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J. Bacteriol., Jan 1998, 317-329, Vol 180, No. 2
D Bayle, S Wangler, T Weitzenegger, W Steinhilber, J Volz, M Przybylski, KP Schafer, G Sachs and K Melchers
The cop operons of Helicobacter pylori and Helicobacter felis were cloned
by gene library screening. Both operons contain open reading frames for a
P-type ion pump (CopA) with homology to Cd2+ and Cu2+ ATPases and a
putative ion binding protein (CopP), the latter representing a CopZ homolog
of the copYZAB operon of Enterococcus hirae. The predicted CopA ATPases
contained an N-terminal GMXCXXC ion binding motif and a membrane-associated
CPC sequence. A synthetic N- terminal peptide of the H. pylori CopA ATPase
bound to Cu2+ specifically, and gene disruption mutagenesis of CopA
resulted in an enhanced growth sensitivity of H. pylori to Cu2+ but not to
other divalent cations. As determined experimentally, H. pylori CopA
contains four pairs of transmembrane segments (H1 to H8), with the ATP
binding and phosphorylation domains lying between H6 and H7, as found for
another putative transition metal pump of H. pylori (K. Melchers, T.
Weitzenegger, A. Buhmann, W. Steinhilber, G. Sachs, and K. P. Schafer, J.
Biol. Chem. 271:446-457, 1996). The corresponding transmembrane segments of
the H. felis CopA pump were identified by hydrophobicity analysis and via
sequence similarity. To define functional domains, similarly oriented
regions of the two enzymes were examined for sequence identity. Regions
with high degrees of identity included the N- terminal Cu2+ binding domain,
the regions of ATP binding and phosphorylation in the energy transduction
domain, and a transport domain consisting of the last six transmembrane
segments with conserved cysteines in H4, H6, and H7. The data suggest that
H. pylori and H. felis employ conserved mechanisms of ATPase-dependent
copper resistance.
Copyright © 1998, American Society for Microbiology
Properties of the P-type ATPases encoded by the copAP operons of Helicobacter pylori and Helicobacter felis [In Process Citation]
University of California-Los Angeles and Wadsworth Veterans Affairs Medical Center, USA.
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