scholarly journals The metal-binding sites of the zinc-transporting P-type ATPase of Escherichia coli. Lys693 and Asp714 in the seventh and eighth transmembrane segments of ZntA contribute to the coupling of metal binding and ATPase activity

2006 ◽  
Vol 1757 (11) ◽  
pp. 1485-1495 ◽  
Author(s):  
Juha Okkeri ◽  
Tuomas Haltia
Keyword(s):  
Escherichia Coli ◽  
Atpase Activity ◽  
Metal Binding ◽  
Binding Sites ◽  
Transmembrane Segments ◽  
Metal Binding Sites ◽  
P Type

scholarly journals Investigation of the nature of the two metal-binding sites in 5-aminolaevulinic acid dehydratase from Escherichia coli

1994 ◽  
Vol 300 (2) ◽  
pp. 373-381 ◽  
Author(s):  
P Spencer ◽  
P M Jordan
Keyword(s):  
Escherichia Coli ◽  
Metal Ions ◽  
Metal Binding ◽  
Binding Sites ◽  
Metal Ion ◽  
Protein Fluorescence ◽  
Metal Binding Sites ◽  
Aminolaevulinic Acid ◽  
Acid Dehydratase ◽  
Aminolaevulinic Acid Dehydratase

Two distinct metal-binding sites, termed alpha and beta, have been characterized in 5-aminolaevulinic acid dehydratase from Escherichia coli. The alpha-site binds a Zn2+ ion that is essential for catalytic activity. This site can also utilize other metal ions able to function as a Lewis acid in the reaction mechanism, such as Mg2+ or Co2+. The beta-site is exclusively a transition-metal-ion-binding site thought to be involved in protein conformation, although a metal bound at this site only appears to be essential for activity if Mg2+ is to be bound at the alpha-site. The alpha- and beta-sites may be distinguished from one another by their different abilities to bind divalent-metal ions at different pH values. The occupancy of the beta-site with Zn2+ results in a decrease of protein fluorescence at pH 6. Occupancy of the alpha- and beta-sites with Co2+ results in u.v.-visible spectral changes. Spectroscopic studies with Co2+ have tentatively identified three cysteine residues at the beta-site and one at the alpha-site. Reaction with N-ethyl[14C]maleimide preferentially labels cysteine-130 at the alpha-site when Co2+ occupies the beta-site.

scholarly journals Escherichia coli inorganic pyrophosphatase : site-directed mutagenesis of the metal binding sites

FEBS Letters ◽  
1996 ◽  
Vol 399 (1-2) ◽  
pp. 99-102 ◽  
Author(s):  
Svetlana Avaeva ◽  
Pavel Ignatov ◽  
Svetlana Kurilova ◽  
Tatjana Nazarova ◽  
Elena Rodina ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Metal Binding ◽  
Binding Sites ◽  
Site Directed Mutagenesis ◽  
Inorganic Pyrophosphatase ◽  
Directed Mutagenesis ◽  
Metal Binding Sites

Periplasmic domain of CusA in an Escherichia coli Cu+/Ag+ transporter has metal binding sites

2010 ◽  
Vol 48 (6) ◽  
pp. 829-835 ◽  
Author(s):  
Bo-Young Yun ◽  
Yongbin Xu ◽  
Shunfu Piao ◽  
Nahee Kim ◽  
Jeong-Hyun Yoon ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Metal Binding ◽  
Binding Sites ◽  
Metal Binding Sites ◽  
Periplasmic Domain

scholarly journals Copper binding to the N-terminal metal-binding sites or the CPC motif is not essential for copper-induced trafficking of the human Wilson protein (ATP7B)

2006 ◽  
Vol 401 (1) ◽  
pp. 143-153 ◽  
Author(s):  
Michael A. Cater ◽  
Sharon La fontaine ◽  
Julian F. B. Mercer
Keyword(s):  
Metal Binding ◽  
Binding Sites ◽  
Site Directed Mutagenesis ◽  
Copper Binding ◽  
Phosphatase Domain ◽  
Copper Chelation ◽  
Metal Binding Sites ◽  
Excess Copper ◽  
Wilson Protein ◽  
P Type

The Wilson protein (ATP7B) is a copper-translocating P-type ATPase that mediates the excretion of excess copper from hep-atocytes into bile. Excess copper causes the protein to traffic from the TGN (trans-Golgi network) to subapical vesicles. Using site-directed mutagenesis, mutations known or predicted to abrogate catalytic activity (copper translocation) were introduced into ATP7B and the effect of these mutations on the intracellular traf-ficking of the protein was investigated. Mutation of the critical aspartic acid residue in the phosphorylation domain (DKTGTIT) blocked copper-induced redistribution of ATP7B from the TGN, whereas mutation of the phosphatase domain [TGE (Thr-Gly-Glu)] trapped ATP7B at cytosolic vesicular compartments. Our findings demonstrate that ATP7B trafficking is regulated with its copper-translocation cycle, with cytosolic vesicular localization associated with the acyl-phosphate intermediate. In addition, mut-ation of the six N-terminal metal-binding sites and/or the trans-membrane CPC (Cys-Pro-Cys) motif did not suppress the consti-tutive vesicular localization of the ATP7B phosphatase domain mutant. These results suggested that copper co-ordination by these sites is not essential for trafficking. Importantly, copper-chelation studies with these mutants clearly demonstrated a requirement for copper in ATP7B trafficking, suggesting the presence of an additional copper-binding site(s) within the protein. The results presented in this report significantly advance our understanding of the regulatory mechanism that links copper-translocation activity with copper-induced intracellular trafficking of ATP7B, which is central to hepatic and hence systemic copper homoeostasis.

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