ID   ITR2_ECBEL              Reviewed;          30 AA.
AC   P12071;
DT   01-OCT-1989, integrated into UniProtKB/Swiss-Prot.
DT   01-JUN-1994, sequence version 2.
DT   25-MAY-2022, entry version 106.
DE   RecName: Full=Trypsin inhibitor 2;
DE   AltName: Full=EETI-II;
DE   AltName: Full=Trypsin inhibitor II;
OS   Ecballium elaterium (Squirting cucumber) (Momordica elaterium).
OC   Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta;
OC   Spermatophyta; Magnoliopsida; eudicotyledons; Gunneridae; Pentapetalae;
OC   rosids; fabids; Cucurbitales; Cucurbitaceae; Bryonieae; Ecballium.
OX   NCBI_TaxID=3679;
RN   [1]
RP   PROTEIN SEQUENCE.
RC   TISSUE=Seed;
RX   PubMed=2654042; DOI=10.1111/j.1399-3011.1989.tb00210.x;
RA   Favel A., Mattras H., Coletti-Previero M.-A., Zwilling R., Robinson E.A.,
RA   Castro B.;
RT   "Protease inhibitors from Ecballium elaterium seeds.";
RL   Int. J. Pept. Protein Res. 33:202-208(1989).
RN   [2]
RP   STRUCTURE BY NMR.
RX   PubMed=2622910; DOI=10.1002/prot.340060407;
RA   Chiche L., Gaboriaud C., Heitz A., Mornon J.-P., Castro B., Kollman P.A.;
RT   "Use of restrained molecular dynamics in water to determine three-
RT   dimensional protein structure: prediction of the three-dimensional
RT   structure of Ecballium elaterium trypsin inhibitor II.";
RL   Proteins 6:405-417(1989).
RN   [3]
RP   STRUCTURE BY NMR OF MUTANT WITH CYS REPLACED BY SER.
RX   PubMed=8521849; DOI=10.1111/j.1432-1033.1995.837_3.x;
RA   Heitz A., Chiche L., Castro B.;
RT   "Folding of the squash trypsin inhibitor EETI II. Evidence of native and
RT   non-native local structural preferences in a linear analogue.";
RL   Eur. J. Biochem. 233:837-846(1995).
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.
CC   -!- SIMILARITY: Belongs to the protease inhibitor I7 (squash-type serine
CC       protease inhibitor) family. {ECO:0000305}.
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DR   PIR; JQ1958; JQ1958.
DR   PDB; 1H9H; X-ray; 1.50 A; I=1-30.
DR   PDB; 1H9I; X-ray; 1.90 A; I=1-30.
DR   PDB; 1W7Z; X-ray; 1.67 A; A/B/C/D/E/F/G/H=1-30.
DR   PDB; 2C4B; X-ray; 1.30 A; A/B=16-29.
DR   PDB; 2ETI; NMR; -; A=1-28.
DR   PDB; 2IT7; NMR; -; A=1-28.
DR   PDB; 2LET; NMR; -; A=1-28.
DR   PDB; 6MSL; X-ray; 3.10 A; C=9-28.
DR   PDB; 6MSU; X-ray; 3.11 A; C=2-28.
DR   PDBsum; 1H9H; -.
DR   PDBsum; 1H9I; -.
DR   PDBsum; 1W7Z; -.
DR   PDBsum; 2C4B; -.
DR   PDBsum; 2ETI; -.
DR   PDBsum; 2IT7; -.
DR   PDBsum; 2LET; -.
DR   PDBsum; 6MSL; -.
DR   PDBsum; 6MSU; -.
DR   AlphaFoldDB; P12071; -.
DR   BMRB; P12071; -.
DR   SMR; P12071; -.
DR   MEROPS; I07.003; -.
DR   EvolutionaryTrace; P12071; -.
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   3D-structure; Direct protein sequencing; Disulfide bond; Knottin;
KW   Protease inhibitor; Secreted; Serine protease inhibitor.
FT   PEPTIDE         1..30
FT                   /note="Trypsin inhibitor 2"
FT                   /id="PRO_0000044381"
FT   SITE            4..5
FT                   /note="Reactive bond"
FT   DISULFID        2..19
FT   DISULFID        9..21
FT   DISULFID        15..27
FT   STRAND          3..5
FT                   /evidence="ECO:0007829|PDB:2ETI"
FT   HELIX           12..14
FT                   /evidence="ECO:0007829|PDB:1W7Z"
FT   STRAND          25..28
FT                   /evidence="ECO:0007829|PDB:2C4B"
SQ   SEQUENCE   30 AA;  3089 MW;  BEE08D405B4AE17D CRC64;
     GCPRILMRCK QDSDCLAGCV CGPNGFCGSP