1mwz
From Proteopedia
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Solution structure of the N-terminal domain of ZntA in the Zn(II)-form
Overview
Zinc, a metal ion that functions in a wide variety of catalytic and, structural sites in metalloproteins, is shown here to adopt a novel, coordination environment in the Escherichia coli transport protein ZntA., The ZntA protein is a P-type ATPase that pumps zinc out of the cytoplasm, and into the periplasm. It is physiologically selective for Zn(II) and, functions with metalloregulatory proteins in the cell to keep the zinc, quota within strict limits. Yet, the N-terminal cytoplasmic domain, contains a region that is highly homologous to the yeast Cu(I), metallochaperone Atx1. To investigate how the structure of this region may, influence its function, this fragment, containing residues 46-118, has, been cloned out of the gene and overexpressed. We report here the solution, structure of this fragment as determined by NMR. Both the apo and, Zn(II)-ZntA(46-118) structures have been determined. It contains a, previously unknown protein coordination site for zinc that includes two, cysteine residues, Cys59 and Cys62, and a carboxylate residue, Asp58. The, solvent accessibility of this site is also remarkably high, a feature that, increasingly appears to be a characteristic of domains of heavy metal ion, transport proteins. The participation of Asp58 in this ZntA metal ion, binding site may play an important role in modulating the relative, affinities and metal exchange rates for Zn(II)/Pb(II)/Cd(II) as compared, with other P-type ATPases, which are selective for Cu(I) or Ag(I).
About this Structure
1MWZ is a Single protein structure of sequence from Escherichia coli with ZN as ligand. Full crystallographic information is available from OCA.
Reference
A new zinc-protein coordination site in intracellular metal trafficking: solution structure of the Apo and Zn(II) forms of ZntA(46-118)., Banci L, Bertini I, Ciofi-Baffoni S, Finney LA, Outten CE, O'Halloran TV, J Mol Biol. 2002 Nov 8;323(5):883-97. PMID:12417201
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