An investigation into the specificity of soman analogues toward the antibody BE2 using electrostatic potentials

We examine 19-pinacolyl (methyl) phosphonofluoridate (soman) [CH3P(O)(F)OCH(CH3)-C(CH3)3] analogues and correlate their fine specificity toward the antibody BE2 using electrostatic potentials (EP) based on INDO/S calculations. It is found that the shape of electrostatic potential surfaces can be used to anticipiate the relative binding within this homologous series of molecules. Molecules with an isolated ellipsoidal-negative region representing the PO bond have poor relative inhibition, whereas elongated negative regions typically enclosing O-P-O or F-P-O regions, which are also surrounded by positive regions, are the most active. We present three-dimensional color-coded EPs to demonstrate these points.