ID   IBB_VIGUC               Reviewed;          76 AA.
AC   Q9S9E3;
DT   19-JUL-2004, integrated into UniProtKB/Swiss-Prot.
DT   01-MAY-2000, sequence version 1.
DT   25-MAY-2022, entry version 75.
DE   RecName: Full=Horsegram inhibitor 1;
DE   AltName: Full=Bowman-Birk type proteinase inhibitor HGI-I;
DE   AltName: Full=Horsegram inhibitor I;
DE   Contains:
DE     RecName: Full=Horsegram germinated inhibitor 1;
DE     AltName: Full=Horsegram germinated inhibitor I;
DE              Short=HGGI-I;
DE   Contains:
DE     RecName: Full=Horsegram germinated inhibitor 2;
DE     AltName: Full=Horsegram germinated inhibitor II;
DE              Short=HGGI-II;
DE   Contains:
DE     RecName: Full=Horsegram germinated inhibitor 3;
DE     AltName: Full=Horsegram germinated inhibitor III;
DE              Short=HGGI-III;
OS   Vigna unguiculata subsp. cylindrica (Horse gram) (Dolichos biflorus).
OC   Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta;
OC   Spermatophyta; Magnoliopsida; eudicotyledons; Gunneridae; Pentapetalae;
OC   rosids; fabids; Fabales; Fabaceae; Papilionoideae; 50 kb inversion clade;
OC   NPAAA clade; indigoferoid/millettioid clade; Phaseoleae; Vigna.
OX   NCBI_TaxID=3840;
RN   [1] {ECO:0000305}
RP   PROTEIN SEQUENCE, AND IDENTIFICATION BY MASS SPECTROMETRY.
RC   TISSUE=Seed {ECO:0000269|PubMed:8662008};
RX   PubMed=8662008; DOI=10.1007/bf02352286;
RA   Prakash B., Selvaraj S., Murthy M.R.N., Sreerama Y.N., Rao D.R.,
RA   Gowda L.R.;
RT   "Analysis of the amino acid sequences of plant Bowman-Birk inhibitors.";
RL   J. Mol. Evol. 42:560-569(1996).
RN   [2] {ECO:0000305}
RP   PROTEIN SEQUENCE, AND REACTIVE SITES.
RC   TISSUE=Seed {ECO:0000269|PubMed:9434114};
RX   PubMed=9434114; DOI=10.1016/s0167-4838(97)00117-9;
RA   Sreerama Y.N., Gowda L.R.;
RT   "Antigenic determinants and reactive sites of a trypsin/chymotrypsin
RT   double-headed inhibitor from horse gram (Dolichos biflorus).";
RL   Biochim. Biophys. Acta 1343:235-242(1997).
RN   [3] {ECO:0000305}
RP   PROTEIN SEQUENCE (HGI-III; HGGI-I; HGGI-II AND HGGI-III), SUBUNIT, AND
RP   VARIANT ALA-21.
RC   TISSUE=Seed {ECO:0000269|PubMed:15123729};
RX   PubMed=15123729; DOI=10.1074/jbc.m402972200;
RA   Kumar P., Roa A.G.A., Hariharaputran S., Chandra N., Gowda L.R.;
RT   "Molecular mechanism of dimerization of Bowman-Birk inhibitors: pivotal
RT   role of Asp76 in the dimerization.";
RL   J. Biol. Chem. 279:30425-30432(2004).
RN   [4] {ECO:0000305}
RP   PROTEIN SEQUENCE OF 1-21, FUNCTION, SUBUNIT, AND MASS SPECTROMETRY.
RC   TISSUE=Seed {ECO:0000269|Ref.4};
RX   AGRICOLA=IND21240931; DOI=10.1111/j.1745-4514.1997.tb00200.x;
RA   Sreerama Y.N., Das J.R., Rao D.R., Gowda L.R.;
RT   "Double-headed trypsin/chymotrypsin inhibitors from horse gram (Dolichos
RT   biflorus): purification, molecular and kinetic properties.";
RL   J. Food Biochem. 21:461-477(1997).
RN   [5] {ECO:0000305}
RP   PARTIAL PROTEIN SEQUENCE (HGGI-I; HGGI-II AND HGGI-III), FUNCTION,
RP   DEVELOPMENTAL STAGE, AND MASS SPECTROMETRY.
RC   TISSUE=Seed {ECO:0000269|PubMed:12126704};
RX   PubMed=12126704; DOI=10.1016/s0031-9422(02)00178-4;
RA   Kumar P., Sreerama Y.N., Gowda L.R.;
RT   "Formation of Bowman-Birk inhibitors during the germination of horsegram
RT   (Dolichos biflorus).";
RL   Phytochemistry 60:581-588(2002).
RN   [6] {ECO:0000305}
RP   DEVELOPMENTAL STAGE.
RC   TISSUE=Seed {ECO:0000269|Ref.6};
RA   Sreerama Y.N., Gowda L.R.;
RT   "Bowman-Birk type proteinase inhibitor profiles of horse gram (Dolichos
RT   biflorus) during germintation and seed development.";
RL   J. Agric. Food Chem. 46:2596-2600(1998).
CC   -!- FUNCTION: Inhibitors of trypsin and chymotrypsin. HGGI-III has a higher
CC       activity than HGGI-I or HGGI-II. {ECO:0000269|PubMed:12126704,
CC       ECO:0000269|Ref.4}.
CC   -!- SUBUNIT: HGI-III exists in a state of equilibrium between monomer,
CC       homodimer and trimer, with homodimer being the predominant form. The
CC       homodimer is stabilized by the non-covalent interaction between Lys-24
CC       of one subunit and Asp-76 of the other subunit. The homodimer is more
CC       thermostable than the monomer. HGGI-I, HGGI-II and HGGI-III exist as
CC       monomers. {ECO:0000269|PubMed:15123729, ECO:0000269|Ref.4}.
CC   -!- DEVELOPMENTAL STAGE: HGI-III is expressed before germination. HGGI-I,
CC       HGGI-II and HGGI-III are expressed after germination.
CC       {ECO:0000269|PubMed:12126704, ECO:0000269|Ref.6}.
CC   -!- PTM: HGGI-I, HGGI-II and HGGI-III are produced by proteolysis of the
CC       N- and C-termini of HGI-III. {ECO:0000303|PubMed:12126704,
CC       ECO:0000303|Ref.6}.
CC   -!- MASS SPECTROMETRY: [Horsegram inhibitor 1]: Mass=8625;
CC       Method=Electrospray; Evidence={ECO:0000269|Ref.4};
CC   -!- MASS SPECTROMETRY: [Horsegram germinated inhibitor 1]: Mass=7216.7;
CC       Method=MALDI; Evidence={ECO:0000269|PubMed:12126704};
CC   -!- MASS SPECTROMETRY: [Horsegram germinated inhibitor 2]: Mass=7074.6;
CC       Method=MALDI; Evidence={ECO:0000269|PubMed:12126704};
CC   -!- MASS SPECTROMETRY: [Horsegram germinated inhibitor 3]: Mass=6493.5;
CC       Method=MALDI; Evidence={ECO:0000269|PubMed:12126704};
CC   -!- SIMILARITY: Belongs to the Bowman-Birk serine protease inhibitor
CC       family. {ECO:0000255}.
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DR   PDB; 6E5M; X-ray; 1.61 A; I=22-30.
DR   PDB; 6EAT; X-ray; 1.15 A; I=22-30.
DR   PDBsum; 6E5M; -.
DR   PDBsum; 6EAT; -.
DR   AlphaFoldDB; Q9S9E3; -.
DR   SMR; Q9S9E3; -.
DR   GO; GO:0005576; C:extracellular region; IEA:InterPro.
DR   GO; GO:0004867; F:serine-type endopeptidase inhibitor activity; IEA:UniProtKB-KW.
DR   CDD; cd00023; BBI; 1.
DR   Gene3D; 2.10.69.10; -; 1.
DR   InterPro; IPR035995; Bowman-Birk_prot_inh.
DR   InterPro; IPR000877; Prot_inh_BBI.
DR   Pfam; PF00228; Bowman-Birk_leg; 1.
DR   SMART; SM00269; BowB; 1.
DR   SUPFAM; SSF57247; SSF57247; 1.
DR   PROSITE; PS00281; BOWMAN_BIRK; 1.
PE   1: Evidence at protein level;
KW   3D-structure; Direct protein sequencing; Disulfide bond;
KW   Protease inhibitor; Serine protease inhibitor.
FT   CHAIN           1..76
FT                   /note="Horsegram inhibitor 1"
FT                   /id="PRO_0000003264"
FT   CHAIN           7..72
FT                   /note="Horsegram germinated inhibitor 1"
FT                   /id="PRO_0000003265"
FT   CHAIN           8..72
FT                   /note="Horsegram germinated inhibitor 2"
FT                   /id="PRO_0000003266"
FT   CHAIN           13..72
FT                   /note="Horsegram germinated inhibitor 3"
FT                   /id="PRO_0000003267"
FT   SITE            24..25
FT                   /note="Reactive bond for trypsin"
FT   SITE            51..52
FT                   /note="Reactive bond for chymotrypsin"
FT   DISULFID        16..70
FT                   /evidence="ECO:0000250|UniProtKB:P01058"
FT   DISULFID        17..32
FT                   /evidence="ECO:0000250|UniProtKB:P01058"
FT   DISULFID        20..66
FT                   /evidence="ECO:0000250|UniProtKB:P01058"
FT   DISULFID        22..30
FT                   /evidence="ECO:0000250|UniProtKB:P01058"
FT   DISULFID        40..47
FT                   /evidence="ECO:0000250|UniProtKB:P01058"
FT   DISULFID        44..59
FT                   /evidence="ECO:0000250|UniProtKB:P01058"
FT   DISULFID        49..57
FT                   /evidence="ECO:0000250|UniProtKB:P01058"
FT   VARIANT         21
FT                   /note="T -> A (in HGGI-I, HGGI-II and HGGI-III)"
FT                   /evidence="ECO:0000269|PubMed:15123729"
FT   STRAND          23..27
FT                   /evidence="ECO:0007829|PDB:6EAT"
SQ   SEQUENCE   76 AA;  8312 MW;  C13EC53C71BE4032 CRC64;
     DHHQSTDEPS ESSKPCCDQC TCTKSIPPQC RCTDVRLNSC HSACSSCVCT FSIPAQCVCV
     DMKDFCYAPC KSSHDD