Cellular zinc status alters chromatin accessibility and binding of p53 to DNA.

Zn is an essential metal required by approximately 850 human transcription factors. How these proteins acquire their essential Zn cofactor and whether they are sensitive to changes in the labile Zn pool in cells remain open questions. Using ATAC-seq to profile regions of accessible chromatin coupled with transcription factor enrichment analysis, we examined how increases and decreases in the labile zinc pool affect chromatin accessibility and transcription factor enrichment.

Identification, Characterization, and Electronic Structures of Interconvertible Cobalt-Oxygen TAML Intermediates.

The reaction of Li[(TAML)Co]·3HO (TAML = tetraamido macrocyclic tetraanionic ligand) with iodosylbenzene at 253 K in acetone in the presence of redox-innocent metal ions (Sc(OTf) and Y(OTf)) or triflic acid affords a blue species , which is converted reversibly to a green species upon cooling to 193 K. The electronic structures of and have been determined by combining advanced spectroscopic techniques (X-band electron paramagnetic resonance (EPR), electron nuclear double resonance (ENDOR), X-ray absorption spectroscopy/extended X-ray absorption fine structure (XAS/EXAFS), and magnetic circular dichroism (MCD)) with theoretical studies. Complex is best represented as an = 1/2 [(Sol)(TAML)Co---OH(LA)] species (LA = Lewis/Brønsted acid and Sol = solvent), where an = 1 Co(III) center is antiferromagnetically coupled to = 1/2 TAML, which represents a one-electron oxidized TAML ligand.

Cellular zinc status alters chromatin accessibility and binding of transcription factor p53 to genomic sites.

Zinc (Zn) is an essential metal required by approximately 2500 proteins. Nearly half of these proteins act on DNA, including > 850 human transcription factors, polymerases, DNA damage response factors, and proteins involved in chromatin architecture. How these proteins acquire their essential Zn cofactor and whether they are sensitive to changes in the labile Zn pool in cells remain open questions.

Zinc sequestration by human calprotectin facilitates manganese binding to the bacterial solute-binding proteins PsaA and MntC.

Zinc is an essential transition metal nutrient for bacterial survival and growth but may become toxic when present at elevated levels. The Gram-positive bacterial pathogen Streptococcus pneumoniae is sensitive to zinc poisoning, which results in growth inhibition and lower resistance to oxidative stress. Streptococcus pneumoniae has a relatively high manganese requirement, and zinc toxicity in this pathogen has been attributed to the coordination of Zn(II) at the Mn(II) site of the solute-binding protein (SBP) PsaA, which prevents Mn(II) uptake by the PsaABC transport system.

pH Dependent Reversible Formation of a Binuclear Ni Metal-Center Within a Peptide Scaffold.

A disulfide-bridged peptide containing two Ni binding sites based on the nickel superoxide dismutase protein, {Ni(SOD)}, has been prepared. At physiological pH (7.4) it was found that the metal sites are mononuclear with a square planar NOS coordination environment with the two sulfur-based ligands derived from cysteinate residues, the nitrogen ligand derived from the amide backbone and a water ligand.