Barite (Ba[SO4]) is one of the promising candidates for sequestration radioactive waste. can incorporate radium (Ra) and form ideal solid solutions, i.e., (Ba,Ra)[SO4]. Together with isostructural celestite (Sr[SO4]), ternary (Ba,Sr,Ra)[SO4], may exist in natural conditions. Our fundamental understanding dissolution kinetics sulfates critically important a better risk assessment nuclear waste r...

Divalent metal ions play a crucial role in catalysis by many RNA and protein enzymes that carry out phosphoryl transfer reactions, and defining their interactions with substrates is critical for understanding the mechanism of biological phosphoryl transfer. Although a vast amount of structural work has identified metal ions bound at the active site of many phosphoryl transfer enzymes, the numbe...

Catalytic aldolase antibodies, generated by reactive immunization, catalyze the aldol reaction with the efficiency of natural enzymes, but accept a much broader range of substrates. Two separate groups of aldolase antibodies that catalyze the same aldol reactions with antipodal selectivity were analyzed by comparing their amino acid sequences with their crystal structures, site-directed mutagen...

The transport of neutral amino acids and their interactions for uptake have been studied in skin-derived-diploid human fibroblasts cultured at confluency. Properly timed preincubations in a medium defined in composition and requirements have been adopted to control size of internal amino acid pools and regulatory interferences affecting amino acid transport. L-Proline, L-alanine, and L-leucine ...

The reactive oxidizing species in the selective oxidation of methane to methanol in oxygen activated Cu-ZSM-5 was recently defined to be a bent mono(μ-oxo)dicopper(II) species, [Cu(2)O](2+). In this communication we report the formation of an O(2)-precursor of this reactive site with an associated absorption band at 29,000 cm(-1). Laser excitation into this absorption feature yields a resonance...

The serine proteinase inhibitor from barley seeds, chymotrypsin inhibitor 2(CI-2), has been crystallized in a molecular complex with subtilisin Novo (EC 3.4.21.14). The crystal structure of this complex has been determined at 2.1-A resolution by the molecular replacement method and partially refined by restrained-parameter least-squares methods. The present crystallographic R factor (SigmaFo[un...