Detection, Distribution and Characterization of Novel Superoxide Dismutases from Yersinia enterocolitica Biovar 1A

Abstract

BackgroundSuperoxide dismutases (SODs) cause dismutation of superoxide radicals to hydrogen peroxide and oxygen. Besides protecting the cells against oxidative damage by endogenously generated oxygen radicals, SODs play an important role in intraphagocytic survival of pathogenic bacteria. The complete genome sequences of Yersinia enterocolitica strains show presence of three different sod genes. However, not much is known about the types of SODs present in Y. enterocolitica, their characteristics and role in virulence and intraphagocytic survival of this organism.Methodology/Principal FindingsThis study reports detection and distribution of the three superoxide dismutase (sodA, sodB and sodC) genes in 59 strains of Y. enterocolitica and related species. The majority (94%) of the strains carried all three genes and constitutive expression of sodA and sodB was detected in 88% of the strains. Expression of sodC was not observed in any of the strains. The sodA, sodB and sodC genes of Y. enterocolitica were cloned in pET28a (+) vector. Recombinant SodA (82 kDa) and SodB (21 kDa) were expressed as homotetramer and monomer respectively, and showed activity over a broad range of pH (3.0–8.0) and temperature (4–70°C). SodA and SodB showed optimal activity at 4°C under acidic pH of 6.0 and 4.0 respectively. The secondary structures of recombinant SodA and SodB were studied using circular dichroism. Production of YeSodC was not observed even after cloning and expression in E. coli BL21(DE3) cells. A SodA− SodB− Escherichia coli strain which was unable to grow in medium supplemented with paraquat showed normal growth after complementation with Y. enterocolitica SodA or SodB.Conclusions/SignificanceThis is the first report on the distribution and characterization of superoxide dismutases from Y. enterocolitica. The low pH optima of both SodA and SodB encoded by Y. enterocolitica seem to implicate their role in acidic environments such as the intraphagocytic vesicles.

Structural characterization of a pathogenicity-related superoxide dismutase codified by a probably essential gene in Xanthomonas citri subsp. citri

“…With respect to catalysis, XcSOD presented a specific activity of 11609 U/mg, very similar to the value of 12800 U/mg reported for Yersinia enterocolitica SodA [73], a tetrameric MnSOD with which it shares 57% sequence identity. The dimeric MnSOD from Bacillus subtilis , used here for molecular replacement, presents a slightly lower activity but is nevertheless still of the same order of magnitude (4590 U/mg) [74].…”

Mechanisms of Bacterial Tolerance and Persistence in the Gastrointestinal and Respiratory Environments

“…The Shigella dysenteriae 1 toxin produces intestinal infection via a decrease in the endogenous intestinal protection against ROS (65). Two new SODs associated with survival in acidic environments, including that in intraphagocytic vesicles, have been described for Yersinia enterocolitica (66). The siderophore yersiniabactin increases the virulence of Y. enterocolitica and blocks the development of the ROS response through eukaryotic cells (leukocytes, monocytes, and macrophages) (67).…”

Comparative genomic analysis of Myroides odoratimimus isolates

“…with fibronectin on host cells (Viale et al, 2014). Superoxide dismutases (SODs) protect the bacteria from oxidative damage by converting endogenously generated superoxide radicals into hydrogen peroxide and oxygen, are indispensable for intraphagocytic viability for pathogenic bacteria (Dhar, Gupta, & Virdi, 2013), SodB is required for colonization of Helicobacter pylori in the stomach (Tsugawa et al, 2015). (Ghazaei, 2017).…”