Structural characterization of toxic cyclic peptides from blue-green algae by tandem mass spectrometry

摘要: Abstract Combined use of chemical degradation, derivatization, and tandem mass spectrometry for rapid structural characterization toxic cyclic peptides from blue-green algae at the nanomole level is described. Previously, all algal toxins were thought to belong a family seven-residue peptides, having general structure cyclo-D-Ala-L-Xaa-erythro-beta-methyl-D-isoaspartic acid-L-Yaa-Adda-D-isoglutamic acid-N-methyldehydroalanine, where Xaa Yaa represent variable amino acids L configuration Adda 3-amino-9-methoxy-2,6,8-trimethyl-10-phenyl-deca-4,6-dienoic acid. Structural two additional indicates that further variability can exist within this naturally occurring peptides. Isoaspartic acid dehydroalanine substitute beta-methylisoaspartic N-methyldehydroalanine, respectively.