Alpha-crystallin domain (ACD) of alpha-crystallin-type small(s) heat shock proteins (Hsps). sHsps are small stress induced proteins with monomeric masses between 12 -43 kDa, whose common feature is the Alpha-crystallin domain (ACD). sHsps are generally active as large oligomers consisting of multiple subunits, and are believed to be ATP-independent chaperones that prevent aggregation and are important in refolding in combination with other Hsps.

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                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1188294292  49 DIRETPEAFRIEAELPGMSKDDVKVTVQDGVLSIQGERKQEEETNDSKHHRvERIYGSFLRRFTLPENVDENSIRANFKD 128
Cdd:cd06464     1 DVYETDDAYVVEADLPGFKKEDIKVEVEDGVLTISGEREEEEEEEENYLRR-ERSYGSFSRSFRLPEDVDPDKIKASLEN 79

                  ....*....
gi 1188294292 129 GILSLTLTK 137
Cdd:cd06464    80 GVLTITLPK 88

Alpha-crystallin domain (ACD) of alpha-crystallin-type small(s) heat shock proteins (Hsps). sHsps are small stress induced proteins with monomeric masses between 12 -43 kDa, whose common feature is the Alpha-crystallin domain (ACD). sHsps are generally active as large oligomers consisting of multiple subunits, and are believed to be ATP-independent chaperones that prevent aggregation and are important in refolding in combination with other Hsps.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1188294292  49 DIRETPEAFRIEAELPGMSKDDVKVTVQDGVLSIQGERKQEEETNDSKHHRvERIYGSFLRRFTLPENVDENSIRANFKD 128
Cdd:cd06464     1 DVYETDDAYVVEADLPGFKKEDIKVEVEDGVLTISGEREEEEEEEENYLRR-ERSYGSFSRSFRLPEDVDPDKIKASLEN 79

                  ....*....
gi 1188294292 129 GILSLTLTK 137
Cdd:cd06464    80 GVLTITLPK 88

Alpha crystallin domain (ACD) found in Saccharomyces cerevisiae (Sc) small heat shock protein (Hsp)26 and similar proteins. sHsps are molecular chaperones that suppress protein aggregation and protect against cell stress, and are generally active as large oligomers consisting of multiple subunits. ScHsp26 is temperature-regulated, it switches from an inactive to a chaperone-active form upon elevation in temperature. It associates into large 24-mers storage forms which upon heat shock disassociate into dimers. These dimers initiate the interaction with non-native substrate proteins and re-assemble into large globular assemblies having one monomer of substrate bound per dimer. This group also contains Arabidopsis thaliana (Ath) Hsp15.7, a peroxisomal matrix protein which can complement the morphological phenotype of S. cerevisiae mutants deficient in Hsps26. AthHsp15.7 is minimally expressed under normal conditions and is strongly induced by heat and oxidative stress. Also belonging to this group is wheat HSP16.9 which differs in quaternary structure from the shell-type particles of ScHsp26, it assembles as a dodecameric double disc, with each disc organized as a trimer of dimers.

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                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1188294292  48 VDIRETPEAFRIEAELPGMSKDDVKVTVQDG-VLSIQGERKQEEETNDSKHHRVERIYGSFLRRFTLPENVDENSIRANF 126
Cdd:cd06472     2 VDWKETPEAHVFKADVPGVKKEDVKVEVEDGrVLRISGERKKEEEKKGDDWHRVERSSGRFVRRFRLPENADADEVKAFL 81

                          90
                  ....*....|.
gi 1188294292 127 KDGILSLTLTK 137
Cdd:cd06472    82 ENGVLTVTVPK 92

This domain family includes the alpha-crystallin domain (ACD) of alpha-crystallin-type small heat shock proteins (sHsps) and a similar domain found in p23-like proteins. sHsps are small stress induced proteins with monomeric masses between 12 -43 kDa, whose common feature is this ACD. sHsps are generally active as large oligomers consisting of multiple subunits, and are believed to be ATP-independent chaperones that prevent aggregation and are important in refolding in combination with other Hsps. p23 is a cochaperone of the Hsp90 chaperoning pathway. It binds Hsp90 and participates in the folding of a number of Hsp90 clients including the progesterone receptor. p23 also has a passive chaperoning activity. p23 in addition may act as the cytosolic prostaglandin E2 synthase. Included in this family is the p23-like C-terminal CHORD-SGT1 (CS) domain of suppressor of G2 allele of Skp1 (Sgt1) and the p23-like domains of human butyrate-induced transcript 1 (hB-ind1), NUD (nuclear distribution) C, Melusin, and NAD(P)H cytochrome b5 (NCB5) oxidoreductase (OR).

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                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1188294292  50 IRETPEAFRIEAELPGMSKDDVKVTVQDGVLSIQGERKQEEEtndskhhrVERIYGSFLRRFTLPENVDENSIRANFKDG 129
Cdd:cd00298     1 WYQTDDEVVVTVDLPGVKKEDIKVEVEDNVLTISGKREEEEE--------RERSYGEFERSFELPEDVDPEKSKASLENG 72

                  ....*...
gi 1188294292 130 ILSLTLTK 137
Cdd:cd00298    73 VLEITLPK 80

Alpha-crystallin domain (ACD) found in Escherichia coli inclusion body-associated proteins IbpA and IbpB, and similar proteins. IbpA and IbpB are 16 kDa small heat shock proteins (sHsps). sHsps are molecular chaperones that suppress protein aggregation and protect against cell stress, and are generally active as large oligomers consisting of multiple subunits. IbpA and IbpB are produced during high-level production of various heterologous proteins, specifically human prorenin, renin and bovine insulin-like growth factor 2 (bIGF-2), and are strongly associated with inclusion bodies containing these heterologous proteins. IbpA and IbpB work as an integrated system to stabilize thermally aggregated proteins in a disaggregation competent state. The chaperone activity of IbpB is also significantly elevated as the temperature increases from normal to heat shock. The high temperature results in the disassociation of 2-3-MDa IbpB oligomers into smaller approximately 600-kDa structures. This elevated activity seen under heat shock conditions is retained for an extended period of time after the temperature is returned to normal. IbpA also forms multimers.

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                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1188294292  46 PAVDIRETPE-AFRIEAELPGMSKDDVKVTVQDGVLSIQGERKQEEETNDSKHHRvERIYGSFLRRFTLPENVDENsiRA 124
Cdd:cd06470     1 PPYNIEKTGEnNYRITLAVAGFSEDDLEIEVENNQLTVTGKKADEENEEREYLHR-GIAKRAFERSFNLADHVKVK--GA 77

                          90
                  ....*....|...
gi 1188294292 125 NFKDGILSLTLTK 137
Cdd:cd06470    78 ELENGLLTIDLER 90

Alpha-crystallin domain found in the small heat shock protein (sHsp) alphaA-crystallin (HspB4, 20kDa). sHsps are molecular chaperones that suppress protein aggregation and protect against cell stress, and are generally active as large oligomers consisting of multiple subunits. Alpha crystallin, an abundant protein in the mammalian lens, is a large (700 kDa) heteropolymer composed of HspB4 and HspB5, generally in a molar ratio of HspB4:HspB5 of 3:1. Only trace amounts of HspB4 are found in tissues other than the lens. HspB5 does not belong to this group. Mutations inHspB4 have been associated with Autosomal Dominant Congenital Cataract (ADCC). The chaperone-like functions of HspB4 are considered important for maintaining lens transparency and preventing cataract.

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                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1188294292  49 DIRETPEAFRIEAELPGMSKDDVKVTVQDGVLSIQGerKQEEETNDskHHRVERiygSFLRRFTLPENVDENSIRANFK- 127
Cdd:cd06497     4 EVRSDRDKFTIYLDVKHFSPEDLTVKVLDDYVEIHG--KHSERQDD--HGYISR---EFHRRYRLPSNVDQSAITCSLSa 76

                  ....*..
gi 1188294292 128 DGILSLT 134
Cdd:cd06497    77 DGMLTFS 83

Alpha crystallin domain (ACD) found in mammalian small heat shock protein (sHsp) HspB10, also known as sperm outer dense fiber protein (ODFP), and similar proteins. sHsps are molecular chaperones that suppress protein aggregation and protect against cell stress, and are generally active as large oligomers consisting of multiple subunits. Human (h) HspB10 occurs exclusively in the axoneme of sperm cells and may have a cytoskeletal role.

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                  ....*....|....*....|....*....|....*....|....*....|....*...
gi 1188294292  65 GMSKDDVKVTVQDGVLSIQGERKQEEETNDSKHHRveriYGSFLRRFTLPENVDENSI 122
Cdd:cd06482    18 GFEPDQVKVKVKDGKVQVSAERENRYDCLGSKKYS----YMNICKEFSLPPGVDEKDV 71

Alpha-crystallin domain found in the small heat shock protein (sHsp) alphaB-crystallin (HspB5, 20kDa). sHsps are molecular chaperones that suppress protein aggregation and protect against cell stress, and are generally active as large oligomers consisting of multiple subunits. Alpha crystallin, an abundant protein in the mammalian lens, is a large (700 kDa) heteropolymer composed of HspB4 and HspB5, generally in a molar ratio of HspB4:HspB5 of 3:1. HspB4 does not belong to this group. HspB5 shows increased synthesis in response to stress. HspB5 is also expressed constitutively in other tissues including brain, heart, and type I and type IIa skeletal muscle fibers, and in several cancers including gliomas, renal cell carcinomas, basal-like and metaplastic breast carcinomas, and head and neck cancer. Its functions include effects on the apoptotic pathway and on metastasis. Phosphorylation of HspB5 reduces its oligomerization and anti-apoptotic activities. HspB5 is protective in demyelinating disease such as multiple sclerosis (MS), being a negative regulator of inflammation. In early active MS lesions it is the most abundant gene transcript and an autoantigen, the immune response against it would disrupt its function and worsen inflammation and demyelination. Given as therapy for ongoing demyelinating disease it may counteract this effect. It is an autoantigen in the pathogenesis of various other inflammatory disorders including Lens-associated uveitis (LAU), and Behcet's disease. Mutations in HspB5 have been associated with diseases including dominant cataract and desmin-related myopathy.

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                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1188294292  49 DIRETPEAFRIEAELPGMSKDDVKVTVQDGVLSIQGerKQEEETNDskHHRVERiygSFLRRFTLPENVDENSIRANFK- 127
Cdd:cd06498     1 EMRLEKDKFSVNLDVKHFSPEELKVKVLGDFIEIHG--KHEERQDE--HGFISR---EFQRKYRIPADVDPLTITSSLSp 73

                  ....*..
gi 1188294292 128 DGILSLT 134
Cdd:cd06498    74 DGVLTVC 80