Characterization of a novel methionine sulfoxide reductase A from tomato (Solanum lycopersicum), and its protecting role in Escherichia coli

• Published in: BMB reports 2011, 44(12), , pp.805-810
• Main Authors: Dai, Changbo, Kangwon National University, Chuncheon, Republic of Korea, Singh, Naresh Kumar, Kangwon National University, Chuncheon, Republic of Korea, Park, M.H., Kangwon National University, Samcheok, Republic of Korea
• Format: Article
• Language: English
• Subjects: Kinetics parameters; LYCOPERSICON ESCULENTUM; MSRA; Oxidative damage; Reverse phase HPLC; 화학
• ISSN: 1976-6696; 1976-670X
• DOI: 10.5483/BMBRep.2011.44.12.805

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 (SIMSRA2) 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 K∧m and K∧cat values for MSRA2 were observed as 8.5, 25℃, 352 ± 25 μM, and 0.066 ± 0.009 S-¹, respectively. Disk inhibition and growth rate assays indicated that SIMSRA2 may play an essential function in protecting E. coil against oxidative damage.