Linked Life Data

12682056

Source:http://linkedlifedata.com/resource/pubmed/id/12682056

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
27
pubmed:dateCreated
2003-6-30
pubmed:abstractText
Arsenate reductase (ArsC) from Staphylococcus aureus plasmid pI258 catalyzes the reduction of arsenate to arsenite and plays a role in bacterial heavy metal resistance. The high resolution x-ray structure of ArsC reveals the atomic details of the K+ binding site situated next to the catalytic P-loop structural motif of this redox enzyme. A full thermodynamic study of the binding characteristics of a series of monovalent cations (Li+, Na+, K+, Rb+, and Cs+) and their influence on the thermal stability of ArsC was performed with isothermal titration calorimetry, circular dichroism spectroscopy, and differential scanning calorimetry. Potassium has the largest affinity with a Ka of 3.8 x 10(3) m(-1), and the effectiveness of stabilization of ArsC by monovalent cations follows the binding affinity order: K+ > Rb+ > Cs+ > Na+ > Li+. A mutagenesis study on the K+ binding side chains showed that Asn-13 and Asp-65 are essential for potassium binding, but the impact on the stability of ArsC was the most extreme when mutating Ser-36. Additionally, the thermal stabilization by K+ is significantly reduced in the case of the ArsC E21A mutant, showing the importance of a Glu-21-coordinated water molecule in its contact with K+. Although potassium is not essential for catalysis, in its presence the kcat/KM increases with a factor of 5. Altogether, the interaction of K+ with specific residues in ArsC is an enthalpydriven process that stabilizes ArsC and increases the specific activity of this redox enzyme.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
4
pubmed:volume
278
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
24673-9
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
Specific potassium binding stabilizes pI258 arsenate reductase from Staphylococcus aureus.
pubmed:affiliation
Department Ultrastructure, Vlaams interuniversitair Instituut voor Biotechnologie, Vrije Universiteit Brussel, Pleinlaan 2, Belgium. nina.lah@uni-lj.si
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't