ID   VKT_NAJAT               Reviewed;          81 AA.
AC   Q5ZPJ7;
DT   16-JUN-2009, integrated into UniProtKB/Swiss-Prot.
DT   23-NOV-2004, sequence version 1.
DT   25-MAY-2022, entry version 53.
DE   RecName: Full=Kunitz-type serine protease inhibitor NACI;
DE   AltName: Full=Naja atra chymotrypsin inhibitor;
DE            Short=ACI;
DE            Short=NA-CI;
DE   Flags: Precursor;
OS   Naja atra (Chinese cobra).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC   Lepidosauria; Squamata; Bifurcata; Unidentata; Episquamata; Toxicofera;
OC   Serpentes; Colubroidea; Elapidae; Elapinae; Naja.
OX   NCBI_TaxID=8656;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA / MRNA], AND FUNCTION.
RC   TISSUE=Liver, and Venom gland;
RX   PubMed=15698956; DOI=10.1016/j.bbapap.2004.11.006;
RA   Cheng Y.-C., Yan F.-J., Chang L.-S.;
RT   "Taiwan cobra chymotrypsin inhibitor: cloning, functional expression and
RT   gene organization.";
RL   Biochim. Biophys. Acta 1747:213-220(2005).
RN   [2]
RP   PROTEIN SEQUENCE OF 25-81, FUNCTION, AND MASS SPECTROMETRY.
RC   TISSUE=Venom;
RX   PubMed=14990218; DOI=10.1016/j.cbpc.2003.11.007;
RA   Zhou X.D., Jin Y., Lu Q.M., Li D.S., Zhu S.W., Wang W.Y., Xiong Y.L.;
RT   "Purification, characterization and primary structure of a chymotrypsin
RT   inhibitor from Naja atra venom.";
RL   Comp. Biochem. Physiol. 137:219-224(2004).
RN   [3]
RP   STRUCTURE BY NMR OF 25-81, AND DISULFIDE BONDS.
RX   PubMed=23896616; DOI=10.3390/molecules18088906;
RA   Lin Y.J., Ikeya T., Guntert P., Chang L.S.;
RT   "NMR solution structure of a chymotrypsin inhibitor from the Taiwan cobra
RT   Naja naja atra.";
RL   Molecules 18:8906-8918(2013).
CC   -!- FUNCTION: Serine protease inhibitor that inhibits chymotrypsin (Ki=25
CC       nM). {ECO:0000269|PubMed:14990218, ECO:0000269|PubMed:15698956}.
CC   -!- SUBCELLULAR LOCATION: Secreted.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC   -!- MASS SPECTROMETRY: Mass=6403.8; Method=MALDI;
CC       Evidence={ECO:0000269|PubMed:15698956};
CC   -!- SIMILARITY: Belongs to the venom Kunitz-type family. {ECO:0000305}.
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DR   EMBL; AJ586046; CAE51866.1; -; mRNA.
DR   EMBL; AJ586047; CAE51867.1; -; Genomic_DNA.
DR   PDB; 2M99; NMR; -; A=25-81.
DR   PDBsum; 2M99; -.
DR   AlphaFoldDB; Q5ZPJ7; -.
DR   BMRB; Q5ZPJ7; -.
DR   SMR; Q5ZPJ7; -.
DR   MEROPS; I02.065; -.
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; cd00109; KU; 1.
DR   Gene3D; 4.10.410.10; -; 1.
DR   InterPro; IPR002223; Kunitz_BPTI.
DR   InterPro; IPR036880; Kunitz_BPTI_sf.
DR   InterPro; IPR020901; Prtase_inh_Kunz-CS.
DR   Pfam; PF00014; Kunitz_BPTI; 1.
DR   PRINTS; PR00759; BASICPTASE.
DR   SMART; SM00131; KU; 1.
DR   SUPFAM; SSF57362; SSF57362; 1.
DR   PROSITE; PS00280; BPTI_KUNITZ_1; 1.
DR   PROSITE; PS50279; BPTI_KUNITZ_2; 1.
PE   1: Evidence at protein level;
KW   3D-structure; Direct protein sequencing; Disulfide bond; Glycoprotein;
KW   Protease inhibitor; Secreted; Serine protease inhibitor; Signal.
FT   SIGNAL          1..24
FT                   /evidence="ECO:0000250"
FT   CHAIN           25..81
FT                   /note="Kunitz-type serine protease inhibitor NACI"
FT                   /id="PRO_5000072173"
FT   DOMAIN          29..79
FT                   /note="BPTI/Kunitz inhibitor"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00031"
FT   SITE            39..40
FT                   /note="Reactive bond for chymotrypsin"
FT                   /evidence="ECO:0000250"
FT   CARBOHYD        76
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255"
FT   DISULFID        29..79
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00031,
FT                   ECO:0000269|PubMed:23896616"
FT   DISULFID        38..62
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00031,
FT                   ECO:0000269|PubMed:23896616"
FT   DISULFID        54..75
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00031,
FT                   ECO:0000269|PubMed:23896616"
FT   HELIX           27..30
FT                   /evidence="ECO:0007829|PDB:2M99"
FT   HELIX           35..37
FT                   /evidence="ECO:0007829|PDB:2M99"
FT   STRAND          42..48
FT                   /evidence="ECO:0007829|PDB:2M99"
FT   HELIX           49..51
FT                   /evidence="ECO:0007829|PDB:2M99"
FT   STRAND          53..59
FT                   /evidence="ECO:0007829|PDB:2M99"
FT   STRAND          61..63
FT                   /evidence="ECO:0007829|PDB:2M99"
FT   HELIX           72..79
FT                   /evidence="ECO:0007829|PDB:2M99"
SQ   SEQUENCE   81 AA;  8815 MW;  520251DBA713040C CRC64;
     MSSGGLLLLL GLLTLWAELT PVSGRPRFCE LAPSAGSCFA FVPSYYYNQY SNTCHSFTYS
     GCGGNANRFR TIDECNRTCV G