The plant metallothionein2 from Cicer arietinum (chickpea), cic-MT2, is known to coordinate five divalent metal ions such as Zn(II) or Cd(II), which are arranged in a single metal thiolate cluster. When the Zn(II) form of the protein is titrated with Cd(II) ions in the presence of sulfide ions, an increased Cd(II) binding capacity and concomitant incorporation of sulfide ions into the cluster a...

Calcium ion binding with the anionic part of a molecule was replaced with various metal cations and their inhibitory effects on the replication of herpes simplex virus type 1 were evaluated. Replacement of calcium ion with sodium and potassium ions maintained the antiviral activity while divalent and trivalent metal cations reduced the activity. Depolymerization of sodium spirulan with hydrogen...

Pyrazinamidase of Mycobacterium tuberculosis catalyzes the conversion of pyrazinamide to the active molecule pyrazinoic acid. Reduction of pyrazinamidase activity results in a level of pyrazinamide resistance. Previous studies have suggested that pyrazinamidase has a metal-binding site and that a divalent metal cofactor is required for activity. To determine the effect of divalent metals on the...

Highly charged metal ions act as catalytic centers and structural elements in a broad range of chemical complexes. The nonbonded model for metal ions is extensively used in molecular simulations due to its simple form, computational speed, and transferability. We have proposed and parametrized a 12-6-4 LJ (Lennard-Jones)-type nonbonded model for divalent metal ions in previous work, which showe...

The involvement of metal in oxidation and coupled phosphorylation by cell-free preparations of Mycobacterium phlei was examined. The oxidation of succinate was inhibited by metal-chelating agents, but with /3-hydroxybutyrate, chelating agents exhibited an uncoupling effect. The site of inhibition was found to be between the flavoprotein and the cytochrome b regions of the electron transport cha...

We present a systematic study of the complexation of the new pseudopeptidic ligand isophthaloylbisglycine (H(2)IBG) with divalent metal ions of varying ionic radius. This work represents the initial employment of H(2)IBG in the coordination chemistry of alkaline earth, 3d transition, Zn(II) and Cd(II) metal elements. Infrared, NMR, thermal, magnetic, adsorption and theoretical studies of these ...

The effects of monovalent, divalent, and trivalent cations on the binding of tetrodotoxin and saxitoxin to intact nerves and to a preparation of solubilized nerve membranes have been examined. All eight divalent and trivalent cations tested, and the monovalent ions Li(+), Tl(+), and H(+) appear to compete reversibly with the toxins for their binding site. The ability of lithium to reduce toxin ...

The M-box riboswitch couples intracellular magnesium levels to expression of bacterial metal transport genes. Structural analyses on other riboswitch RNA classes, which typically respond to a small organic metabolite, have revealed that ligand recognition occurs through a combination of base-stacking, electrostatic, and hydrogen-bonding interactions. In contrast, the M-box RNA triggers a change...

To understand the roles of metal ions on the catalytic properties and thermostability of the thermostable beta-galactosidase of Saccharopolyspora rectivirgula, a thermophilic actinomycete, we have investigated the binding kinetics and requirements of divalent metal ions by equilibrium dialysis, titration, and metal ion buffer techniques. We found that the monomeric multimetal enzyme (M(r) 136,9...

Caenorhabditis elegans strains carrying stress-reporter green fluorescent protein transgenes were used to explore patterns of response to metals. Multiple stress pathways were induced at high doses by most metals tested, including members of the heat shock, oxidative stress, metallothionein (mtl) and xenobiotic response gene families. A mathematical model (to be published separately) of the gen...