title: Characterization of a novel methionine sulfoxide reductase A from tomato (Solanum lycopersicum ), and its protecting role in Escherichia coli.
abstract: Methionine sulfoxide reductase A (MSRA) is a ubiquitous enzyme that has been demonstrated to reduce the S enantiomer of methionine sulfoxide (MetSO) to methionine (Met) and can protect cells against oxidative damage. In this study, we isolated a novel MSRA (SlMSRA2) from Micro-Tom (Solanum lycopersicum L. cv. Micro-Tom) and characterized it by subcloning the coding sequence into a pET expression system. Purified recombinant protein was assayed by HPLC after expression and refolding. This analysis revealed the absolute specificity for methionine-S-sulfoxide and the enzyme was able to convert both free and protein-bound MetSO to Met in the presence of DTT. In addition, the optimal pH, appropriate temperature, and Km and Kcat values for MSRA2 were observed as 8.5, 25oC, 352 ± 25 μM, and 0.066 ± 0.009 S(-1), respectively. Disk inhibition and growth rate assays indicated that SlMSRA2 may play an essential function in protecting E. coli against oxidative damage.
authors.affiliation: Department of Mechanical Engineering, College of Biomedical Science, Kangwon National University, Samcheok 245-711, Korea.
authors.forename: Changbo
authors.initials: C
authors.lastname: Dai
authors.forename: Naresh Kumar
authors.initials: NK
authors.lastname: Singh
authors.forename: Myungho
authors.initials: M
authors.lastname: Park
mesh_terms: D004926:Escherichia coli / Q000254:growth & development / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D018551:Solanum lycopersicum / Q000201:enzymology*; D051150:Methionine Sulfoxide Reductases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D013696:Temperature
chemical_list: D011994:Recombinant Proteins; D051150:Methionine Sulfoxide Reductases