ID   CYT_ONCKE               Reviewed;         130 AA.
AC   Q98967;
DT   15-DEC-1998, integrated into UniProtKB/Swiss-Prot.
DT   15-DEC-1998, sequence version 2.
DT   25-MAY-2022, entry version 86.
DE   RecName: Full=Cystatin {ECO:0000303|PubMed:7764512};
DE   Flags: Precursor;
OS   Oncorhynchus keta (Chum salmon) (Salmo keta).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC   Actinopterygii; Neopterygii; Teleostei; Protacanthopterygii; Salmoniformes;
OC   Salmonidae; Salmoninae; Oncorhynchus.
OX   NCBI_TaxID=8018;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA], SYNTHETIC PEPTIDE 20-35, SUBCELLULAR LOCATION,
RP   AND TISSUE SPECIFICITY.
RC   TISSUE=Liver {ECO:0000303|PubMed:8902609};
RX   PubMed=8902609; DOI=10.1093/oxfordjournals.jbchem.a021438;
RA   Yamashita M., Konagaya S.;
RT   "Molecular cloning and gene expression of chum salmon cystatin.";
RL   J. Biochem. 120:483-487(1996).
RN   [2]
RP   PROTEIN SEQUENCE OF 20-130, FUNCTION, AND DISULFIDE BONDS.
RC   TISSUE=Pituitary {ECO:0000303|PubMed:7764512};
RX   PubMed=7764512; DOI=10.1271/bbb.58.164;
RA   Koide Y., Noso T.;
RT   "The complete amino acid sequence of pituitary cystatin from chum salmon.";
RL   Biosci. Biotechnol. Biochem. 58:164-169(1994).
CC   -!- FUNCTION: Cysteine proteinase inhibitor. {ECO:0000269|PubMed:7764512}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:8902609}.
CC   -!- TISSUE SPECIFICITY: Ubiquitous expression including brain, white
CC       muscle, heart, gill, kidney, spleen, liver and skin with the highest
CC       and lowest level in brain and gill, respectively.
CC       {ECO:0000269|PubMed:8902609}.
CC   -!- SIMILARITY: Belongs to the cystatin family. {ECO:0000305}.
CC   -!- SEQUENCE CAUTION:
CC       Sequence=BAA13149.1; Type=Erroneous initiation; Note=Extended N-terminus.; Evidence={ECO:0000305};
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DR   EMBL; D86628; BAA13149.1; ALT_INIT; mRNA.
DR   PIR; JC2040; JC2040.
DR   AlphaFoldDB; Q98967; -.
DR   SMR; Q98967; -.
DR   MEROPS; I25.041; -.
DR   GO; GO:0005576; C:extracellular region; IDA:UniProtKB.
DR   GO; GO:0004869; F:cysteine-type endopeptidase inhibitor activity; IEA:UniProtKB-KW.
DR   GO; GO:0030414; F:peptidase inhibitor activity; ISS:AgBase.
DR   CDD; cd00042; CY; 1.
DR   InterPro; IPR000010; Cystatin_dom.
DR   InterPro; IPR046350; Cystatin_sf.
DR   InterPro; IPR018073; Prot_inh_cystat_CS.
DR   Pfam; PF00031; Cystatin; 1.
DR   SMART; SM00043; CY; 1.
DR   SUPFAM; SSF54403; SSF54403; 1.
DR   PROSITE; PS00287; CYSTATIN; 1.
PE   1: Evidence at protein level;
KW   Direct protein sequencing; Disulfide bond; Protease inhibitor; Secreted;
KW   Signal; Thiol protease inhibitor.
FT   SIGNAL          1..19
FT                   /evidence="ECO:0000269|PubMed:7764512"
FT   CHAIN           20..130
FT                   /note="Cystatin"
FT                   /id="PRO_0000006665"
FT   MOTIF           67..71
FT                   /note="Secondary area of contact"
FT                   /evidence="ECO:0000250|UniProtKB:P04080"
FT   SITE            23
FT                   /note="Reactive site"
FT                   /evidence="ECO:0000250|UniProtKB:P04080"
FT   DISULFID        85..94
FT                   /evidence="ECO:0000269|PubMed:7764512"
FT   DISULFID        108..128
FT                   /evidence="ECO:0000269|PubMed:7764512"
FT   CONFLICT        22
FT                   /note="V -> I (in Ref. 2; AA sequence)"
FT                   /evidence="ECO:0000305"
FT   CONFLICT        115
FT                   /note="R -> I (in Ref. 2; AA sequence)"
FT                   /evidence="ECO:0000305"
FT   CONFLICT        120
FT                   /note="D -> G (in Ref. 2; AA sequence)"
FT                   /evidence="ECO:0000305"
FT   CONFLICT        122
FT                   /note="Q -> K (in Ref. 2; AA sequence)"
FT                   /evidence="ECO:0000305"
SQ   SEQUENCE   130 AA;  14566 MW;  099BBCC8A998C2D7 CRC64;
     MEWKIVVPLL AVAFTVANAG LVGGPMDANM NDQGTRDALQ FAVVEHNKKT NDMFVRQVAK
     VVNAQKQVVS GMKYIFTVQM GRTPCRKGGV EKICSVHKDP QMAVPYKCTF EVWSRPWMSD
     IQMVKNQCES