MOLECULAR MODELING OF THE INTERACTION OF CYANOACRYLATE INHIBITORS WITH PHOTOSYSTEM-II .2. THE EFFECT OF STEREOCHEMISTRY OF INHIBITOR BINDING

The 2-cyanoacrylate inhibitors are a potent class of herbicides which block electron transfer in photosystem II. The spatial arrangement of different functional groups are an important factor in determining act ivity and a number of derivatives have been used as stereospecific pro bes of the secondary quinone binding site. More than one region of ste reoselectivity in the binding site has been identified which influence s the interaction with specific groups of the inhibitor. We have studi ed the interaction of various stereoisomers of the cyanoacrylates with the binding site in the D 1 protein (residues Leu 210 to Val 280) by determining the nonbonded intermolecular energies between the modelled structures calculated by van der Waals and electrostatic interactions after energy minimization of the combined structures to reduce inter and intramolecular strain and have found that the results reflect the experimentally determined data.