ID   CYVB_LEOCM              Reviewed;          28 AA.
AC   P84638;
DT   13-SEP-2005, integrated into UniProtKB/Swiss-Prot.
DT   13-SEP-2005, sequence version 1.
DT   25-MAY-2022, entry version 31.
DE   RecName: Full=Cycloviolin-B;
OS   Leonia cymosa (Sacha uba).
OC   Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta;
OC   Spermatophyta; Magnoliopsida; eudicotyledons; Gunneridae; Pentapetalae;
OC   rosids; fabids; Malpighiales; Violaceae; Leonia.
OX   NCBI_TaxID=341676;
RN   [1] {ECO:0000305}
RP   PROTEIN SEQUENCE, FUNCTION, AND MASS SPECTROMETRY.
RC   STRAIN=Q65T-5650 {ECO:0000269|PubMed:10813905};
RC   TISSUE=Bark {ECO:0000269|PubMed:10813905};
RX   PubMed=10813905; DOI=10.1021/jo990952r;
RA   Hallock Y.F., Sowder R.C. II, Pannell L.K., Hughes C.B., Johnson D.G.,
RA   Gulakowski R., Cardellina J.H. Jr., Boyd M.R.;
RT   "Cycloviolins A-D, anti-HIV macrocyclic peptides from Leonia cymosa.";
RL   J. Org. Chem. 65:124-128(2000).
CC   -!- FUNCTION: Probably participates in a plant defense mechanism. Has anti-
CC       HIV activity. {ECO:0000255|PROSITE-ProRule:PRU00395,
CC       ECO:0000269|PubMed:10813905, ECO:0000305}.
CC   -!- DOMAIN: The presence of a 'disulfide through disulfide knot'
CC       structurally defines this protein as a knottin.
CC       {ECO:0000250|UniProtKB:P56879}.
CC   -!- PTM: This is a cyclic peptide. {ECO:0000255|PROSITE-ProRule:PRU00395,
CC       ECO:0000269|PubMed:10813905}.
CC   -!- MASS SPECTROMETRY: Mass=2887.1; Method=FAB;
CC       Evidence={ECO:0000269|PubMed:10813905};
CC   -!- SIMILARITY: Belongs to the cyclotide family. {ECO:0000255|PROSITE-
CC       ProRule:PRU00395}.
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:0000305}.
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DR   AlphaFoldDB; P84638; -.
DR   SMR; P84638; -.
DR   GO; GO:0006952; P:defense response; IDA:UniProtKB.
DR   GO; GO:0050688; P:regulation of defense response to virus; IEA:UniProtKB-KW.
DR   InterPro; IPR005535; Cyclotide.
DR   InterPro; IPR036146; Cyclotide_sf.
DR   Pfam; PF03784; Cyclotide; 1.
DR   PIRSF; PIRSF037891; Cycloviolacin; 1.
DR   SUPFAM; SSF57038; SSF57038; 1.
DR   PROSITE; PS51052; CYCLOTIDE; 1.
PE   1: Evidence at protein level;
KW   Antiviral protein; Direct protein sequencing; Disulfide bond; Knottin;
KW   Plant defense.
FT   PEPTIDE         1..28
FT                   /note="Cycloviolin-B"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00395,
FT                   ECO:0000269|PubMed:10813905"
FT                   /id="PRO_0000043604"
FT   DISULFID        4..18
FT                   /evidence="ECO:0000250|UniProtKB:P56879,
FT                   ECO:0000255|PROSITE-ProRule:PRU00395"
FT   DISULFID        8..20
FT                   /evidence="ECO:0000250|UniProtKB:P56879,
FT                   ECO:0000255|PROSITE-ProRule:PRU00395"
FT   DISULFID        13..25
FT                   /evidence="ECO:0000250|UniProtKB:P56879,
FT                   ECO:0000255|PROSITE-ProRule:PRU00395"
FT   CROSSLNK        1..28
FT                   /note="Cyclopeptide (Gly-Asn)"
FT                   /evidence="ECO:0000269|PubMed:10813905"
SQ   SEQUENCE   28 AA;  2910 MW;  2E4E5CD5201411A4 CRC64;
     GTACGESCYV LPCFTVGCTC TSSQCFKN