ID   KAB8_OLDAF              Reviewed;          31 AA.
AC   P85175;
DT   10-JUL-2007, integrated into UniProtKB/Swiss-Prot.
DT   10-JUL-2007, sequence version 1.
DT   25-MAY-2022, entry version 40.
DE   RecName: Full=Kalata-B8;
OS   Oldenlandia affinis.
OC   Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta;
OC   Spermatophyta; Magnoliopsida; eudicotyledons; Gunneridae; Pentapetalae;
OC   asterids; lamiids; Gentianales; Rubiaceae; Rubioideae; Spermacoceae;
OC   Hedyotis-Oldenlandia complex; Oldenlandia.
OX   NCBI_TaxID=60225;
RN   [1] {ECO:0000305}
RP   PROTEIN SEQUENCE, STRUCTURE BY NMR, DISULFIDE BONDS, AND FUNCTION.
RX   PubMed=16207177; DOI=10.1042/bj20051371;
RA   Daly N.L., Clark R.J., Plan M.R.R., Craik D.J.;
RT   "Kalata B8, a novel antiviral circular protein, exhibits conformational
RT   flexibility in the cystine knot motif.";
RL   Biochem. J. 393:619-626(2006).
RN   [2] {ECO:0000305}
RP   PROTEIN SEQUENCE, AND MASS SPECTROMETRY.
RX   PubMed=17534989; DOI=10.1002/cbic.200700097;
RA   Plan M.R.R., Goeransson U., Clark R.J., Daly N.L., Colgrave M.L.,
RA   Craik D.J.;
RT   "The cyclotide fingerprint in Oldenlandia affinis: elucidation of
RT   chemically modified, linear and novel macrocyclic peptides.";
RL   ChemBioChem 8:1001-1011(2007).
CC   -!- FUNCTION: Probably participates in a plant defense mechanism. Inhibits
CC       the cytopathic effects of the human immunodeficiency virus. Has no
CC       hemolytic activity. {ECO:0000269|PubMed:16207177, ECO:0000305}.
CC   -!- DOMAIN: The presence of a 'disulfide through disulfide knot'
CC       structurally defines this protein as a knottin.
CC       {ECO:0000269|PubMed:16207177}.
CC   -!- PTM: This is a cyclic peptide. {ECO:0000269|PubMed:16207177,
CC       ECO:0000269|PubMed:17534989}.
CC   -!- MASS SPECTROMETRY: Mass=3283.8; Method=Electrospray;
CC       Evidence={ECO:0000269|PubMed:17534989};
CC   -!- SIMILARITY: Belongs to the cyclotide family. Bracelet subfamily.
CC       {ECO:0000269|PubMed:17534989}.
CC   -!- CAUTION: This peptide is cyclic. The start position was chosen by
CC       similarity to OAK1 (kalata-B1) for which the DNA sequence is known.
CC       {ECO:0000269|PubMed:16207177, ECO:0000269|PubMed:17534989}.
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DR   PDB; 2B38; NMR; -; A=6-31.
DR   PDBsum; 2B38; -.
DR   AlphaFoldDB; P85175; -.
DR   SMR; P85175; -.
DR   EvolutionaryTrace; P85175; -.
DR   GO; GO:0006952; P:defense response; IEA:UniProtKB-KW.
DR   InterPro; IPR005535; Cyclotide.
DR   InterPro; IPR036146; Cyclotide_sf.
DR   Pfam; PF03784; Cyclotide; 1.
DR   SUPFAM; SSF57038; SSF57038; 1.
PE   1: Evidence at protein level;
KW   3D-structure; Direct protein sequencing; Disulfide bond; Knottin;
KW   Plant defense.
FT   PEPTIDE         1..31
FT                   /note="Kalata-B8"
FT                   /evidence="ECO:0000269|PubMed:16207177"
FT                   /id="PRO_0000294955"
FT   DISULFID        6..20
FT                   /evidence="ECO:0000269|PubMed:16207177"
FT   DISULFID        10..22
FT                   /evidence="ECO:0000269|PubMed:16207177"
FT   DISULFID        15..28
FT                   /evidence="ECO:0000269|PubMed:16207177"
FT   CROSSLNK        1..31
FT                   /note="Cyclopeptide (Gly-Asp)"
FT                   /evidence="ECO:0000269|PubMed:16207177,
FT                   ECO:0000269|PubMed:17534989"
FT   STRAND          21..23
FT                   /evidence="ECO:0007829|PDB:2B38"
FT   TURN            24..26
FT                   /evidence="ECO:0007829|PDB:2B38"
FT   STRAND          27..31
FT                   /evidence="ECO:0007829|PDB:2B38"
SQ   SEQUENCE   31 AA;  3308 MW;  F41C424406EE82E8 CRC64;
     GSVLNCGETC LLGTCYTTGC TCNKYRVCTK D