The crystal structure of the superoxide dismutase from Helicobacter pylori reveals a structured C-terminal extension

Helicobacter pyloridefense against oxidative attack

“…(1). However, all ironcontaining SODs have a conserved structure, particularly within the active site (32,52). There is little homology with human SOD forms, with protein sequence analysis revealing homology of 11%, 30%, and 3% with human SOD1, SOD2, and SOD3, respectively (36).…”

“…This hypothetical mechanism, originally suggested to explain urease release, proposes that a proportion of H. pylori within a colony undergoes spontaneous autolysis to release enzymes that aid the remaining bacteria in colonization (29). This second mechanism would fit with the presence of a 20-residue extended COOH-terminal tail on Hp-SOD, which Esposito et al (32) postulated may be involved in adsorption to the bacterial outer membrane.…”

Oxidative and nitrosative stress defences ofHelicobacterandCampylobacterspecies that counteract mammalian immunity

“…At certain stages of H. pylori growth, SodB seems to be localised on the cell surface and even attached to the flagellar sheath, although no export sequence has been identified in its amino acid sequence (Spiegelhalder et al 1993). However, H. pylori SodB has a C-terminus extension, which is absent in the E. coli and P. ovalis SodB structures (Esposito et al 2008) but present in C. jejuni SodB (Pesci, Cottle and Pickett 1994), that has been proposed to play a role in SodB cell surface location in H. pylori. Alternatively, the serine and/or tyrosine residues located in the Cterminal tail may serve as phosphorylation sites as phosphoproteome studies showed that C. jejuni and H. pylori SodB are major (2015) phosphoproteins (Voisin et al 2007).…”

“…Unlike other enteric pathogens such as Escherichia coli, Shigella and Salmonella, H. pylori encodes only one cytoplasmic Fe-superoxide dismutase (SodB). The protein is a dimer consisting of two identical subunits and displays 53% and 48% amino acid sequence identity to the structurally characterised SodB enzymes of E. coli and Pseudomonas ovalis, respectively (Ringe et al 1983;Lah et al 1995;Esposito et al 2008;Sheng et al 2014). At certain stages of H. pylori growth, SodB seems to be localised on the cell surface and even attached to the flagellar sheath, although no export sequence has been identified in its amino acid sequence (Spiegelhalder et al 1993).…”

Molecular Approaches and Modern Clinical Strategies for the Management of Helicobacter pylori Infection in Japan

“…22 Ferrous iron (Fe 2+ ), an essential cofactor for many enzymes and metalloproteins, is necessary for the basal functions of all cells as well as for SodB activation. 23 We recently demonstrated that the FecA1 protein, a Fe 3+ -dicitrate transporter homolog, is essential for SodB activation but not for the bioactivity of H. pylori. 24 fecA1 mRNA expression is derepressed in metronidazole-resistant H. pylori strains with mutations in Fur.…”