Unprecedented occurrence of isoaspartic acid in a plant cyclopeptide.
Three structurally related cycloheptapeptides, cyclocitropsides A-C, have been isolated from a MeOH extract of the root bark of Citropsis articulata, a medicinal plant in Uganda. Their sequences were elucidated on the basis of their MS/MS fragmentation, extensive 2D-NMR, chemical degradation, and biochemical modifications. Surprisingly, the sequence of cyclocitropside C differed from that of cyclocitropside B only by an Asp(5)/isoAsp(5) substitution. This is the first report of an isoAsp residue in a plant cyclic peptide.
Molécules de Communication et Adaptation des Micro-Organismes, UMR 7245 CNRS, Muséum National d'Histoire Naturelle, 63 rue Buffon 75005 Paris, France.
Damien
D
Lacroix
Soizic
S
Prado
Dennis
D
Kamoga
John
J
Kasenene
Séverine
S
Zirah
Bernard
B
Bodo
D000595:Amino Acid Sequence; D026581:Isoaspartic Acid / Q000737:chemistry*; D010456:Peptides, Cyclic / Q000737:chemistry* / Q000302:isolation & purification; D018517:Plant Roots / Q000737:chemistry; D010944:Plants / Q000737:chemistry*; D027821:Rutaceae / Q000737:chemistry*
D026581:Isoaspartic Acid; D010456:Peptides, Cyclic