The activity of ribonuclease increases with increasing concentration of added divalent metal ions until the attainment of an optimal metal concentration, beyond which the addition of further metal ions inhibits the reaction. When either the optimal metal concentration or the enzymatic activity at that concentration is plotted versus the atomic number of the transition metals, the resulting curv...

Alkaline phosphatase (EC 3.1.3.1) from bovine intestinal mucosa (BIAP) is an homodimeric metalloenzyme, containing one Mg2+ and two Zn2+ ions in each active site. ApoBIAP, prepared using ion-chelating agents, exhibited a dramatic decrease of its hydrolase activity, concomittant to conformational changes in its quaternary structure. By rate-zonal centrifugation and electrophoresis, we demonstrat...

A novel SmtB/ArsR family metalloregulator, denoted BxmR, has been identified and characterized from the cyanobacterium Oscillatoria brevis. Genetic and biochemical evidence reveals that BxmR represses the expression of both bxa1, encoding a CPx-ATPase metal transporter, as well as a divergently transcribed operon encoding bxmR and bmtA, a heavy metal sequestering metallothionein. Derepression o...

We functionalized peptide nanofibers to provide a nano-scale template for the display of biomolecules and inorganic nanoparticles using metal ion coordination. Nanofibers assembled only in the presence of certain divalent metal ions, and could be readily dissolved by a metal-chelating reagent, EDTA.

The adsorption curves of divalent metal ions (M2+) to an iminodiacetate(IDA)-type chelating resin (-L2-) under the condition of metal ions in excess against IDA groups clearly indicated the difference in contribution between two species. Copper and nickel are adsorbed only as [(-L)M(II)], while cadmium and calcium are adsorbed as [(-L)M(II)] and [(-LH)2M(II)]. Addition of salts may enhance the ...

A technique for preparing heterobimetallic frameworks with tunable metal sites is demonstrated by the synthesis of a new two-dimensional metal-organic framework that is constructed from tetra(4-carboxyphenyl)porphyrin and Cd(II) species. The solid can be prepared in the presence of other divalent transition metals to yield the same framework with the smaller metal ions occupying the porphyrin l...

In connection with studies on the /3-keto acid carboxylases of plants (1, 2), the effects of metal ions on the decarboxylation of oxalacetic acid, in the presence and absence of enzyme, were studied. In confirmation of Krebs (3) the decarboxylation was found to be accelerated by a variety of polyvalent cations. It was also observed that the enzyme oxalacetic carboxylase from parsley roots, whic...

We report a detailed comparison between calculations of inter-filament interactions based on Monte-Carlo simulations and experimental features of lateral aggregation of bacteriophages fd and M13 induced by a number of divalent metal ions. The general findings are consistent with the polyelectrolyte nature of the virus filaments and confirm that the solution electrostatics account for most of th...

Significant cleavage by hammerhead ribozymes requires activation by divalent metal ions. Several models have been proposed to account for the influence of metal ions on hammerhead activity. A number of recent papers have presented data that have been interpreted as supporting a one-metal-hydroxide-ion mechanism. In addition, a solvent deuterium isotope effect has been taken as evidence against ...

RNase H1 from Halobacterium sp. NRC-1 (Halo-RNase H1) is characterized by the abundance of acidic residues on the surface, including bi/quad-aspartate site residues. Halo-RNase H1 exists in partially folded (I) and native (N) states in low-salt and high-salt conditions respectively. Its folding is also induced by divalent metal ions. To understand this unique folding mechanism of Halo-RNase H1,...