A Novel Insight into the Oxidoreductase Activity of Helicobacter pylori HP0231 Protein

Abstract

BackgroundThe formation of a disulfide bond between two cysteine residues stabilizes protein structure. Although we now have a good understanding of the Escherichia coli disulfide formation system, the machineries at work in other bacteria, including pathogens, are poorly characterized. Thus, the objective of this work was to improve our understanding of the disulfide formation machinery of Helicobacter pylori, a leading cause of ulcers and a risk factor for stomach cancer worldwide.Methods and ResultsThe protein HP0231 from H. pylori, a structural counterpart of E. coli DsbG, is the focus of this research. Its function was clarified by using a combination of biochemical, microbiological and genetic approaches. In particular, we determined the biochemical properties of HP0231 as well as its redox state in H. pylori cells.ConclusionAltogether our results show that HP0231 is an oxidoreductase that catalyzes disulfide bond formation in the periplasm. We propose to call it HpDsbA.

Characterization of Helicobacter pylori HP0231 (DsbK): role in disulfide bond formation, redox homeostasis and production of Helicobacter cystein‐rich protein HcpE

“…The experiments above highlight HcpE as a substrate for DsbK and strongly suggest a role for DsbK in assisting disulfide bond formation in HcpE prior to secretion. This is consistent with the fact that DsbK is a putative DsbG protein potentially involved in the isomerization of non native disulfide bonds, but its precise biochemical function (role in disulfide bond formation and DsbG vs. DsbA type of activity) is still up for debate (Yoon et al ., ; Roszczenko et al ., ). DsbK has a predicted Sec signal peptide (Kim et al ., ) that should support its transfer into the periplasm where it could carry out its Dsb function.…”

“…Our work provides functional evidence that DsbK has Dsb activity on a surrogate substrate and suggests a DsbA‐like activity (oxidase) rather than a DsbG‐like activity (isomerase) when expressed in E. coli . Although our finding of DsbA‐type activity for DsbK was unexpected in view of its homologies to E. coli DsbG (Yoon et al ., ), it is in agreement with functional data obtained using insulin as a substrate (Roszczenko et al ., ).…”

“…In line with the fact that Dsb proteins are often involved in bacterial pathogenicity (Heras et al ., ), HP0595 and HP0231 are important for gastric colonization in mice (Sabarth et al ., ; Godlewska et al ., ). Recent structural data (Yoon et al ., ) support our modeling‐based prediction of HP0231 as a DsbG homologue, but recent functional data suggest that HP0231 has DsbA‐like activity (Roszczenko et al ., ). Therefore, further investigations are necessary to clarify the issue.…”

Salmonellaas a vaccine delivery vehicle

“…Aebeischer and associates utilized a thyA derivative of Ty21a to deliver two different Helicobacter pylori antigens, UreAB (urease) and HP0231, a protective antigen related to E. coli DsbG [85], whose genes were carried on plasmids utilizing a ThyA + selection system [86]. The study was set up in two parts, a preliminary trial with 20 subjects and a secondary study using 47 subjects.…”

Purification, crystallization and preliminary crystallographic investigation of FrnE, a disulfide oxidoreductase fromDeinococcus radiodurans

“…Recently, it has been argued that the protection of proteins from oxidative damage is the key to the radiation resistance shown by D. radiodurans (Daly, 2009;Krisko & Radman, 2013). Dsb proteins have been shown to be the part of the cell machinery that protects proteins from oxidative damage in other systems (Roszczenko et al, 2012;Denoncin et al, 2014). The D. radiodurans genome also encodes putative Dsb homologues (Heras et al, 2009); however, very little is known about their roles.…”