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Wele, A ; Landon, C ; Labbe, H ; Vovelle, F ; Zhang, YJ ; Bodo, B

Sequence and solution structure of cherimolacyclopeptides A and B, novel cyclooctapeptides from the seeds of Annona cherimola

Tetrahedron 60 (2) 405-414

par Administrateur - publié le

Abstract :

Two new cyclooctapeptides, cherimolacyclopeptide A, cyclo(Pro(1)-Gln(2)-Thr(3)-Gly(4)-Met(5)-Leu(6)-Pro(7)-Ile(8)-) (1) and the related cherimolacyclopeptide B, cyclo(Pro(1)-Gln(2)-Thr(3)-Gly(4)-Mso(5)-Leu(6)-Pro(7)-Ile(8)-) (2), have been isolated from the methanol extract of the seeds of Annona cherimola Miller. The sequences were elucidated on the basis of the MS/MS fragmentation, using a Q-TOF mass spectrometer equipped with an ESI source, chemical degradation and extensive 2D-heteronuclear NMR. The three-dimensional solution structure of cherimolacyclopeptide A (1) determined by H-1 NMR data and molecular modelling is characterised by the presence of two ß turns and a new type of ß-bulge. (C) 2003 Elsevier Ltd. All rights reserved.