Metalloregulatory protein

It has been demonstrated that extremely tight control is exhibited over the intracellular zinc concentrations by the metalloregulatory proteins controlling zinc homeostasis. It had previously been thought that intracellular zinc was available in a pool of free zinc ions in the micro- to pico-molar concentration. An important study shows that these concentrations of free zinc are inconsistent with the concentrations required to trigger zinc uptake.974... 

Outten CE, O Halloran TV (2001) Femtomolar sensitivity of metalloregulatory proteins controlling zinc homeostasis. Science 292 2488-2492... 

The synthesis, structures, and reactivities of metal thiolates with group 4 and 5 metals, and the synthesis and study of copper-thiolates have been reviewed. Hg thiolate chemistry has been reviewed and related to the binding of Hg in vivo by metalloregulatory proteins. A range of two-, three-, and four-coordinate Hg thiolate complexes has been prepared, and comparisons with the metalloregulatory protein, Hg-MerR,... 

The metalloregulatory protein arsR was overexpressed in Escherichia coli and resulted in both elevated levels of arsenite bioaccumulation leading to severe reduction in cellular growth (Kostal et al, 2004), and the efficacy of this strain at low arsenic levels. Equivalent strains overexpressing PC synthase genes and arsR could be developed to have arsenic hypertolerant strains with higher bioaccumulation, valuable for the bioremediation of arsenic. 

Metal Transport Through Membranes Chemistry of Metallochaperones Chemistry of Metalloenzymes Metalloregulatory Proteins... 

One of the first metalloregulatory proteins to be characterized extensively is the prokaryotic MerR transcription factor (1, 6, 7), which acts either as a repressor (apo-protein) or an activator (holo-protein) of the mer operon encoding mercury resistance proteins (Fig. Ic). The —35 and —10 sequence elements of the mer promoter, binding sites for the RNA polymerase initiation complex, are separated by an unusually long distance that results in poor constitutive transcription. Apo-MerR binds to the DNA between these sequences and bends the DNA, which results in a slight increase in repression on the suboptimal promoter. It also recruits the RNA polymerase to the transcription start site where it waits in a stalled complex. Upon binding of... 

An intriguing problem about which we know very little is the mechanism of metal identification by the body that triggers Its response, as in the case of the huild-up of metallothioneins upon exposure to toxic metals. Perhaps the best understood of the metalloregulatory proteins is MerR that protects bacteria from mercurial toxicity. It is extremely sensitive to Hg, and distinguishes it from its congeners Zn and Cd. There is good evidence that the mercury receptor forms three-coordinate mercury(II) complexes (see Fig. 12.1c), making possible this specificity. ... 

Bittel, D.C., I.V. Smirnova and G.K. Andrews. Functional heterogeneity in the zinc fingers of metalloregulatory protein metal response element-binding transcription factor-1. J. Biol. Chem. 275 37194-37201, 2000. 

S-oxidizing bacteria), many are probably most appropriate for ex situ use in bioreactors, where the mobilized or immobilized metal can be separated from soil components (White et al., 1998). Living or dead fungal and bacterial biomass and metabolites have been used to remove metals, radionuclides, and metalloids from solution by biosorption or chelation (Macaskie, 1991 Gadd, 2001). The metalloregulatory protein MerR, which exhibits high affinity and selectivity toward mercury, was exploited for the construction of microbial biosorbents specific for mercury removal (Bae et ah, 2001, 2002, 2003). Whole-cell sorbents... 

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