RRC ID 72028
Author Vieira Dos Santos C, Cuiné S, Rouhier N, Rey P.
Title The Arabidopsis plastidic methionine sulfoxide reductase B proteins. Sequence and activity characteristics, comparison of the expression with plastidic methionine sulfoxide reductase A, and induction by photooxidative stress.
Journal Plant Physiol
Abstract Two types of methionine (Met) sulfoxide reductases (Msr) catalyze the reduction of Met sulfoxide (MetSO) back to Met. MsrA, well characterized in plants, exhibits an activity restricted to the Met-S-SO-enantiomer. Recently, a new type of Msr enzyme, called MsrB, has been identified in various organisms and shown to catalytically reduce the R-enantiomer of MetSO. In plants, very little information is available about MsrB and we focused our attention on Arabidopsis (Arabidopsis thaliana) MsrB proteins. Searching Arabidopsis genome databases, we have identified nine open reading frames encoding proteins closely related to MsrB proteins from bacteria and animal cells. We then analyzed the activity and abundance of the two chloroplastic MsrB proteins, MsrB1 and MsrB2. Both enzymes exhibit an absolute R-stereospecificity for MetSO and a higher catalytic efficiency when using protein-bound MetSO as a substrate than when using free MetSO. Interestingly, we observed that MsrB2 is reduced by thioredoxin, whereas MsrB1 is not. This feature of MsrB1 could result from the lack of the catalytical cysteine (Cys) corresponding to Cys-63 in Escherichia coli MsrB that is involved in the regeneration of Cys-117 through the formation of an intramolecular disulfide bridge followed by thioredoxin reduction. We investigated the abundance of plastidial MsrA and B in response to abiotic (water stress, photooxidative treatment) and biotic (rust fungus) stresses and we observed that MsrA and B protein levels increase in response to the photooxidative treatment. The possible role of plastidic MsrB in the tolerance to oxidative damage is discussed.
Volume 138(2)
Pages 909-22
Published 2005-6-1
DOI 10.1104/pp.105.062430
PII pp.105.062430
PMID 15923321
PMC PMC1150407
MeSH Amino Acid Sequence Arabidopsis / enzymology* Arabidopsis / genetics Arabidopsis Proteins / genetics Arabidopsis Proteins / metabolism Enzyme Induction Gene Expression Regulation, Plant Methionine Sulfoxide Reductases Molecular Sequence Data Multigene Family Mutation Oxidative Stress Oxidoreductases / genetics Oxidoreductases / metabolism* Plant Leaves / metabolism Plastids / enzymology* Plastids / genetics Recombinant Proteins Sequence Alignment Sequence Homology, Amino Acid Substrate Specificity Time Factors
Resource
Arabidopsis / Cultured plant cells, genes pda10343