title: Cycloviolins A-D, anti-HIV macrocyclic peptides from Leonia cymosa.
abstract: Four novel anti-HIV macrocyclic peptides containing 28-31 amino acid residues, named cycloviolins A-D, have been isolated from the hitherto unstudied tropical plant Leonia cymosa. Their primary structure, including amino acid composition and sequence, was determined by a combination of MALDI-TOF and FAB MS and by enzymatic digestion of reduced derivatives, followed by Edman degradation and mass analyses. All of the cycloviolins contain six cysteines, which are present as three intramolecular disulfide bridges. Intriguingly, cycloviolins A-D showed high degrees of sequence homology to the known cyclopsychotride A and circulins A and B from the Rubiaceae family but much less homology to the varv peptides from Viola, a member of the same family (Violaceae).
authors.affiliation: Laboratory of Drug Discovery Research and Development, Developmental Therapeutics Program, Division of Cancer Treatment and Diagnosis, National Cancer Institute, Frederick, Maryland 21702, USA.
authors.forename: Y F
authors.initials: YF
authors.lastname: Hallock
authors.forename: R C
authors.initials: RC
authors.lastname: Sowder
authors.forename: L K
authors.initials: LK
authors.lastname: Pannell
authors.forename: C B
authors.initials: CB
authors.lastname: Hughes
authors.forename: D G
authors.initials: DG
authors.lastname: Johnson
authors.forename: R
authors.initials: R
authors.lastname: Gulakowski
authors.forename: J H
authors.initials: JH
authors.lastname: Cardellina
authors.forename: M R
authors.initials: MR
authors.lastname: Boyd
mesh_terms: D000595:Amino Acid Sequence; D019380:Anti-HIV Agents / Q000737:chemistry* / Q000302:isolation & purification; D002851:Chromatography, High Pressure Liquid; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D010456:Peptides, Cyclic / Q000737:chemistry* / Q000302:isolation & purification; D010944:Plants / Q000737:chemistry*; D017386:Sequence Homology, Amino Acid; D016339:Spectrometry, Mass, Fast Atom Bombardment; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D019380:Anti-HIV Agents; D010456:Peptides, Cyclic