ID   CRYAB_ANAPL             Reviewed;         174 AA.
AC   Q05557;
DT   01-JUN-1994, integrated into UniProtKB/Swiss-Prot.
DT   01-JUN-1994, sequence version 1.
DT   03-AUG-2022, entry version 115.
DE   RecName: Full=Alpha-crystallin B chain;
DE   AltName: Full=Alpha(B)-crystallin;
GN   Name=CRYAB;
OS   Anas platyrhynchos (Mallard) (Anas boschas).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC   Archelosauria; Archosauria; Dinosauria; Saurischia; Theropoda;
OC   Coelurosauria; Aves; Neognathae; Galloanserae; Anseriformes; Anatidae;
OC   Anatinae; Anas.
OX   NCBI_TaxID=8839;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA].
RC   TISSUE=Lens;
RX   PubMed=8371274; DOI=10.1006/jmbi.1993.1476;
RA   Lee D.C., Kim R.Y., Wistow G.J.;
RT   "An avian alpha B-crystallin. Non-lens expression and sequence similarities
RT   with both small (HSP27) and large (HSP70) heat shock proteins.";
RL   J. Mol. Biol. 232:1221-1226(1993).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=7640300; DOI=10.1016/0167-4781(95)00087-w;
RA   Wistow G., Graham C.;
RT   "The duck gene for alpha B-crystallin shows evolutionary conservation of
RT   discrete promoter elements but lacks heat and osmotic shock response.";
RL   Biochim. Biophys. Acta 1263:105-113(1995).
CC   -!- FUNCTION: May contribute to the transparency and refractive index of
CC       the lens.
CC   -!- SUBUNIT: Heteromer composed of three CRYAA and one CRYAB subunits.
CC       Aggregates with homologous proteins, including the small heat shock
CC       protein HSPB1, to form large heteromeric complexes. Inter-subunit
CC       bridging via zinc ions enhances stability, which is crucial as there is
CC       no protein turn over in the lens (By similarity). {ECO:0000250}.
CC   -!- TISSUE SPECIFICITY: Lens as well as other tissues.
CC   -!- SIMILARITY: Belongs to the small heat shock protein (HSP20) family.
CC       {ECO:0000255|PROSITE-ProRule:PRU00285}.
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DR   EMBL; L08078; AAA02969.1; -; mRNA.
DR   EMBL; U16124; AAA86978.1; -; Genomic_DNA.
DR   PIR; S58758; S58758.
DR   RefSeq; NP_001297295.1; NM_001310366.1.
DR   AlphaFoldDB; Q05557; -.
DR   SMR; Q05557; -.
DR   Ensembl; ENSAPLT00020004083; ENSAPLP00020003794; ENSAPLG00020002808.
DR   GeneID; 101800794; -.
DR   KEGG; apla:101800794; -.
DR   CTD; 1410; -.
DR   HOGENOM; CLU_095001_2_0_1; -.
DR   OMA; RPSFMRW; -.
DR   OrthoDB; 1187096at2759; -.
DR   GO; GO:0046872; F:metal ion binding; IEA:UniProtKB-KW.
DR   GO; GO:0042803; F:protein homodimerization activity; ISS:UniProtKB.
DR   GO; GO:0005212; F:structural constituent of eye lens; IEA:UniProtKB-KW.
DR   Gene3D; 2.60.40.790; -; 1.
DR   InterPro; IPR002068; A-crystallin/Hsp20_dom.
DR   InterPro; IPR001436; Alpha-crystallin/sHSP_animal.
DR   InterPro; IPR003090; Alpha-crystallin_N.
DR   InterPro; IPR008978; HSP20-like_chaperone.
DR   PANTHER; PTHR45640; PTHR45640; 1.
DR   Pfam; PF00525; Crystallin; 1.
DR   Pfam; PF00011; HSP20; 1.
DR   PIRSF; PIRSF036514; Sm_HSP_B1; 1.
DR   PRINTS; PR00299; ACRYSTALLIN.
DR   SUPFAM; SSF49764; SSF49764; 1.
DR   PROSITE; PS01031; SHSP; 1.
PE   2: Evidence at transcript level;
KW   Acetylation; Eye lens protein; Metal-binding; Zinc.
FT   CHAIN           1..174
FT                   /note="Alpha-crystallin B chain"
FT                   /id="PRO_0000125916"
FT   DOMAIN          55..163
FT                   /note="sHSP"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00285"
FT   REGION          148..174
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        155..174
FT                   /note="Basic and acidic residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   BINDING         82
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_label="1"
FT                   /evidence="ECO:0000250"
FT   BINDING         103
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_label="2"
FT                   /evidence="ECO:0000250"
FT   BINDING         105
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_label="2"
FT                   /evidence="ECO:0000250"
FT   BINDING         110
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_label="1"
FT                   /evidence="ECO:0000250"
FT   MOD_RES         1
FT                   /note="N-acetylmethionine"
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   174 AA;  19937 MW;  8867208FDEAB7D6E CRC64;
     MDITIHNPLI RRPLFSWLAP SRIFDQIFGE HLQESELLPA SPSLSPFLMR SPIFRMPSWL
     ETGLSEMRLE KDKFSVNLDV KHFSPEELKV KVLGDMVEIH GKHEERQDEH GFIAREFNRK
     YRIPADVDPL TITSSLSLDG VLTVSAPRKQ SDVPERSIPI TREEKPAIAG AQRK