Walter J. Stevens

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The activation of the thiol of glutathione (GSH) bound in the active site of the class mu glutathione transferase M1-1 from rat involves a hydrogen-bonding network that includes a direct (first-sphere) interaction between the hydroxyl group of Y6 and the sulfur of GSH and second-sphere interactions involving a hydrogen bond between the main-chain amide N-H(More)
Clinical and biologic features of adult Still's disease developed in a patient who had high antibody titers against Yersinia enterocolitica during his illness. Immunocomplexes containing antibodies against Yersinia antigens were isolated at the beginning of the disease. Yersinia was not isolated from blood or stool specimens probably because we observed the(More)
An effective fragment model is developed to treat solvent effects on chemical properties andreactions. The solvent, which might consist of discrete water molecules, protein, or othermaterial, is treated explicitly using a model potential that incorporates electrostatics,polarization, and exchange repulsion effects. The solute, which one can most generally(More)
The effective fragment potential (EFP) method is described and its capabilities illustrated using several applications. The original method, EFP1, was primarily developed to describe aqueous solvation, by representing Coulombic, induction and repulsive interactions via one-electron terms in the ab initio Hamiltonian. It is demonstrated, using water(More)
A formula to calculate the charge penetration energy that results when two charge densities overlap has been derived for molecules described by an effective fragment potential (EFP). The method has been compared with the ab initio charge penetration, taken to be the difference between the electrostatic energy from a Morokuma analysis and Stone’s Distributed(More)
The reaction of hemoglobin (Hb) with dinitrobenzenes (DNBs) was studied to develop a molecular-level understanding of such reactions that will enhance the development of toxicokinetic models that employ Hb adducts as biomarkers for exposure. Methemoglobin (metHb) is formed during the reaction and UV/VIS spectroscopy was used to follow the reaction of DNB(More)
The binding of cis-Pt(NH3)2B1B2 to the bases B1 and B2, i.e., guanine (G), cytosine (C), adenine (A), and thymine (T), of DNA is studied theoretically. The components of the binding are analyzed and a model structure is proposed for the intrastrand binding to the dB1pdB2 sequence of a kinked double helical DNA. Quantum mechanical calculations of the ligand(More)
Ab initio calculations have been carried out for the potential energy curves and transition moments of the ' 2 2 , '&, 2H,, and '2; states of Ar$ which arise from the z P + ' S ion-atom asymptote. These data have been used in a theoretical calculation of the dissociative absorption cross sections from the bound '2; state to the repulsive '11, and '2:(More)