Identification of disulfide reductases in Campylobacterales: a bioinformatics investigation

Abstract

Disulfide reductases of host-colonising bacteria are involved in the expression of virulence factors, resistance to drugs, and elimination of toxic compounds. Large-scale genome analyses of 281 prokaryotes identified CXXC and CXXC-derived motifs in each microorganism. The total number of these motifs showed correlations with genome size and oxygen tolerance of the prokaryotes. Specific bioinformatic analyses served to identify putative disulfide reductases in the Campylobacterales Campylobacter jejuni, Helicobacter pylori, Wolinella succinogenes and Arcobacter butzleri which colonise the gastrointestinal tract of higher animals. Three filters applied to the genomes of these species yielded 35, 25, 28 and 34 genes, respectively, encoding proteins with the characteristics of disulfide reductases. Ten proteins were common to the four species, including four belonging to the thioredoxin system. The presence of thioredoxin reductase activities was detected in the four bacterial species by observing dithiobis-2-nitrobenzoic acid reduction with beta-nicotinamide adenine dinucleotide phosphate as cofactor. Phylogenetic analyses of the thioredoxin reductases TrxB(1) and TrxB(2) of the four Campylobacterales were performed. Their TrxB(1) proteins were more closely related to those of Firmicutes than to the corresponding proteins of other Proteobacteria. The Campylobacterales TrxB(2) proteins were closer to glutathione reductases of other organisms than to their respective TrxB(1) proteins. The phylogenetic features of the Campylobacterales thioredoxin reductases suggested a special role for these enzymes in the physiology of these bacteria.

Insights into the Mode of Action of Benzyl Isothiocyanate on Campylobacter jejuni

“…Motifs such as CXXC, CXXS, or CXXT are commonly found in disulfide reductases or enzymes with metal coordination centers (78,79). The oxygen requirement and oxygen sensitivity influence the number of enzymes with CXXC/CXXS/CXXT motifs; these motifs are found significantly more frequently in the proteins of microaerobes and anaerobes than in aerobic bacteria (80,81). Indeed, approximately 40% of the proteins of C. jejuni contain at least one of these motifs (80); therefore, both the microaerophilic phenotype of C. jejuni and the large number of cysteine-based motifs encoded by its genome can explain the higher ITC sensitivity of this organism than of other prokaryotes such as P. aeruginosa (29; C. Baysse, unpublished data).…”

Identification of Immunogenic and Virulence-Associated Campylobacter jejuni Proteins

“…Flavodoxin (Cj1382c) was among the identified proteins but it was not examined in a mouse vaccination-challenge experiment. Flavodoxin and Cj1292 (dCTP deaminase) were identified as being among the proteins expressed in an efficient chicken colonizing strain when compared to a poor colonizer (15). Furthermore, this study determined that Cj0203 was overexpressed along with important surface adhesins such as CadF and FlaA (9,15).…”

Comparative Roles of the Two Helicobacter pylori Thioredoxins in Preventing Macromolecule Damage

“…Maintaining the redox balance within H. pylori is important for cell viability, growth, and metabolism (51). This renders the Trx system essential for survival under oxidative stress, as this is the only disulfide reductase system present in H. pylori.…”