Fig. 3

Chemical structures of cyanopeptides of the classes anabaenopeptins, cyanopeptolins, cyclamides, microcystins, and aeruginosins. The characteristic core structure of each cyanopeptide class is highlighted in black, while the variable building blocks of the molecule are depicted in gray. Main peptides produced by the four cyanobacterial strains (> 1% to total abundance) are listed with their amino acid building block strings in addition to the represented structure above. The photochemically reactive moieties of tyrosine and methionine are highlighted in red and blue, respectively. The light absorbance range and the second-order reaction rate constants with hydroxyl radical and singlet oxygen for tyrosine and methionine are listed