Immunoglobulin (Ig) light chain, kappa type, variable (V) domain; The members here are composed of the immunoglobulin (Ig) light chain, kappa type, variable (V) domain. This group contains the standard Ig superfamily V-set AGFCC'C"/DEB domain topology. The basic structure of Ig molecules is a tetramer of two light chains and two heavy chains linked by disulfide bonds. There are two types of light chains: kappa and lambda, each composed of a constant domain (CL) and a variable domain (VL). There are five types of heavy chains (alpha, gamma, delta, epsilon, and mu), which determines the type of immunoglobulin formed: IgA, IgG, IgD, IgE, and IgM, respectively. In higher vertebrates, there are two types of light chain, designated kappa and lambda, which seem to be functionally identical, and can associate with any of the heavy chains.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1973619857   2 IVLTQSPGTLSLSPGERATLSCRASQSVSS-YLAWYQQKPGQAPRLLIFDASIRATGIPARFSGSGSGTDFTLTISSLEP 80
Cdd:cd04980     1 IVMTQSPASLSVSPGERVTISCKASQSISSnYLAWYQQKPGQAPKLLIYYASTLHSGVPSRFSGSGSGTDFTLTISSVEP 80

                          90       100
                  ....*....|....*....|....*.
gi 1973619857  81 EDFAVYYCQQRSNWPLTFGQGTKLEI 106
Cdd:cd04980    81 EDAAVYYCQQGYTFPYTFGGGTKLEI 106

Immunoglobulin (Ig) light chain, kappa type, variable (V) domain; The members here are composed of the immunoglobulin (Ig) light chain, kappa type, variable (V) domain. This group contains the standard Ig superfamily V-set AGFCC'C"/DEB domain topology. The basic structure of Ig molecules is a tetramer of two light chains and two heavy chains linked by disulfide bonds. There are two types of light chains: kappa and lambda, each composed of a constant domain (CL) and a variable domain (VL). There are five types of heavy chains (alpha, gamma, delta, epsilon, and mu), which determines the type of immunoglobulin formed: IgA, IgG, IgD, IgE, and IgM, respectively. In higher vertebrates, there are two types of light chain, designated kappa and lambda, which seem to be functionally identical, and can associate with any of the heavy chains.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1973619857   2 IVLTQSPGTLSLSPGERATLSCRASQSVSS-YLAWYQQKPGQAPRLLIFDASIRATGIPARFSGSGSGTDFTLTISSLEP 80
Cdd:cd04980     1 IVMTQSPASLSVSPGERVTISCKASQSISSnYLAWYQQKPGQAPKLLIYYASTLHSGVPSRFSGSGSGTDFTLTISSVEP 80

                          90       100
                  ....*....|....*....|....*.
gi 1973619857  81 EDFAVYYCQQRSNWPLTFGQGTKLEI 106
Cdd:cd04980    81 EDAAVYYCQQGYTFPYTFGGGTKLEI 106

Immunoglobulin V-set domain; This domain is found in antibodies as well as neural protein P0 and CTL4 amongst others.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1973619857   6 QSPGTLSLSPGERATLSCRASQSVSS---YLAWYQQKPGQAPRLLI--FDASIRATGIPARFSGSG--SGTDFTLTISSL 78
Cdd:pfam07686   1 QTPREVTVALGGSVTLPCTYSSSMSEastSVYWYRQPPGKGPTFLIayYSNGSEEGVKKGRFSGRGdpSNGDGSLTIQNL 80

                          90       100
                  ....*....|....*....|....*...
gi 1973619857  79 EPEDFAVYYCQQRSNWPLTFGQGTKLEI 106
Cdd:pfam07686  81 TLSDSGTYTCAVIPSGEGVFGKGTRLTV 108

Immunoglobulin (Ig) light chain, kappa type, variable (V) domain; The members here are composed of the immunoglobulin (Ig) light chain, kappa type, variable (V) domain. This group contains the standard Ig superfamily V-set AGFCC'C"/DEB domain topology. The basic structure of Ig molecules is a tetramer of two light chains and two heavy chains linked by disulfide bonds. There are two types of light chains: kappa and lambda, each composed of a constant domain (CL) and a variable domain (VL). There are five types of heavy chains (alpha, gamma, delta, epsilon, and mu), which determines the type of immunoglobulin formed: IgA, IgG, IgD, IgE, and IgM, respectively. In higher vertebrates, there are two types of light chain, designated kappa and lambda, which seem to be functionally identical, and can associate with any of the heavy chains.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1973619857   2 IVLTQSPGTLSLSPGERATLSCRASQSVSS-YLAWYQQKPGQAPRLLIFDASIRATGIPARFSGSGSGTDFTLTISSLEP 80
Cdd:cd04980     1 IVMTQSPASLSVSPGERVTISCKASQSISSnYLAWYQQKPGQAPKLLIYYASTLHSGVPSRFSGSGSGTDFTLTISSVEP 80

                          90       100
                  ....*....|....*....|....*.
gi 1973619857  81 EDFAVYYCQQRSNWPLTFGQGTKLEI 106
Cdd:cd04980    81 EDAAVYYCQQGYTFPYTFGGGTKLEI 106

Immunoglobulin (Ig) lambda light chain variable (V) domain; The members here are composed of the immunoglobulin (Ig) light chain, lambda type, variable (V) domain. The basic structure of Ig molecules is a tetramer of two light chains and two heavy chains linked by disulfide bonds. There are two types of light chains: kappa and lambda, each composed of a constant domain (CL) and a variable domain (VL). There are five types of heavy chains (alpha, gamma, delta, epsilon, and mu), which determines the type of immunoglobulin formed: IgA, IgG, IgD, IgE, and IgM, respectively. In higher vertebrates, there are two types of light chain, designated kappa and lambda, which seem to be functionally identical, and can associate with any of the heavy chains. Members of this group contain standard Ig superfamily V-set AGFCC'C"/DEB domain topology.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1973619857   3 VLTQsPGTLSLSPGERATLSCRASQSVSS--YLAWYQQKPGQAPRLLIFDASIRATGIPARFSGSGSGTDFTLTISSLEP 80
Cdd:cd04984     1 VLTQ-PSSLSVSPGETVTITCTGSSGNISgnYVNWYQQKPGSAPRYLIYEDKHRPSGIPDRFSGSKSGNTASLTISGAQT 79

                          90       100
                  ....*....|....*....|....
gi 1973619857  81 EDFAVYYCQQRSNWPLTFGQGTKL 104
Cdd:cd04984    80 EDEADYYCQVWDSNSYVFGGGTKL 103

Immunoglobulin (Ig) variable (V) domain of T-cell receptor (TCR) beta chain; The members here are composed of the immunoglobulin (Ig) variable domain of the beta chain of alpha/beta T-cell antigen receptors (TCRs). TCRs mediate antigen recognition by T lymphocytes, and are composed of alpha and beta, or gamma and delta, polypeptide chains with variable (V) and constant (C) regions. This group includes the variable domain of the alpha chain of alpha/beta TCRs. Alpha/beta TCRs recognize antigen as peptide fragments presented by major histocompatibility complex (MHC) molecules. The variable domain of TCRs is responsible for antigen recognition, and is located at the N-terminus of the receptor. Gamma/delta TCRs recognize intact protein antigens directly without antigen processing and recognize MHC independently of the bound peptide. Members of this group contain standard Ig superfamily V-set AGFCC'C"/DEB domain topology.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1973619857   4 LTQSPGTLSLSPGERATLSCRASQSVSsYLAWYQQKPGQAPRLLIFDAS---IRATGIPA-RFSGSG-SGTDFTLTISSL 78
Cdd:cd05899     1 VTQSPRYLIKRRGQSVTLRCSQKSGHD-NMYWYRQDPGKGLQLLFYSYGgglNEEGDLPGdRFSASRpSLTRSSLTIKSA 79

                          90       100
                  ....*....|....*....|....*....
gi 1973619857  79 EPEDFAVYYC---QQRSNWPLTFGQGTKL 104
Cdd:cd05899    80 EPEDSAVYLCassLGGGADEAYFGPGTRL 108

Immunoglobulin V-Type;

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1973619857   19 ATLSCRASQSVSS--YLAWYQQKPGQAPRLLIF----DASIRATGIPARFSGSG--SGTDFTLTISSLEPEDFAVYYCQQ 90
Cdd:smart00406   2 VTLSCKFSGSTFSsyYVSWVRQPPGKGLEWLGYigsnGSSYYQESYKGRFTISKdtSKNDVSLTISNLRVEDTGTYYCAV 81

Immunoglobulin (Ig) variable (V) domain of T-cell receptor (TCR) gamma chain; The members here are composed of the immunoglobulin (Ig) variable (V) domain of the gamma chain of gamma/delta T-cell receptors (TCRs). TCRs mediate antigen recognition by T lymphocytes, and are heterodimers consisting of alpha and beta chains or gamma and delta chains. Each chain contains a variable (V) and a constant (C) region. The majority of T cells contain alpha/beta TCRs, but a small subset contain gamma/delta TCRs. Alpha/beta TCRs recognize antigens as peptide fragments presented by major histocompatibility complex (MHC) molecules. Gamma/delta TCRs recognize intact protein antigens directly without antigen processing and recognize MHC independently of the bound peptide. Gamma/delta T cells can also be stimulated by non-peptide antigens such as small phosphate- or amine-containing compounds. The variable domain of gamma/delta TCRs is responsible for antigen recognition and is located at the N-terminus of the receptor. Members of this group contain the standard Ig superfamily V-set AGFCC'C"/DEB domain topology.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1973619857   4 LTQSPGTLSLSPGERATLSCRASQSV--SSYLAWYQQKPGQAP-RLLIFDAS---IRATGIPA-RFSGS--GSGTDFTLT 74
Cdd:cd04982     1 LEQPQLSITREESKSVTISCKVSGIDfsTTYIHWYRQKPGQALeRLLYVSSTsavRKDSGKTKnKFEARkdVGKSTSTLT 80

                          90       100       110
                  ....*....|....*....|....*....|....
gi 1973619857  75 ISSLEPEDFAVYYC----QQRSNWPLTFGQGTKL 104
Cdd:cd04982    81 ITNLEKEDSATYYCayweSGSGYYIKVFGSGTKL 114

Immunoglobulin (Ig) heavy chain (H), variable (V) domain; The members here are composed of the immunoglobulin (Ig) heavy chain (H), variable (V) domain. This group contains the standard Ig superfamily V-set AGFCC'C"/DEB domain topology. The basic structure of Ig molecules is a tetramer of two light chains and two heavy chains linked by disulfide bonds. In Ig, each chain is composed of one variable domain (IgV) and one or more constant domains (IgC); these names reflect the fact that the variability in sequences is higher in the variable domain than in the constant domain. There are five types of heavy chains (alpha, gamma, delta, epsilon, and mu), which determines the type of immunoglobulin formed: IgA, IgG, IgD, IgE, and IgM, respectively. In higher vertebrates, there are two types of light chain, designated kappa and lambda, which can associate with any of the heavy chains. This family includes alpha, gamma, delta, epsilon, and mu heavy chains.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1973619857   6 QSPGTLSLSPGERATLSCRASQ-SVSSY-LAWYQQKPGQAPRLL-----IFDASIRATGIPARFSGS--GSGTDFTLTIS 76
Cdd:cd04981     3 QESGPGLVKPGQSLKLSCKASGfTFTSYgMGWVRQAPGKGLEWIgliypGGGDTYYADSFKGRFTITrdTSKSTAYLQLN 82

                          90       100       110
                  ....*....|....*....|....*....|...
gi 1973619857  77 SLEPEDFAVYYCQQRSNWPLTF-----GQGTKL 104
Cdd:cd04981    83 SLTSEDTAVYYCARGLGGYGYSyfdywGQGTTV 115

Immunoglobulin (Ig)-like variable (V) domain of Cluster of Differentiation (CD) 8 alpha chain; The members here are composed of the immunoglobulin (Ig)-like variable domain of the Cluster of Differentiation (CD) 8 alpha. The CD8 glycoprotein plays an essential role in the control of T-cell selection, maturation, and the T-cell receptor (TCR)-mediated response to peptide antigen. CD8 is comprised of alpha and beta subunits and is expressed as either an alpha/alpha or alpha/beta dimer. Both dimeric isoforms can serve as a coreceptor for T cell activation and differentiation, however they have distinct physiological roles, different cellular distributions, unique binding partners, etc. Each CD8 subunit is comprised of an extracellular domain containing a V-type Ig-like domain, a single pass transmembrane portion, and a short intracellular domain. The Ig domain of CD8 alpha binds to antibodies. Members of this group contain standard Ig superfamily V-set AGFCC'C"/DEB domain topology.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1973619857  16 GERATLSCRASQSVSSYLAWYQQKPGQA--PRLLIFDASIRATGIP-----ARFSGSGSGTDFTLTISSLEPEDFAVYYC 88
Cdd:cd05720    13 GQKVELVCEVLNSVPQGCSWLFQPRGSApqPTFLLYLSSSNKTKWAegldsKRFSGSRSGSSYVLTLKDFRKEDEGYYFC 92

                          90
                  ....*....|...
gi 1973619857  89 QQRSNWPLTFGQG 101
Cdd:cd05720    93 SVISNSVLYFSSF 105

Immunoglobulin domain; This family contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1973619857   3 VLTQSPGTLSLSPGERATLSCRASQSVSSYLAWYqqKPGQAprllifdasIRATGIPARFSGSGSGtdfTLTISSLEPED 82
Cdd:pfam13927   3 VITVSPSSVTVREGETVTLTCEATGSPPPTITWY--KNGEP---------ISSGSTRSRSLSGSNS---TLTISNVTRSD 68

                  ....*..
gi 1973619857  83 FAVYYCQ 89
Cdd:pfam13927  69 AGTYTCV 75

Gammadelta T-cell antigen receptor, variable (V) domain; The members here are composed of the immunoglobulin (Ig) variable (V) domain of the gamma/delta T-cell receptors (TCRs). TCRs mediate antigen recognition by T lymphocytes, and are heterodimers consisting of alpha and beta chains or gamma and delta chains. Each chain contains a variable (V) and a constant (C) region. The majority of T cells contain alpha/beta TCRs, but a small subset contain gamma/delta TCRs. Alpha/beta TCRs recognize antigen as peptide fragments presented by major histocompatibility complex (MHC) molecules. Gamma/delta TCRs recognize intact protein antigens; they recognize protein antigens directly and without antigen processing, and MHC independently of the bound peptide. Gamma/delta T cells can also be stimulated by non-peptide antigens such as small phosphate- or amine-containing compounds. The variable domain of gamma/delta TCRs is responsible for antigen recognition and is located at the N-terminus of the receptor. Members of this group contain standard Ig superfamily V-set AGFCC'C"/DEB domain topology.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1973619857  10 TLSLSPGERATLSCR-ASQSVSSY-LAWYQQKPGQAPRLLIFDASIRATGIPARFSGSGSGTDFTLTISSLEP--EDFAV 85
Cdd:cd20988     7 TVTVSVGKPVTLKCSmKGEAISNYyINWYRKTQGNTMTFIYREGGIYGPGFKDNFRGDIDSSNNLAVLKILEAseRDEGS 86

                          90       100
                  ....*....|....*....|....*...
gi 1973619857  86 YYC------QQRSNWPLTFGQGTKLEIK 107
Cdd:cd20988    87 YYCasdtpgGGREYDPLIFGKGTYLTVE 114

Immunoglobulin (Ig)-like variable (V) domain of the Signal-Regulatory Protein (SIRP); The members here are composed of the immunoglobulin (Ig)-like domain of the Signal-Regulatory Protein (SIRP). The SIRPs belong to the "paired receptors" class of membrane proteins that comprise several genes coding for proteins with similar extracellular regions, but very different transmembrane/cytoplasmic regions with different (activating or inhibitory) signaling potentials. They are commonly on NK cells, but are also on many myeloid cells. Their extracellular region contains three immunoglobulin superfamily domains, a single V-set, and two C1-set IgSF domains. Their cytoplasmic tails that contain either ITIMs or transmembrane regions have positively charged residues that allow an association with adaptor proteins, such as DAP12/KARAP, containing ITAMs. There are 3 distinct SIRP members: alpha, beta, and gamma. SIRP alpha (also known as CD172a or SRC homology 2 domain-containing protein tyrosine phosphatase substrate 1/Shps-1) is a membrane receptor that interacts with a ligand CD47 expressed on many cells and gives an inhibitory signal through immunoreceptor tyrosine-based inhibition motifs in the cytoplasmic region that interact with phosphatases SHP-1 and SHP-2. SIRP beta has a short cytoplasmic region and associates with a transmembrane adapter protein DAP12 containing immunoreceptor tyrosine-based activation motifs to give an activating signal. SIRP gamma contains a very short cytoplasmic region lacking obvious signaling motifs, but also binds CD47 with much less affinity. Members of this group contain standard Ig superfamily V-set AGFCC'C"/DEB domain topology.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1973619857   4 LTQSPGTLSLSPGERATLSCrasqSVSSYLA-----W-----------YQQKPGQAPRLL-IFDASIRatgiparfsgsg 66
Cdd:cd16097     2 VIQPEKSVSVAAGESATLHC----TVTSLIPvgpiqWfrgagpgreliYNQKEGHFPRVTtVSDLTKR------------ 65

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|....*.
gi 1973619857  67 SGTDFTLTISSLEPEDFAVYYCQQ-RSNWP----LTFGQGTKLEIK 107
Cdd:cd16097    66 NNMDFSIRISNITPADAGTYYCVKfRKGSPddveFKSGAGTELSVR 111

Immunoglobulin domain; The members here are composed of the immunoglobulin (Ig) domain found in the Ig superfamily. The Ig superfamily is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. Members of this group are components of immunoglobulin, neuroglia, cell surface glycoproteins, including T-cell receptors, CD2, CD4, CD8, and membrane glycoproteins, including butyrophilin and chondroitin sulfate proteoglycan core protein. A predominant feature of most Ig domains is a disulfide bridge connecting the two beta-sheets with a tryptophan residue packed against the disulfide bond. Ig superfamily (IgSF) domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. Typically, the V-set domains have A, B, E, and D strands in one sheet and A', G, F, C, C' and C" in the other. The structures in C1-set are smaller than those in the V-set; they have one beta sheet that is formed by strands A, B, E, and D and the other by strands G, F, C, and C'. Moreover, a C1-set Ig domain contains a short C' strand (three residues) and lacks A' and C" strand. Unlike other Ig domain sets, C2-set structures do not have a D strand. Like the V-set Ig domains, members of the I-set have a discontinuous A strand, but lack a C" strand.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 1973619857  19 ATLSCRASQSVSSYLAWYqqKPGQaprllifdaSIRATGIPARFSGSGSGTdftLTISSLEPEDFAVYYCQ 89
Cdd:cd00096     1 VTLTCSASGNPPPTITWY--KNGK---------PLPPSSRDSRRSELGNGT---LTISNVTLEDSGTYTCV 57