Voltammetric Study of Some 3-Aryl-quinoxaline-2-carbonitrile 1,4-di-N-oxide Derivatives with Anti-Tumor Activities.

The electrochemical properties of twenty 3-aryl-quinoxaline-2-carbonitrile 1,4-di--oxide derivatives with varying degrees of cytotoxic activity were investigated in dimethylformamide (DMF) using cyclic voltammetry and first derivative cyclic voltammetry. With one exception, the first reduction of these compounds was found to be reversible or quasireversible and is attributed to reduction of the -oxide moiety to form a radical anion. The second reduction of the diazine ring was found to be irreversible.

MoD-QM/MM Structural Refinement Method: Characterization of Hydrogen Bonding in the Oxytricha nova G-Quadruplex.

A generalization of the Moving-Domain Quantum Mechanics/Molecular Mechanics (MoD-QM/MM) hybrid method [Gascon, J. A.; Leung, S.

Role of electrostatics in differential binding of RalGDS to Rap mutations E30D and K31E investigated by vibrational spectroscopy of thiocyanate probes.

The human protein Rap1A (Rap) is a member of the Ras superfamily of GTPases that binds to the downstream effector Ral guanine nucleotide dissociation stimulator (RalGDS). Although Ras and Rap have nearly identical amino acid sequences and structures along the effector binding surface, the charge reversal mutation Rap K31E has previously been shown to increase the dissociation constant of Rap-RalGDS docking to values similar to that of Ras-RalGDS docking. This indicates that the difference in charge at position 31 could provide a mechanism for Ral to distinguish two structurally similar but functionally distinct GTPases, which would be of vital importance for appropriate biological function.