Linked Life Data

12145281

Source:http://linkedlifedata.com/resource/pubmed/id/12145281

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
40
pubmed:dateCreated
2002-9-30
pubmed:databankReference
pubmed:abstractText
Methionine residues in proteins are susceptible to oxidation, and the resulting methionine sulfoxides can be reduced back to methionines by methionine-S-sulfoxide reductase (MsrA) and methionine-R-sulfoxide reductase (MsrB). Herein, we have identified two MsrB families that differ by the presence of zinc. Evolutionary analyses suggested that the zinc-containing MsrB proteins are prototype enzymes and that the metal was lost in certain MsrB proteins later in evolution. Zinc-containing Drosophila MsrB was further characterized. The enzyme was found to employ a catalytic Cys(124) thiolate, which directly interacted with methionine sulfoxide, resulting in methionine and a Cys(124) sulfenic acid intermediate. A subsequent reaction of this intermediate with Cys(69) generated an intramolecular disulfide. Dithiothreitol could reduce either the sulfenic acid or the disulfide, but the disulfide was a preferred substrate for thioredoxin, a natural electron donor. Interestingly, the C69S mutant could complement MsrA/MsrB deficiency in yeast, and the corresponding natural form of mouse MsrB was active with thioredoxin. These data indicate that MsrB proteins employ alternative mechanisms for sulfenic acid reduction. Four other conserved cysteines in Drosophila MsrB (Cys(51), Cys(54), Cys(101), and Cys(104)) were found to coordinate structural zinc. Mutation of any one or a combination of these residues resulted in complete loss of metal and catalytic activity, demonstrating an essential role of zinc in Drosophila MsrB. In contrast, two conserved histidines were important for thioredoxin-dependent activity, but were not involved in zinc binding. A Drosophila MsrA gene was also cloned, and the recombinant enzyme was found to be metal-free and specific for methionine S-sulfoxide and to employ a similar sulfenic acid/disulfide mechanism.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
4
pubmed:volume
277
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
37527-35
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed-meshheading:12145281-Amino Acid Sequence, pubmed-meshheading:12145281-Animals, pubmed-meshheading:12145281-Base Sequence, pubmed-meshheading:12145281-Cattle, pubmed-meshheading:12145281-DNA Primers, pubmed-meshheading:12145281-Drosophila, pubmed-meshheading:12145281-Drosophila melanogaster, pubmed-meshheading:12145281-Evolution, Molecular, pubmed-meshheading:12145281-Humans, pubmed-meshheading:12145281-Kinetics, pubmed-meshheading:12145281-Methionine Sulfoxide Reductases, pubmed-meshheading:12145281-Molecular Sequence Data, pubmed-meshheading:12145281-Mutagenesis, Site-Directed, pubmed-meshheading:12145281-Oxidoreductases, pubmed-meshheading:12145281-Recombinant Proteins, pubmed-meshheading:12145281-Sequence Alignment, pubmed-meshheading:12145281-Sequence Homology, Amino Acid, pubmed-meshheading:12145281-Zinc
pubmed:year
2002
pubmed:articleTitle
Reaction mechanism, evolutionary analysis, and role of zinc in Drosophila methionine-R-sulfoxide reductase.
pubmed:affiliation
Department of Biochemistry, University of Nebraska, Lincoln, Nebraska 68588, USA.
pubmed:publicationType
Journal Article, Comparative Study