin and small ubiquitin-like modifier (SUMO) to substrate proteins in the nucleus. It contains an N-terminal C3HC4-type RING-HC finger which ligates ubiquitin to its target proteins including DNA topoisomerase I, p53, NKX3.1, H2AX, and the AAV-2 Rep78/68 proteins. As a RING-dependent E3 ubiquitin ligase, Topors works with the E2 enzymes UbcH5a, UbcH5c, and UbcH6, but not with UbcH7, CDC34, or UbcH2b. Topors acts as a tumor suppressor in various malignancies. It regulates p53 modification, suggesting it may be responsible for astrocyte elevated gene-1 (AEG-1, also known as metadherin, or LYRIC) ubiquitin modification. Plk1-mediated phosphorylation of Topors inhibits Topors-mediated sumoylation of p53, whereas p53 ubiquitination is enhanced, leading to p53 degradation. It also functions as a negative regulator of the prostate tumor suppressor NKX3.1. Moreover, Topors is associated with promyelocytic leukemia nuclear bodies, and may be involved in the cellular response to camptothecin. It also plays a key role in the turnover of H2AX protein, discriminating the type of DNA damaging stress. Furthermore, Topors is a cilia-centrosomal protein associated with autosomal dominant retinal degeneration. Mutations in TOPORS cause autosomal dominant retinitis pigmentosa (adRP).

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                ....*....|....*....|....*....|....*....|.
gi 18424150 144 CGICMEM--NSKVVLPNCTHSLCIKCYRDWRGRSQSCPFCR 182
Cdd:cd16574   4 CPICLDRfeNEKAFLDGCFHAFCFTCILEWSKVKNECPLCK 44

RING finger, HC subclass, found in makorin-4 (MKRN4) and similar proteins; MKRN4, also known as makorin RING finger protein pseudogene 4, makorin RING finger protein pseudogene 5, RING finger protein 64 (RNF64), zinc finger protein 127-Xp (ZNF127-Xp), or zinc finger protein 127-like 1, is a new divergent member of the makorin protein family in vertebrates. It may have an ancestral gonad-specific function and maternal embryonic expression before duplication in vertebrates. MKRN4 contains typical arrays of one to four C3H1-type zinc fingers, a motif rich in Cys and His residues (CH) and a C3HC4-type RING-HC finger. The RING-HC finger of mammalian MKRN4 shows high sequence similarity with that of MKRN3, and is not included in this model.

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                ....*....|....*....|....*....|....*....|....*....|....*
gi 18424150 144 CGICMEMNSKV---------VLPNCTHSLCIKCYRDWRGRS-------QSCPFCR 182
Cdd:cd16732   4 CGICMDKVYEKahakervfgILPNCNHAFCVGCIKKWRKSKdfqneviKACPQCR 58

RING finger, HC subclass, found in Casitas B-lineage lymphoma (Cbl) proteins; The Cbl adaptor protein family contains a small class of RING-type E3 ubiquitin ligases with oncogenic activity, which is represented by three mammalian members, c-Cbl, Cbl-b and Cbl-c, as well as two invertebrate Cbl-family proteins, D-Cbl in Drosophila and Sli-1 in C. elegans. Cbl proteins function as potent negative regulators of various signaling cascades in a wide range of cell types. They play roles in ubiquitinating activated tyrosine kinases and targeting them for degradation. D-Cbl associates with the Drosophila epidermal growth factor receptor (EGFR) and overexpression of D-Cbl in the eye of Drosophila embryos inhibits EGFR-dependent photoreceptor cell development. Sli-1 is a negative regulator of the Let-23 receptor tyrosine kinase, an EGFR homolog, in vulva development. Cbl proteins in this subfamily consist of a highly conserved N-terminal half that includes a tyrosine-kinase-binding domain (TKB, also known as the phosphotyrosine binding PTB domain, composed of a four helix-bundle, a Ca2+ binding EF-hand and a highly variant SH2 domain) and a C3HC4-type RING-HC finger, both of which are required for Cbl-mediated downregulation of RTKs, and a divergent C-terminal region.

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                ....*....|....*....|....*....|....*....|
gi 18424150 144 CGICMEMNSKVVLPNCTHSLCIKCYRDWR-GRSQSCPFCR 182
Cdd:cd16502   4 CKICAENDKDVRIEPCGHLLCTPCLTSWQdSDGQTCPFCR 43

RING finger, HC subclass, found in tripartite motif-containing protein TRIM65 and similar proteins; TRIM65 is an E3 ubiquitin-protein ligase that interacts with the innate immune receptor MDA5, enhancing its ability to stimulate interferon-beta signaling. It functions as a potential oncogenic protein that negatively regulates p53 through ubiquitination, providing insight into the development of novel approaches targeting TRIM65 for non-small cell lung carcinoma (NSCLC) treatment, and also overcoming chemotherapy resistance. Moreover, TRIM65 negatively regulates microRNA-driven suppression of mRNA translation by targeting TNRC6 proteins for ubiquitination and degradation. TRIM65 belongs to the C-IV subclass of the TRIM (tripartite motif) family of proteins that are defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, Bbox1 and Bbox2, and a coiled coil region, as well as a B30.2/SPRY (SplA and ryanodine receptor) domain positioned C-terminal to the RBCC domain.

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                ....*....|....*....|....*....|....*....|....*
gi 18424150 144 CGICMEM-NSKVVLPnCTHSLCIKCYRDW----RGRSQSCPFCRD 183
Cdd:cd16609   6 CSICLGLyQDPVTLP-CQHSFCRACIEDHwrqkDEGSFSCPECRA 49

RING finger, H2 subclass, found in synoviolin and similar proteins; Synoviolin, also known as synovial apoptosis inhibitor 1 (Syvn1), Hrd1, or Der3, is an endoplasmic reticulum (ER)-anchoring E3 ubiquitin ligase that functions as a suppressor of ER stress-induced apoptosis and plays a role in homeostasis maintenance. It also targets tumor suppressor gene p53 for proteasomal degradation, suggesting crosstalk between ER associated degradation (ERAD) and p53 mediated apoptotic pathway under ER stress. Moreover, synoviolin controls body weight and mitochondrial biogenesis through negative regulation of the thermogenic coactivator peroxisome proliferator-activated receptor coactivator (PGC)-1beta. It upregulates amyloid beta production by targeting a negative regulator of gamma-secretase, Retention in endoplasmic reticulum 1 (Rer1), for degradation. It is also involved in the degradation of endogenous immature nicastrin, and affects amyloid beta-protein generation. Moreover, synoviolin is highly expressed in rheumatoid synovial cells and may be involved in the pathogenesis of rheumatoid arthritis (RA). It functions as an anti-apoptotic factor that is responsible for the outgrowth of synovial cells during the development of RA. It promotes inositol-requiring enzyme 1 (IRE1) ubiquitination and degradation in synovial fibroblasts with collagen-induced arthritis. Furthermore, the upregulation of synoviolin may represent a protective response against neurodegeneration in Parkinson's disease (PD). In addition, synoviolin is involved in liver fibrogenesis. Synoviolin contains a C3H2C2-type RING-H2 finger.

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                ....*....|....*....|....*....|....*....|
gi 18424150 144 CGICME-MNSKVVLPNCTHSLCIKCYRDWRGRSQSCPFCR 182
Cdd:cd16479   4 CIICREeMTVGAKKLPCGHIFHLSCLRSWLQRQQTCPTCR 43

RING finger, HC subclass, found in RING finger protein 213 (RNF213) and similar proteins; RNF213, also known as ALK lymphoma oligomerization partner on chromosome 17 or Moyamoya steno-occlusive disease-associated AAA+ and RING finger protein (mysterin), is an intracellular soluble protein that functions as an E3 ubiquitin-protein ligase and AAA+ ATPase, which possibly contributes to vascular development through mechanical processes in the cell. It plays a unique role in endothelial cells for proper gene expression in response to inflammatory signals from the environment. Mutations in RNF213 may be associated with Moyamoya disease (MMD), an idiopathic cerebrovascular occlusive disorder prevalent in East Asia. It also acts as a nuclear marker for acanthomorph phylogeny. RNF213 contains two tandem enzymatically active AAA+ ATPase modules and a C3HC4-type RING-HC finger. It can form a huge ring-shaped oligomeric complex.

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                ....*....|....*....|....*....|....*....|....*..
gi 18424150 144 CGICME-MNSKVVLPnCTHSLCIKCYRDWRGRSQSCPFCRDSLKRVD 189
Cdd:cd16561   5 CSICLEdLNDPVKLP-CDHVFCEECIRQWLPGQMSCPLCRTELPDDF 50

RING finger, HC subclass, found in E3 ubiquitin-protein ligase Cbl-b and similar proteins; Cbl-b, also known as Casitas B-lineage lymphoma proto-oncogene b, RING finger protein 56 (RNF56), SH3-binding protein Cbl-b, or signal transduction protein Cbl-b, has been identified as a regulator of antigen-specific, T cell-intrinsic, peripheral immune tolerance, a state also known as clonal anergy. It may inhibit activation of the p85 subunit of phosphoinositide 3-kinase (PI3K), protein kinase C-theta (PKC-theta), and phospholipase C-gamma1 (PLC-gamma1) and negatively regulates T-cell receptor-induced transcription factor nuclear factor kappaB (NF-kappaB) activation. In addition, Cbl-b may target multiple signaling molecules involved in transforming growth factor (TGF)-beta-mediated transactivation pathways. Cbl-b contains a tyrosine-kinase-binding domain (TKB, also known as the phosphotyrosine binding PTB domain, is composed of a four helix-bundle, a Ca2+ binding EF-hand and a highly variant SH2 domain), a proline rich domain, a nuclear localization signal, a C3HC4-type RING-HC finger and an ubiquitin-associated (UBA) domain.

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                ....*....|....*....|....*....|....*....|....
gi 18424150 144 CGICMEMNSKVVLPNCTHSLCIKCYRDWR-GRSQSCPFCRDSLK 186
Cdd:cd16709  23 CKICAENDKDVKIEPCGHLMCTSCLTAWQeSDGQGCPFCRCEIK 66

first RING finger, HC subclass, found in Arabidopsis thaliana ORTHRUS and similar proteins; This subfamily includes Arabidopsis thaliana ORTHRUS 1-5. They are E3 ubiquitin-protein ligases that may participate in CpG methylation-dependent transcriptional regulation and/or epigenetic transcriptional silencing. ORTHRUS 1 mediates ubiquitination with the E2 ubiquitin-conjugating enzymes UBC11, UBC8 and UBC8 homologs (e.g. UBC10, UBC11, UBC28 and UBC29) but not with UBC27, UBC30, UBC32, UBC34 and UBC36. ORTHRUS 2 and 5 mediate ubiquitination with the E2 ubiquitin-conjugating enzyme UBC11. ORTHRUS 1 and 2 promote methylation-mediated gene silencing leading, for example, to early flowering. They can bind to CpG, CpNpG, and CpNpN DNA motifs, with a strong preference for methylated forms, and with highest affinity for CpG substrates. Members of this subfamily contain two typical C3HC4-type RING-HC fingers. This model corresponds to the first one.

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                ....*....|....*....|....*....|....*....|
gi 18424150 144 CGICMEMNSKVVLPNCTHSLCIKCYRDWRGR-SQSCPFCR 182
Cdd:cd23138   5 CSFCMQLPERPVTTPCGHNFCLKCFQKWMGQgKKTCGTCR 44

RING finger, HC subclass, found in muscle-specific RING finger protein 1 (MuRF-1) and similar proteins; MuRF-1, also known as tripartite motif-containing protein 63 (TRIM63), RING finger protein 28 (RNF28), iris RING finger protein, or striated muscle RING zinc finger, is an E3 ubiquitin-protein ligase in ubiquitin-mediated muscle protein turnover. It is predominantly fast (type II) fibre-associated in skeletal muscle and can bind to many myofibrillar proteins, including titin, nebulin, the nebulin-related protein NRAP, troponin-I (TnI), troponin-T (TnT), myosin light chain 2 (MLC-2), myotilin, and T-cap. The early and robust upregulation of MuRF-1 is triggered by disuse, denervation, starvation, sepsis, or steroid administration resulting in skeletal muscle atrophy. It also plays a role in maintaining titin M-line integrity. It associates with the periphery of the M-line lattice and may be involved in the regulation of the titin kinase domain. It also participates in muscle stress response pathways and gene expression. MuRF-1 belongs to the C-II subclass of the TRIM (tripartite motif) family of proteins that are defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, Bbox2, and a coiled coil region, as well as a COS (carboxyl-terminal subgroup one signature) box, and an acidic residue-rich (AR) domain. It also harbors a MURF family-specific conserved box (MFC) between its RING-HC finger and Bbox domains.

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                ....*....|....*....|....*....|....*....|....*....|....*...
gi 18424150 144 CGICMEMNSK--VVLPnCTHSLCIKCYRD--------WRGRSQS---------CPFCR 182
Cdd:cd16759   6 CPICLEMFTKpvVILP-CQHNLCRKCANDifqaanpyWQSRGTSmlgsggrfrCPSCR 62

RING finger, HC subclass, found in RING finger protein 168 (RNF168) and similar proteins; RNF168 is an E3 ubiquitin-protein ligase that promotes noncanonical K27 ubiquitination to signal DNA damage. It, together with RNF8, functions as a DNA damage response (DDR) factor that promotes a series of ubiquitylation events on substrates, such as H2A and H2AX with H2AK13/15 ubiquitylation, facilitates recruitment of repair factors p53-binding protein 1 (53BP1) or the RAP80-BRCA1 complex to sites of double-strand breaks (DSBs), and inhibits homologous recombination (HR) in cells deficient in the tumor suppressor BRCA1. RNF168 also promotes H2A neddylation, which antagonizes ubiquitylation of H2A and regulates DNA damage repair. Moreover, RNF168 forms a functional complex with RAD6A or RAD6B during the DNA damage response. RNF168 contains an N-terminal C3HC4-type RING-HC finger that catalyzes H2A-K15ub and interacts with H2A, and two MIU (motif interacting with ubiquitin) domains responsible for the interaction with K63 linked poly-ubiquitin.

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                ....*....|....*....|....*....|....*....|....*...
gi 18424150 144 CGICMEMNSKVVLPNCTHSLCIKCYR-DWRGRSQSCPFCRdslKRVDS 190
Cdd:cd16550   3 CPICLEILVEPVTLPCNHTLCMPCFQsTVEKASLCCPLCR---LRISS 47

RING finger, HC subclass, found in tripartite motif-containing protein TRIM25 and similar proteins; TRIM25, also known as estrogen-responsive finger protein (EFP), RING finger protein 147 (RNF147), or RING-type E3 ubiquitin transferase, is an E3 ubiquitin/ISG15 ligase that is induced by estrogen and is therefore particularly abundant in placenta and uterus. TRIM25 regulates various cellular processes through E3 ubiquitin ligase activity, transferring ubiquitin and ISG15 to target proteins. It mediates K63-linked polyubiquitination of retinoic acid inducible gene I (RIG-I) that is crucial for downstream antiviral interferon signaling. It is also required for melanoma differentiation-associated gene 5 (MDA5) and mitochondrial antiviral signaling (MAVS, also known as IPS-1, VISA, Cardiff) mediated activation of nuclear factor-kappaB (NF-kappaB) and interferon production. Upon UV irradiation, TRIM25 interacts with mono-ubiquitinated PCNA and promotes its ISG15 modification (ISGylation), suggesting a crucial role in termination of error-prone translesion DNA synthesis. TRIM25 also functions as a novel regulator of p53 and Mdm2. It enhances p53 and Mdm2 abundance by inhibiting their ubiquitination and degradation in 26S proteasomes. Meanwhile, it inhibits p53's transcriptional activity and dampens the response to DNA damage, and is essential for medaka development and this dependence is rescued by silencing of p53. Moreover, TRIM25 is involved in the host cellular innate immune response against retroviral infection. It interferes with the late stage of feline leukemia virus (FeLV) replication. Furthermore, TRIM25 acts as an oncogene in gastric cancer. Its blockade by RNA interference inhibits migration and invasion of gastric cancer cells through transforming growth factor-beta (TGF-beta) signaling, suggesting it presents a novel target for the detection and treatment of gastric cancer. In addition, TRIM25 acts as an RNA-specific activator for Lin28a/TuT4-mediated uridylation. TRIM25 belongs to the C-IV subclass of TRIM (tripartite motif) family of proteins that are defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, Bbox1 and Bbox2, and a coiled coil region, as well as a B30.2/SPRY (SplA and ryanodine receptor) domain positioned C-terminal to the RBCC domain.

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                ....*....|....*....|....*....|....*....|....*....
gi 18424150 144 CGICMEM-NSKVVLPnCTHSLCIKC----YRDWRGRSQSCPFCRDSLKR 187
Cdd:cd16597   8 CSICLELfKDPVTLP-CGHNFCGVCiektWDSQHGSEYSCPQCRATFPR 55

RING finger, HC subclass, found in RING finger protein 5 (RNF5) and similar proteins; RNF5, also known as protein G16 or Ram1, is an E3 ubiquitin-protein ligase anchored to the outer membrane of the endoplasmic reticulum (ER). It acts at early stages of cystic fibrosis (CF) transmembrane conductance regulator (CFTR) biosynthesis and functions as a target for therapeutic modalities to antagonize mutant CFTR proteins in CF patients carrying the F508del allele. It also regulates the turnover of specific G protein-coupled receptors by ubiquitinating JNK-associated membrane protein (JAMP) and preventing proteasome recruitment. RNF5 limits basal levels of autophagy and influences susceptibility to bacterial infection through the regulation of ATG4B stability. It is also involved in the degradation of Pendrin, a transmembrane chloride/anion exchanger highly expressed in thyroid, kidney, and inner ear. RNF5 plays an important role in cell adhesion and migration. It can modulate cell migration by ubiquitinating paxillin. Furthermore, RNF5 interacts with virus-induced signaling adaptor (VISA) at mitochondria in a viral infection-dependent manner, and further targets VISA at K362 and K461 for K48-linked ubiquitination and degradation after viral infection. It also negatively regulates virus-triggered signaling by targeting MITA, also known as STING, for ubiquitination and degradation at the mitochondria. In addition, RNF5 determines breast cancer response to ER stress-inducing chemotherapies through the regulation of the L-glutamine carrier proteins SLC1A5 and SLC38A2 (SLC1A5/38A2). It also has been implicated in muscle organization and in recognition and processing of misfolded proteins. RNF5 contains a C3HC4-type RING-HC finger.

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                ....*....|....*....|....*....|....*....|....*..
gi 18424150 144 CGICMEMNSKVVLPNCTHSLCIKCYRDW---RGRSQSCPFCRDSLKR 187
Cdd:cd16743   3 CNICLETARDAVVSLCGHLFCWPCLHQWletRPERQECPVCKAGISR 49

RING finger, HC subclass, found in bifunctional apoptosis regulator (BAR); BAR, also known as RING finger protein 47, was originally identified as an inhibitor of Bax-induced apoptosis. It participates in the block of apoptosis induced by TNF-family death receptors (extrinsic pathway) and mitochondria-dependent apoptosis (intrinsic pathway). BAR is predominantly expressed by neurons in the central nervous system and is involved in the regulation of neuronal survival. It is an endoplasmic reticulum (ER)-associated RING-type E3 ubiquitin ligase that interacts with BI-1 protein and post-translationally regulates its stability, as well as functioning in ER stress. BAR contains an N-terminal C3HC4-type RING-HC finger, a SAM domain, a coiled-coil domain, and a C-terminal transmembrane (TM) domain. This model corresponds to the RING-HC finger responsible for the binding of ubiquitin conjugating enzymes (E2s).

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                ....*....|....*....|....*....|....*....|...
gi 18424150 144 CGICMEMNSKVVLPNCTHSLCIKCYRDW--RGRSQSCPFCRDS 184
Cdd:cd16497   4 CHCCYDLLVNPTTLNCGHSFCRHCLALWwkSSKKTECPECRQK 46

RING finger, H2 subclass, found in RING finger protein 181 (RNF181) and similar proteins; RNF181, also known as HSPC238, is a platelet E3 ubiquitin-protein ligase containing a C3H2C3-type RING-H2 finger. It interacts with the KVGFFKR motif of platelet integrin alpha(IIb)beta3, suggesting a role for RNF181-mediated ubiquitination in integrin and platelet signaling. It also suppresses the tumorigenesis of hepatocellular carcinoma (HCC) through the inhibition of extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK) signaling in the liver.

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                ....*....|....*....|....*....|....*....|....*
gi 18424150 144 CGICM---EMNSKVVLPNCTHSLCIKCYRDWRGRSQSCPFCRDSL 185
Cdd:cd16669   2 CPICLlefEEGETVKQLPCKHSFHSDCILPWLGKTNSCPLCRHEL 46

RING finger, HC subclass, found in Ret finger protein-like 4B (RFPL4B) and similar proteins; RFPL4B, also called RING finger protein 211 (RNF211), is an uncharacterized RING finger protein containing a typical C3HC4-type RING-HC finger.

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                ....*....|....*....|....*....|....*....|....*...
gi 18424150 144 CGICMEMNSKVVLPNCTHSLCIKCYRDWRGRSQ----SCPFCRDSLKR 187
Cdd:cd16623  11 CPICLDFFSHPISLSCAHIFCFDCIQKWMTKREdsilTCPLCRKEQKK 58

RING finger, HC subclass, found in RING finger protein 4 (RNF4) and similar proteins; RNF4, also known as small nuclear ring finger protein (SNURF), is a SUMO-targeted E3 ubiquitin-protein ligase with a pivotal function in the DNA damage response (DDR) by interacting with the deubiquitinating enzyme ubiquitin-specific protease 11 (USP11), a known DDR-component, and further facilitating DNA repair. It plays a novel role in preventing the loss of intact chromosomes and ensures the maintenance of chromosome integrity. Moreover, RNF4 is responsible for the UbcH5A-catalyzed formation of K48 chains that target SUMO-modified promyelocytic leukemia (PML) protein for proteasomal degradation in response to arsenic treatment. It also interacts with telomeric repeat binding factor 2 (TRF2) in a small ubiquitin-like modifier (SUMO)-dependent manner and preferentially targets SUMO-conjugated TRF2 for ubiquitination through SUMO-interacting motifs (SIMs). Furthermore, RNF4 can form a complex with a Ubc13-ubiquitin conjugate and Ube2V2. It catalyzes K63-linked polyubiquitination by the Ube2V2-Ubc13 (ubiquitin-loaded) complex. Meanwhile, RNF4 negatively regulates nuclear factor kappa B (NF-kappaB) signaling by down-regulating transforming growth factor beta (TGF-beta)-activated kinase 1 (TAK1)-TAK1-binding protein2 (TAB2). RNF4 contains four SIMs followed by a C3HC4-type RING-HC finger at the C-terminus.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*....
gi 18424150 144 CGICMEMNSK-------VVLPNCTHSLCIKCYRDWRGRSQSCPFCRDSL 185
Cdd:cd16533   6 CPICMDGYSEivqsgrlIVSTECGHVFCSQCLRDSLKNANTCPTCRKKL 54

Zinc finger, C3HC4 type (RING finger); The C3HC4 type zinc-finger (RING finger) is a cysteine-rich domain of 40 to 60 residues that coordinates two zinc ions, and has the consensus sequence: C-X2-C-X(9-39)-C-X(1-3)-H-X(2-3)-C-X2-C-X(4-48)-C-X2-C where X is any amino acid. Many proteins containing a RING finger play a key role in the ubiquitination pathway.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|.
gi 18424150   144 CGICME--MNSKVVLPnCTHSLCIKCYRDW-RGRSQSCPFC 181
Cdd:pfam00097   1 CPICLEepKDPVTLLP-CGHLFCSKCIRSWlESGNVTCPLC 40

RING-finger-containing E3 ubiquitin ligase [Signal transduction mechanisms];

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*
gi 18424150 144 CGICMEMNSKVVLPNCTHSLCIKCYRDWRGRSQSCPFCR----DSLKRVDSGDLW 194
Cdd:COG5432  28 CRICDCRISIPCETTCGHTFCSLCIRRHLGTQPFCPVCRedpcESRLRGSSGSRE 82

second RING finger, HC subclass, found in the LON peptidase N-terminal domain and RING finger protein family; The LON peptidase N-terminal domain and RING finger protein family includes LONRF1 (also known as RING finger protein 191 or RNF191), LONRF2 (also known as RING finger protein 192, RNF192, or neuroblastoma apoptosis-related protease), LONRF3 (also known as RING finger protein 127 or RNF127), which are characterized by containing two C3HC4-type RING-HC fingers, four tetratricopeptide (TPR) repeats, and an ATP-dependent protease La (LON) substrate-binding domain at the C-terminus. Their biological functions remain unclear. This model corresponds to the second RING-HC finger.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|..
gi 18424150 144 CGICMEMNSKVVLPNCTHSLCIKCYRDWRGRSQSCPFCRDSL 185
Cdd:cd16514   4 CSLCLRLLYEPVTTPCGHTFCRACLERCLDHSPKCPLCRTSL 45

RING finger, H2 subclass, found in E3 ubiquitin-protein ligase RNF6, RNF12, and similar proteins; RNF6 is an androgen receptor (AR)-associated protein that induces AR ubiquitination and promotes AR transcriptional activity. RNF6-induced ubiquitination may regulate AR transcriptional activity and specificity by modulating cofactor recruitment. RNF6 is overexpressed in hormone-refractory human prostate cancer tissues and required for prostate cancer cell growth under androgen-depleted conditions. RNF6 also regulates local serine/threonine kinase LIM kinase 1 (LIMK1) levels in axonal growth cones. RNF6-induced LIMK1 polyubiquitination is mediated via K48 of ubiquitin and leads to proteasomal degradation of the kinase. RNF6 binds and upregulates the Inha promoter, and functions as a transcription regulatory protein in the mouse sertoli cell. It acts as a potential tumor suppressor gene involved in the pathogenesis of esophageal squamous cell carcinoma (ESCC). RNF12, also known as LIM domain-interacting RING finger protein, or RING finger LIM domain-binding protein (R-LIM), is an E3 ubiquitin-protein ligase encoded by gene RLIM that is crucial for normal embryonic development in some species and for normal X inactivation in mice. It thus functions as a major sex-specific epigenetic regulator of female mouse nurturing tissues. RNF12 is widely expressed during embryogenesis, and mainly localizes to the cell nucleus, where it regulates the levels of many proteins, including CLIM, LMO, HDAC2, TRF1, SMAD7, and REX1, by proteasomal degradation. Both RNF6 and RNF12 contain a well conserved C3H2C3-type RING-H2 finger.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|..
gi 18424150 144 CGICM---EMNSKVVLPNCTHSLCIKCYRDWRGRSQSCPFCR 182
Cdd:cd16467   2 CTICLgeyETGEKLRRLPCSHEFHSECVDRWLKENSSCPICR 43

RING finger, HC subclass, found in muscle-specific RING finger proteins TRIM63/MuRF-1, TRIM55/MuRF-2 and TRIM54/MuRF-3; This subfamily corresponds to a group of striated muscle-specific tripartite motif (TRIM) proteins, including TRIM63/MuRF-1, TRIM55/MuRF-2, and TRIM54/MuRF-3, which function as E3 ubiquitin ligases in ubiquitin-mediated muscle protein turnover. They are tightly developmentally regulated in skeletal muscle and associate with different cytoskeleton components, such as microtubules, Z-disks and M-bands, as well as with metabolic enzymes and nuclear proteins. They also cooperate with diverse proteins implicated in selective protein degradation by the proteasome and autophagosome, and target proteins of metabolic regulation, sarcomere assembly and transcriptional regulation. Moreover, MURFs display variable fibre-type preferences. TRIM63/MuRF-1 is predominantly fast (type II) fibre-associated in skeletal muscle. TRIM55/MuRF-2 is predominantly slow-fibre associated. TRIM54/MuRF-3 is ubiquitously present. They play an active role in microtubule-mediated sarcomere assembly. MuRFs belong to the C-II subclass of the TRIM family of proteins that are defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, Bbox2, and a coiled coil region, as well as a COS (carboxyl-terminal subgroup one signature) box, and an acidic residue-rich (AR) domain positioned C-terminal to the RBCC domain. They also harbor a MURF family-specific conserved box (MFC) between its RING-HC finger and Bbox domains.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*
gi 18424150 144 CGICMEMNSK--VVLPnCTHSLCIKCYRD--------WRGRSQS------CPFCR 182
Cdd:cd16577   3 CPICLEMFTKpvVILP-CQHNLCRKCANDifqarnpyWPTTTMGsggrfrCPSCR 56

RING finger, HC subclass, found in RING finger protein 185 (RNF185) and similar proteins; RNF185 is an E3 ubiquitin-protein ligase of endoplasmic reticulum-associated degradation (ERAD) that targets cystic fibrosis transmembrane conductance regulator (CFTR). It controls the degradation of CFTR and CFTR F508del allele in a RING- and proteasome-dependent manner, but does not control that of other classical ERAD model substrates. It also negatively regulates osteogenic differentiation by targeting dishevelled2 (Dvl2), a key mediator of the Wnt signaling pathway, for degradation. Moreover, RNF185 regulates selective mitochondrial autophagy through interaction with the Bcl-2 family protein BNIP1. It also plays an important role in cell adhesion and migration through the modulation of cell migration by ubiquitinating paxillin. RNF185 contains a C3HC4-type RING-HC finger.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*..
gi 18424150 144 CGICMEMNSKVVLPNCTHSLCIKCYRDW---RGRSQSCPFCRDSLKR 187
Cdd:cd16744   3 CNICLDTAKDAVVSLCGHLFCWPCLHQWletRPNRQVCPVCKAGISR 49

RING finger, HC subclass, found in tripartite motif-containing protein 69 (TRIM69) and similar proteins; TRIM69, also known as RFP-like domain-containing protein trimless or RING finger protein 36 (RNF36), is a testis E3 ubiquitin-protein ligase that plays a specific role in apoptosis and may also play an important role in germ cell homeostasis during spermatogenesis. TRIM69 belongs to the C-IV subclass of the TRIM (tripartite motif) family of proteins that are defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, Bbox1 and Bbox2, and a coiled coil region, as well as a B30.2/SPRY (SplA and ryanodine receptor) domain positioned C-terminal to the RBCC domain.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|..
gi 18424150 144 CGICMEMNSKVVLPNCTHSLCIKCYRDWRGRSQ---SCPFCR 182
Cdd:cd16611   7 CPLCLDFFRDPVMLSCGHNFCQSCITGFWELQAedtTCPECR 48

RING finger, HC subclass, found in RING finger protein 138 (RNF138) and similar proteins; RNF138, also known as Nemo-like kinase-associated RING finger protein (NARF) or NLK-associated RING finger protein, is an E3 ubiquitin-protein ligase that plays an important role in glioma cell proliferation, apoptosis, and cell cycle. It specifically cooperates with the E2 conjugating enzyme E2-25K (Hip-2/UbcH1), regulates the ubiquitylation and degradation of T cell factor/lymphoid enhancer factor (TCF/LEF), and further suppresses Wnt-beta-catenin signaling. RNF138, together with three closely related proteins: RNF114, RNF125 and RNF166, forms a novel family of ubiquitin ligases with a C3HC4-type RING-HC finger, a C2HC-, and two C2H2-type zinc fingers, as well as a ubiquitin interacting motif (UIM).

                        10        20        30        40
                ....*....|....*....|....*....|....*....|..
gi 18424150 144 CGICME-MNSKVVLPNCTHSLCIKCYRD-WRGRSQSCPFCRD 183
Cdd:cd16544   5 CPVCQEvLKDPVELPPCRHIFCKACILLaLRSSGARCPLCRG 46

RING-type zinc-finger; This zinc-finger is a typical RING-type of plant ubiquitin ligases.

                          10        20        30
                  ....*....|....*....|....*....|....*....
gi 18424150   144 CGICMEMNSKVVLPnCTHSLCIKC---YRDWRGRSQSCP 179
Cdd:pfam13445   1 CPICLELFTDPVLP-CGHTFCRECleeMSQKKGGKFKCP 38

RING finger, HC subclass, found in muscle-specific RING finger protein 2 (MuRF-2) and similar proteins; MuRF-2, also known as tripartite motif-containing protein 55 (TRIM55) or RING finger protein 29 (RNF29), is a muscle-specific E3 ubiquitin-protein ligase in ubiquitin-mediated muscle protein turnover and is also a ligand of the transactivation domain of the serum response transcription factor (SRF). It is predominantly slow-fibre associated and highly expressed in embryonic skeletal muscle. MuRF-2 associates transiently with microtubules, myosin, and titin during sarcomere assembly. It has been implicated in microtubule, intermediate filament, and sarcomeric M-line maintenance in striated muscle development, as well as in signaling from the sarcomere to the nucleus. It plays an important role in the earliest stages of skeletal muscle differentiation and myofibrillogenesis. It is developmentally downregulated and is assembled at the M-line region of the sarcomere and with microtubules. MuRF-2 belongs to the C-II subclass of the TRIM (tripartite motif) family of proteins that are defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, Bbox2, and a coiled coil region, as well as a COS (carboxyl-terminal subgroup one signature) box, and an acidic residue-rich (AR) domain. It also harbors a MURF family-specific conserved box (MFC) between its RING-HC finger and Bbox domains.

                        10        20
                ....*....|....*....|....*....
gi 18424150 144 CGICMEMNSK--VVLPnCTHSLCIKCYRD 170
Cdd:cd16760   6 CPICLEMFTKpvVILP-CQHNLCRKCAND 33

Modified RING finger, HC subclass (C3HC3D-type), found in Caenorhabditis elegans putative GTP-binding protein trim-23 homolog (arc-1) and similar proteins; arc-1, also called RING-type E3 ubiquitin transferase arc-1, is an E3 ubiquitin-protein ligase that mediates E2-dependent protein ubiquitination. arc-1 contains a modified C3HC3D-type RING-HC finger.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*....
gi 18424150 144 CGICMEMNSKV-------VLPNCTHSLCIKCYRDWRGRSQS---CPFCR 182
Cdd:cd23124   4 CGICQQEYSADdplliprILTECGHTICTNCAGTILGQSSGsifCPFDR 52

RING finger, HC subclass, found in RING finger protein 125 (RNF125); RNF125, also known as T-cell RING activation protein 1 (TRAC-1), is an E3 ubiquitin-protein ligase that is predominantly expressed in lymphoid cells, and functions as a positive regulator of T cell activation. It also down-modulates HIV replication and inhibits pathogen-induced cytokine production. It negatively regulates type I interferon signaling, which conjugates Lys(48)-linked ubiquitination to retinoic acid-inducible gene-I (RIG-I) and subsequently leads to the proteasome-dependent degradation of RIG-I. Further, RNF125 conjugates ubiquitin to melanoma differentiation-associated gene 5 (MDA5), a family protein of RIG-I. It thus acts as a negative regulator of RIG-I signaling, and is a direct target of miR-15b in the context of Japanese encephalitis virus (JEV) infection. Moreover, RNF125 binds to and ubiquitinates JAK1, prompting its degradation and inhibition of receptor tyrosine kinase (RTK) expression. It also negatively regulates p53 function through physical interaction and ubiquitin-mediated proteasome degradation. Mutations in RNF125 may lead to overgrowth syndromes (OGS). RNF125, together with three closely related proteins: RNF114, RNF138 and RNF166, forms a novel family of ubiquitin ligases with a C3HC4-type RING-HC finger, a C2HC-, and two C2H2-type zinc fingers, as well as a ubiquitin interacting motif (UIM). The UIM of RNF125 binds K48-linked poly-ubiquitin chains and is, together with the RING domain, required for auto-ubiquitination.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*
gi 18424150 144 CGICMEMNSKVVLPNCTHSLCIKCYR-DWRGRSQSCPFCRDSLKR 187
Cdd:cd16542   4 CAVCLEVLHQPVRTRCGHVFCRPCIAtSLRNNTWTCPYCRAYLSS 48

RING finger, HC subclass, found in RING finger protein 112 (RNF112) and similar proteins; RNF112, also known as brain finger protein (BFP), zinc finger protein 179 (ZNF179), or neurolastin, is a peripheral membrane protein that is predominantly expressed in the central nervous system and localizes to endosomes. It contains functional GTPase and C3HC4-type RING-HC finger domains and has been identified as a brain-specific dynamin family GTPase that affects endosome size and spine density. Moreover, RNF112 acts as a downstream target of sigma-1 receptor (Sig-1R) regulation and may play a novel role in neuroprotection by mediating the neuroprotective effects of dehydroepiandrosterone (DHEA) and its sulfated analog (DHEAS).

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*..
gi 18424150 144 CGICMEMNSKVVLPNCTHSLCIKCYRDWR---GRSQSCPFCRDSLKR 187
Cdd:cd16538   5 CSICLERLREPISLDCGHDFCIRCFSTHRipgCEPPCCPECRKICKQ 51