ID   CRYAA_ALLMI             Reviewed;         173 AA.
AC   P06904;
DT   01-JAN-1988, integrated into UniProtKB/Swiss-Prot.
DT   01-JAN-1988, sequence version 1.
DT   03-AUG-2022, entry version 88.
DE   RecName: Full=Alpha-crystallin A chain;
GN   Name=CRYAA;
OS   Alligator mississippiensis (American alligator).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC   Archelosauria; Archosauria; Crocodylia; Alligatoridae; Alligatorinae;
OC   Alligator.
OX   NCBI_TaxID=8496;
RN   [1]
RP   PARTIAL PROTEIN SEQUENCE, AND ACETYLATION AT MET-1.
RX   PubMed=3870872; DOI=10.1093/oxfordjournals.molbev.a040367;
RA   de Jong W.W., Zweers A., Versteeg M., Dessauer H.C., Goodman M.;
RT   "Alpha-crystallin A sequences of Alligator mississippiensis and the lizard
RT   Tupinambis teguixin: molecular evolution and reptilian phylogeny.";
RL   Mol. Biol. Evol. 2:484-493(1985).
CC   -!- FUNCTION: Contributes to the transparency and refractive index of the
CC       lens. May act as a chaperone, preventing aggregation of various
CC       proteins under a wide range of stress conditions.
CC       {ECO:0000250|UniProtKB:P02489}.
CC   -!- SUBUNIT: Heteropolymer composed of three CRYAA and one CRYAB subunits
CC       (By similarity). Inter-subunit bridging via zinc ions enhances
CC       stability, which is crucial as there is no protein turn over in the
CC       lens. Can also form homodimers and homotetramers (dimers of dimers)
CC       which serve as the building blocks of homooligomers (By similarity).
CC       Within homooligomers, the zinc-binding motif is created from residues
CC       of 3 different molecules. His-100 and Glu-102 from one molecule are
CC       ligands of the zinc ion, and His-107 and His-154 residues from
CC       additional molecules complete the site with tetrahedral coordination
CC       geometry (By similarity). {ECO:0000250|UniProtKB:P02470,
CC       ECO:0000250|UniProtKB:P02489}.
CC   -!- SUBCELLULAR LOCATION: Cytoplasm {ECO:0000250|UniProtKB:P02489}. Nucleus
CC       {ECO:0000250|UniProtKB:P02489}. Note=Translocates to the nucleus during
CC       heat shock. {ECO:0000250|UniProtKB:P02489}.
CC   -!- SIMILARITY: Belongs to the small heat shock protein (HSP20) family.
CC       {ECO:0000255|PROSITE-ProRule:PRU00285}.
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DR   PIR; A25753; CYAQAA.
DR   AlphaFoldDB; P06904; -.
DR   SMR; P06904; -.
DR   STRING; 8496.XP_006260023.1; -.
DR   iPTMnet; P06904; -.
DR   eggNOG; KOG3591; Eukaryota.
DR   GO; GO:0005737; C:cytoplasm; IEA:UniProtKB-SubCell.
DR   GO; GO:0005634; C:nucleus; IEA:UniProtKB-SubCell.
DR   GO; GO:0046872; F:metal ion binding; IEA:UniProtKB-KW.
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; IPR012274; Alpha-crystallin_A.
DR   InterPro; IPR003090; Alpha-crystallin_N.
DR   InterPro; IPR008978; HSP20-like_chaperone.
DR   PANTHER; PTHR45640; PTHR45640; 1.
DR   PANTHER; PTHR45640:SF14; PTHR45640:SF14; 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   1: Evidence at protein level;
KW   Acetylation; Cytoplasm; Direct protein sequencing; Eye lens protein;
KW   Metal-binding; Nucleus; Zinc.
FT   CHAIN           1..173
FT                   /note="Alpha-crystallin A chain"
FT                   /id="PRO_0000125897"
FT   DOMAIN          52..164
FT                   /note="sHSP"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00285"
FT   REGION          152..173
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   BINDING         100
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_label="1"
FT                   /evidence="ECO:0000250|UniProtKB:P02470"
FT   BINDING         102
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_label="1"
FT                   /evidence="ECO:0000250|UniProtKB:P02470"
FT   BINDING         107
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_label="2"
FT                   /evidence="ECO:0000250|UniProtKB:P02470"
FT   BINDING         154
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_label="3"
FT                   /evidence="ECO:0000250|UniProtKB:P02470"
FT   MOD_RES         1
FT                   /note="N-acetylmethionine"
FT                   /evidence="ECO:0000269|PubMed:3870872"
SQ   SEQUENCE   173 AA;  19769 MW;  9B90D0B549BD2C2A CRC64;
     MDITIQHPWF KRALGPLIPS RLFDQFFGEG LFEYDLLPLL SSTISPYYRH SLFRSVLESG
     ISEVRSDRDK FTIMLDVKHF SPEDLSVKII DDFVEVHGKH NERQDDHGYI SREFHRRYRL
     PSSVDQSAVT CVLSADGMLT FSGSKVQSNV DTIHSDRPIP VAREEKPTSA PSS