ID   ITR1_MOMCO              Reviewed;          34 AA.
AC   P82408;
DT   01-DEC-2000, integrated into UniProtKB/Swiss-Prot.
DT   01-JUN-2000, sequence version 1.
DT   03-AUG-2022, entry version 87.
DE   RecName: Full=Trypsin inhibitor 1 {ECO:0000305};
DE   AltName: Full=MCoTI-I {ECO:0000303|PubMed:10801322};
DE   AltName: Full=Trypsin inhibitor I {ECO:0000303|PubMed:10801322};
OS   Momordica cochinchinensis (Spiny bitter cucumber) (Muricia
OS   cochinchinensis).
OC   Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta;
OC   Spermatophyta; Magnoliopsida; eudicotyledons; Gunneridae; Pentapetalae;
OC   rosids; fabids; Cucurbitales; Cucurbitaceae; Momordiceae; Momordica.
OX   NCBI_TaxID=3674;
RN   [1]
RP   PROTEIN SEQUENCE, FUNCTION, CROSS-LINK, AND MASS SPECTROMETRY.
RC   TISSUE=Seed;
RX   PubMed=10801322; DOI=10.1021/bi9929756;
RA   Hernandez J.-F., Gagnon J., Chiche L., Nguyen T.M., Andrieu J.-P.,
RA   Heitz A., Trinh T., Pham T.T.C., Le Nguyen D.;
RT   "Squash trypsin inhibitors from Momordica cochinchinensis exhibit an
RT   atypical macrocyclic structure.";
RL   Biochemistry 39:5722-5730(2000).
RN   [2]
RP   X-RAY CRYSTALLOGRAPHY (1.00 ANGSTROMS) OF 11-34, AND DISULFIDE BONDS.
RX   PubMed=31611594; DOI=10.1038/s41467-019-11863-w;
RA   Kimura R.H., Wang L., Shen B., Huo L., Tummers W., Filipp F.V., Guo H.H.,
RA   Haywood T., Abou-Elkacem L., Baratto L., Habte F., Devulapally R.,
RA   Witney T.H., Cheng Y., Tikole S., Chakraborti S., Nix J., Bonagura C.A.,
RA   Hatami N., Mooney J.J., Desai T., Turner S., Gaster R.S., Otte A.,
RA   Visser B.C., Poultsides G.A., Norton J., Park W., Stolowitz M., Lau K.,
RA   Yang E., Natarajan A., Ilovich O., Srinivas S., Srinivasan A.,
RA   Paulmurugan R., Willmann J., Chin F.T., Cheng Z., Iagaru A., Li F.,
RA   Gambhir S.S.;
RT   "Evaluation of integrin alphavbeta6 cystine knot PET tracers to detect
RT   cancer and idiopathic pulmonary fibrosis.";
RL   Nat. Commun. 10:4673-4673(2019).
CC   -!- FUNCTION: Inhibits trypsin; probably participates in a plant defense
CC       mechanism. {ECO:0000305|PubMed:10801322}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000305}.
CC   -!- DOMAIN: The presence of a 'disulfide through disulfide knot'
CC       structurally defines this protein as a knottin. {ECO:0000250}.
CC   -!- PTM: This is a cyclic peptide. {ECO:0000269|PubMed:10801322}.
CC   -!- MASS SPECTROMETRY: Mass=3480.7; Mass_error=0.3; Method=Electrospray;
CC       Evidence={ECO:0000269|PubMed:10801322};
CC   -!- SIMILARITY: Belongs to the protease inhibitor I7 (squash-type serine
CC       protease inhibitor) family. {ECO:0000305}.
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DR   PDB; 6CDX; X-ray; 1.00 A; A/B=11-34.
DR   PDBsum; 6CDX; -.
DR   AlphaFoldDB; P82408; -.
DR   SMR; P82408; -.
DR   MEROPS; I07.004; -.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0004867; F:serine-type endopeptidase inhibitor activity; IDA:CAFA.
DR   GO; GO:0006952; P:defense response; IEA:UniProtKB-KW.
DR   GO; GO:1900004; P:negative regulation of serine-type endopeptidase activity; IDA:CAFA.
DR   CDD; cd00150; PlantTI; 1.
DR   InterPro; IPR000737; Prot_inh_squash.
DR   InterPro; IPR011052; Proteinase_amylase_inhib_sf.
DR   Pfam; PF00299; Squash; 1.
DR   SUPFAM; SSF57027; SSF57027; 1.
DR   PROSITE; PS00286; SQUASH_INHIBITOR; 1.
PE   1: Evidence at protein level;
KW   3D-structure; Direct protein sequencing; Disulfide bond; Knottin;
KW   Plant defense; Protease inhibitor; Secreted; Serine protease inhibitor.
FT   PEPTIDE         1..34
FT                   /note="Trypsin inhibitor 1"
FT                   /id="PRO_0000044857"
FT   SITE            10..11
FT                   /note="Reactive bond"
FT   DISULFID        8..25
FT                   /evidence="ECO:0000269|PubMed:31611594,
FT                   ECO:0007744|PDB:6CDX"
FT   DISULFID        15..27
FT                   /evidence="ECO:0000269|PubMed:31611594,
FT                   ECO:0007744|PDB:6CDX"
FT   DISULFID        21..33
FT                   /evidence="ECO:0000269|PubMed:31611594,
FT                   ECO:0007744|PDB:6CDX"
FT   CROSSLNK        1..34
FT                   /note="Cyclopeptide (Ser-Gly)"
FT                   /evidence="ECO:0000269|PubMed:10801322"
FT   HELIX           18..20
FT                   /evidence="ECO:0007829|PDB:6CDX"
FT   STRAND          31..34
FT                   /evidence="ECO:0007829|PDB:6CDX"
SQ   SEQUENCE   34 AA;  3505 MW;  8F7D0B4C162C935A CRC64;
     SGSDGGVCPK ILQRCRRDSD CPGACICRGN GYCG