TY - JOUR
T1 - A new zinc-protein coordination site in intracellular metal trafficking
T2 - Solution structure of the Apo and Zn(II) forms of ZntA(46-118)
AU - Banci, Lucia
AU - Bertini, Ivano
AU - Ciofi-Baffoni, Simone
AU - Finney, Lydia A.
AU - Outten, Caryn E.
AU - O'Halloran, Thomas V.
N1 - Funding Information:
This work was supported by the European Community (contract HPRI-CT-1999-00009), by the Italian CNR (Progetto Finalizzato Biotecnologie 01.00238.PF49) and by MURST-ex 40%; by NIH grants RO1 GM 54111 and R01 GM38784 (to T.V.O.), and Biophysics training grant T32 GM08382 (to C.E.O.). L.A.F. acknowledges support as a Fellow of the Fannie and John Hertz Foundation.
PY - 2002
Y1 - 2002
N2 - 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).
AB - 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).
KW - NMR structure
KW - Novel zinc coordination environment
KW - P-type ATPase
KW - Zinc transporting protein
KW - ZntA
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U2 - 10.1016/S0022-2836(02)01007-0
DO - 10.1016/S0022-2836(02)01007-0
M3 - Article
C2 - 12417201
AN - SCOPUS:0036431502
SN - 0022-2836
VL - 323
SP - 883
EP - 897
JO - Journal of Molecular Biology
JF - Journal of Molecular Biology
IS - 5
ER -