ID   CYT1_CROAD              Reviewed;         139 AA.
AC   J3RYX9;
DT   24-JUL-2013, integrated into UniProtKB/Swiss-Prot.
DT   31-OCT-2012, sequence version 1.
DT   25-MAY-2022, entry version 20.
DE   RecName: Full=Cystatin-1;
DE   Flags: Precursor;
OS   Crotalus adamanteus (Eastern diamondback rattlesnake).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC   Lepidosauria; Squamata; Bifurcata; Unidentata; Episquamata; Toxicofera;
OC   Serpentes; Colubroidea; Viperidae; Crotalinae; Crotalus.
OX   NCBI_TaxID=8729;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA].
RC   TISSUE=Venom gland;
RX   PubMed=23025625; DOI=10.1186/1471-2164-13-312;
RA   Rokyta D.R., Lemmon A.R., Margres M.J., Aronow K.;
RT   "The venom-gland transcriptome of the eastern diamondback rattlesnake
RT   (Crotalus adamanteus).";
RL   BMC Genomics 13:312-312(2012).
CC   -!- FUNCTION: Inhibits various C1 cysteine proteases including cathepsin L,
CC       papain and cathepsin B. This protein has no toxic activity and its
CC       function in the venom is unknown. It may play a role as housekeeping or
CC       regulatory protein (By similarity). {ECO:0000250}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000250}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC   -!- SIMILARITY: Belongs to the cystatin family. {ECO:0000305}.
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DR   EMBL; JU174278; AFJ49804.1; -; mRNA.
DR   AlphaFoldDB; J3RYX9; -.
DR   SMR; J3RYX9; -.
DR   MEROPS; I25.012; -.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0004869; F:cysteine-type endopeptidase inhibitor activity; IEA:UniProtKB-KW.
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   2: Evidence at transcript level;
KW   Disulfide bond; Protease inhibitor; Secreted; Signal;
KW   Thiol protease inhibitor.
FT   SIGNAL          1..22
FT                   /evidence="ECO:0000255"
FT   CHAIN           23..139
FT                   /note="Cystatin-1"
FT                   /id="PRO_0000423038"
FT   DOMAIN          27..127
FT                   /note="Cystatin"
FT   MOTIF           71..75
FT                   /note="Secondary area of contact"
FT                   /evidence="ECO:0000250"
FT   SITE            27
FT                   /note="Reactive site"
FT                   /evidence="ECO:0000250"
FT   DISULFID        89..105
FT                   /evidence="ECO:0000250"
FT   DISULFID        118..138
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   139 AA;  15623 MW;  21ADDAB04F1FBC46 CRC64;
     MHSRLPVPAS LCLLLLLPSV LPASMPGGLS PRDVTDPEVQ EAAVFAVEEY NARSTNSNYF
     KALRLVQAES QVVSGAKYYL TMELVKTSCR KTNGNPKGYQ EIQNCRLPPR NQQEKLTCHF
     EVWSRPWLNK TLLTKVTCN