ID   ITR1_CITLA              Reviewed;          30 AA.
AC   P11969;
DT   01-OCT-1989, integrated into UniProtKB/Swiss-Prot.
DT   01-OCT-1989, sequence version 1.
DT   25-MAY-2022, entry version 86.
DE   RecName: Full=Trypsin inhibitor 1;
DE   AltName: Full=CVTI-I;
DE   AltName: Full=Trypsin inhibitor I;
OS   Citrullus lanatus (Watermelon) (Citrullus vulgaris).
OC   Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta;
OC   Spermatophyta; Magnoliopsida; eudicotyledons; Gunneridae; Pentapetalae;
OC   rosids; fabids; Cucurbitales; Cucurbitaceae; Benincaseae; Citrullus.
OX   NCBI_TaxID=3654;
RN   [1]
RP   PROTEIN SEQUENCE.
RC   TISSUE=Seed;
RX   PubMed=3435645; DOI=10.1515/bchm3.1987.368.2.1505;
RA   Otlewski J., Whatley H., Polanowski A., Wilusz T.;
RT   "Amino-acid sequences of trypsin inhibitors from watermelon (Citrullus
RT   vulgaris) and red bryony (Bryonia dioica) seeds.";
RL   Biol. Chem. Hoppe-Seyler 368:1505-1507(1987).
CC   -!- FUNCTION: Inhibits trypsin.
CC   -!- SUBCELLULAR LOCATION: Secreted.
CC   -!- DOMAIN: The presence of a 'disulfide through disulfide knot'
CC       structurally defines this protein as a knottin. {ECO:0000250}.
CC   -!- SIMILARITY: Belongs to the protease inhibitor I7 (squash-type serine
CC       protease inhibitor) family. {ECO:0000305}.
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DR   PIR; S00176; TIPU1W.
DR   AlphaFoldDB; P11969; -.
DR   SMR; P11969; -.
DR   MEROPS; I07.009; -.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0004867; F:serine-type endopeptidase inhibitor activity; IEA:UniProtKB-KW.
DR   CDD; cd00150; PlantTI; 1.
DR   InterPro; IPR000737; Prot_inh_squash.
DR   InterPro; IPR011052; Proteinase_amylase_inhib_sf.
DR   Pfam; PF00299; Squash; 1.
DR   PRINTS; PR00293; SQUASHINHBTR.
DR   SUPFAM; SSF57027; SSF57027; 1.
DR   PROSITE; PS00286; SQUASH_INHIBITOR; 1.
PE   1: Evidence at protein level;
KW   Direct protein sequencing; Disulfide bond; Knottin; Protease inhibitor;
KW   Secreted; Serine protease inhibitor.
FT   PEPTIDE         1..30
FT                   /note="Trypsin inhibitor 1"
FT                   /id="PRO_0000044375"
FT   SITE            6..7
FT                   /note="Reactive bond"
FT   DISULFID        4..21
FT                   /evidence="ECO:0000250"
FT   DISULFID        11..23
FT                   /evidence="ECO:0000250"
FT   DISULFID        17..29
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   30 AA;  3386 MW;  99A23C91FA486F3F CRC64;
     GRRCPRIYME CKRDADCLAD CVCLQHGICG