Linked Life Data

20333422

Source:http://linkedlifedata.com/resource/pubmed/id/20333422

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
2010-5-27
pubmed:abstractText
Nickel-dependent superoxide dismutase (NiSOD) is a member of a class of metalloenzymes that protect aerobic organisms from the damaging superoxide radical (O(2) (.-)). A distinctive and fascinating feature of NiSOD is the presence of active-site nickel-thiolate interactions involving the Cys2 and Cys6 residues. Mutation of one or both Cys residues to Ser prevents catalysis of O(2) (.-), demonstrating that both residues are necessary to support proper enzymatic activity (Ryan et al., J Biol Inorg Chem, 2010). In this study, we have employed a combined spectroscopic and computational approach to characterize three Cys-to-Ser (Cys --> Ser) mutants (C2S, C6S, and C2S/C6S NiSOD). Similar electronic absorption and magnetic circular dichroism spectra are observed for these mutants, indicating that they possess nearly identical active-site geometric and electronic structures. These spectroscopic data also reveal that the Ni(2+) ion in each mutant adopts a high-spin (S = 1) configuration, characteristic of a five- or six-coordinate ligand environment, as opposed to the low-spin (S = 0) configuration observed for the four-coordinate Ni(2+) center in the native enzyme. An analysis of the electronic absorption and magnetic circular dichroism data within the framework of density functional theory computations performed on a series of five- and six-coordinate C2S/C6S NiSOD models reveals that the active site of each Cys --> Ser mutant possesses an essentially six-coordinate Ni(2+) center with a rather weak axial bonding interaction. Factors contributing to the lack of catalytic activity displayed by the Cys --> Ser NiSOD mutants are explored.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
1432-1327
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
15
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
777-93
pubmed:dateRevised
2011-9-26
pubmed:meshHeading
pubmed:year
2010
pubmed:articleTitle
Spectroscopic and computational investigation of three Cys-to-Ser mutants of nickel superoxide dismutase: insight into the roles played by the Cys2 and Cys6 active-site residues.
pubmed:affiliation
Department of Chemistry, University of Wisconsin-Madison, 53706, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, N.I.H., Extramural