Periplasmic methionine sulfoxide reductase (MsrP)—a secondary factor in stress survival and virulence of Salmonella Typhimurium

• Published in: FEMS microbiology letters 2023-01, Vol.370
• Main Authors: Chandra, Hari Balaji, Shome, Arijit, Sahoo, Raj, Apoorva, S, Bhure, Sanjeev Kumar, Mahawar, Manish
• Format: Article
• Language: English
• Subjects: Carbonyl compounds; Carbonyls; Chloramine-T; Colonization; Hypersensitivity; Leukocytes (neutrophilic); Localization; Methionine; Mutants; Oxidants; Oxidation; Oxidative stress; Oxidizing agents; Proteins; Reductases; Residues; Salmonella; Salmonella Typhimurium; Sulfoxides; Survival; Virulence
• ISSN: 1574-6968; 0378-1097; 1574-6968
• DOI: 10.1093/femsle/fnad063

Abstract Among others, methionine residues are highly susceptible to host-generated oxidants. Repair of oxidized methionine (Met-SO) residues to methionine (Met) by methionine sulfoxide reductases (Msrs) play a chief role in stress survival of bacterial pathogens, including Salmonella Typhimurium. Periplasmic proteins, involved in many important cellular functions, are highly susceptible to host-generated oxidants. According to location in cell, two types of Msrs, cytoplasmic and periplasmic are present in S. Typhimurium. Owing to its localization, periplasmic Msr (MsrP) might play a crucial role in defending the host-generated oxidants. Here, we have assessed the role of MsrP in combating oxidative stress and colonization of S. Typhimurium. ΔmsrP (mutant strain) grew normally in in-vitro media. In comparison to S. Typhimurium (wild type), mutant strain showed mild hypersensitivity to HOCl and chloramine-T (ChT). Following exposure to HOCl, mutant strain showed almost similar protein carbonyl levels (a marker of protein oxidation) as compared to S. Typhimurium strain. Additionally, ΔmsrP strain showed higher susceptibility to neutrophils than the parent strain. Further, the mutant strain showed very mild defects in survival in mice spleen and liver as compared to wild-type strain. In a nutshell, our results indicate that MsrP plays only a secondary role in combating oxidative stress and colonization of S. Typhimurium. Periplasmic Msr mutant (ΔmsrP) of Salmonella Typhimurium strain does not show growth defect in various in vitro media like LB and M9 broth media as compared to the wild-type strain (Msr–Methionine sulfoxide reductase).