Hydrophilic Photosystem II Inhibitors: Cyanoacrylate Thiolate Salts

Cyanoacrylate thiolate salts such as the sodium salt o f ethoxyethyl-3-/?-chlorobenzylthio2-cyano-3-m ercapto acrylate have been shown to be relatively slow binding, po ten t inhibitors o f photosynthetic electron transport, th a t are equally active against thylakoids isolated from atrazine-susceptible and atrazine-resistant Brassica napus seedlings. It has been suggested tha t their m ode o f binding involves the substituted benzyl g roup interacting w ith the m em brane lipids and the thiolate ion interacting in the region o f the histidine215 residue o f the D, peptide, close to the non-hem e Fe centre. This, together with their slow rate o f binding, has led to the thiolate salts being classified as phenol type inhibitors.