ID   ITR3_MOMCO              Reviewed;          30 AA.
AC   P82410;
DT   01-DEC-2000, integrated into UniProtKB/Swiss-Prot.
DT   01-JUN-2000, sequence version 1.
DT   25-MAY-2022, entry version 87.
DE   RecName: Full=Trypsin inhibitor 3;
DE   AltName: Full=MCoTI-III;
DE   AltName: Full=Trypsin inhibitor III;
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, PYROGLUTAMATE FORMATION AT GLN-1, 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).
CC   -!- FUNCTION: Inhibits trypsin; probably participates in a plant defense
CC       mechanism.
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   -!- MASS SPECTROMETRY: Mass=3379.6; Mass_error=0.5; 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; 2LJS; NMR; -; A=1-30.
DR   PDBsum; 2LJS; -.
DR   AlphaFoldDB; P82410; -.
DR   SMR; P82410; -.
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: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   Protease inhibitor; Pyrrolidone carboxylic acid; Secreted;
KW   Serine protease inhibitor.
FT   PEPTIDE         1..30
FT                   /note="Trypsin inhibitor 3"
FT                   /id="PRO_0000044390"
FT   SITE            6..7
FT                   /note="Reactive bond"
FT   MOD_RES         1
FT                   /note="Pyrrolidone carboxylic acid"
FT                   /evidence="ECO:0000269|PubMed:10801322"
FT   DISULFID        4..21
FT                   /evidence="ECO:0000250"
FT   DISULFID        11..23
FT                   /evidence="ECO:0000250"
FT   DISULFID        17..29
FT                   /evidence="ECO:0000250"
FT   HELIX           14..16
FT                   /evidence="ECO:0007829|PDB:2LJS"
FT   STRAND          27..30
FT                   /evidence="ECO:0007829|PDB:2LJS"
SQ   SEQUENCE   30 AA;  3403 MW;  D5E13476B1A9AA6E CRC64;
     QRACPRILKK CRRDSDCPGE CICKENGYCG