RNase H1 from extreme halophilic archaeon Halobacterium sp. NRC-1 (Halo-RNH1) consists of an N-terminal domain with unknown function and a C-terminal RNase H domain. It is characterized by the high content of acidic residues on the protein surface. The far- and near-UV CD spectra of Halo-RNH1 suggested that Halo-RNH1 assumes a partially folded structure in the absence of salt and divalent metal...

Combinations of chemical and genetic approaches were used to study the function of divalent metal ions in cleavage of RNA by the ribozyme RNase P RNA. We show that different divalent metal ions have differential effects on cleavage site recognition and rescue of cleavage activity by mixing divalent metal ions that do not promote cleavage by themselves. We conclude that efficient and correct cle...

The hammerhead ribozyme is generally accepted as a well characterized metalloenzyme. However, the precise nature of the interactions of the RNA with metal ions remains to be fully defined. Examination of metal ion-catalyzed hammerhead reactions at limited concentrations of metal ions is useful for evaluation of the role of metal ions, as demonstrated in this study. At concentrations of Mn2+ ion...

Lead(II)-induced cleavage can be used as a tool to probe conformational changes in RNA. In this report, we have investigated the conformation of M1 RNA, the catalytic subunit of Escherichia coli RNase P, by studying the lead(II)-induced cleavage pattern in the presence of various divalent metal ions. Our data suggest that the overall conformation of M1 RNA is very similar in the presence of Mg(...

BACKGROUND The catalytic activity of RNA enzymes is thought to require divalent metal ions, which are believed to facilitate RNA folding and to play a direct chemical role in the reaction. RESULTS We have found that the hammerhead, hairpin and VS ribozymes do not require divalent metal ions, their mimics such as [Co(NH3)6]3+, or even monovalent metal ions for efficient self-cleavage. The HDV ...

BACKGROUND The pathological hallmark of Parkinson's disease is the deposition of cytoplasmic neuronal inclusions termed Lewy bodies. The major component of Lewy bodies is amyloid fibrils of α-synuclein. To investigate what causes α-synuclein aggregation is essential to understand its pathological roles in Parkinson's disease. Various metal ions, including iron and copper, have been implicated i...

Biosorption of monovalent ions Na+ and K+, by deactivated protonated yeast (Saccharomyces cerevisiae) at controlled pH, was compared with biosorption of divalent ions Ca2+ and Mg2+ to help to understand the underlying bindingmechanisms. The adsorption for monovalent ions was accompanied by H+ release. Divalent ions were sorbed by proton displacement, and also an additional mode not accompanied ...

The structure and activity of nucleic acids depend on their interactions with metal ions. Fundamental to these interactions is the degree of specificity observed between the metal ions and nucleic acids, and a complete description of nucleic acid folding requires that we understand the nature of the interactions with metal ions, including specificity. The prior demonstration that high concentra...

The relative permeability of endplate channels to monovalent and divalent metal ions was determined from reversal potentials. Thallium is the most permeant ion with a permeability ratio relative to Na+ of 2.5. The selectivity among alkali metals is weak with a sequence, Cs+ greater than Rb+ greater than K+ greater than Na+ greater than Li+, and permeability ratios of 1.4, 1.3, 1.1, 1.0, and 0.9...

A pseudo-second order rate equation describing the kinetics of sorption of divalent metal ions on to sphagnum moss peat at various initial metal ion concentrations and peat doses has been developed. The sorption kinetics were followed based on the concentrations of metal sorbed at various time intervals. Results show that chemical sorption processes might be rate-limiting for the sorption of di...