Metal ions are indispensable for maintaining the structural stability and catalytic activity of metalloproteins. Molecular modeling studies of such proteins with force fields, however, are often hampered by the “missing parameter” problem. In this study, we have derived bond-stretching and angle-bending parameters applicable to zinc-containing systems which are compatible with the AMBER force field. A total of 18 model systems were used to mimic the common coordination configurations observed in the complexes formed by zinc-containing metalloproteins. The Hessian matrix of each model system computed at the B3LYP/6-311++G(2d,2p) level was then analyzed by Seminario’s method to derive the desired force constants. These parameters were validated extensively in structural optimizations and molecular dynamics simulations of four selected model systems as well as one protein−ligand complex formed by carbonic anhydrase II. The best performance was achieved by a bonded model in combination with the atomic partial...
The two enantiomers of 2-(2-hydroxybiphenyl-4-yl)propanoic acid ((S)- and (R)-BPOH) have been selected as probes for human serum albumin (HSA). Photophysical characterization in the absence of protein led to emission maxima, singlet energies, quantum yields, and fluorescence lifetime values ... more
The photodissociation of H2O in its B band is a prototype for nonadiabatic reaction dynamics. In addition to dissociation via the adiabatic pathway to the OH(Ã2Σ+) + H fragments, it also produces the OH(X̃2Π) + H fragments through two nonadiabatic pathways: the B̃ → X̃ transition via two co ... more
Due to the widespread occurrence in the environment and potential risk toward organisms of fluoroquinolones (FQs), it is of importance to develop high efficient methods for assessing their occurrence and environmental risk. A monoclonal antibody (Mab) with broad cross-reactivity to FQs was ... more
Rohm and Haas Powder Coatings is delighted to announce that its Reading, Pennsylvania, facility is the first site in the world to receive the RCMS® Site Certification awarded by the American Chemical Council (ACC).
When Raj Gupta, Chairman and CEO of Rohm and Haas Company, became Chairman ... more