Thiol-disulphide oxidoreductase modules in the low-GC Gram-positive bacteria.
Disulphide bond formation catalysed by thiol-disulphide oxidoreductases (TDORs) is a universally conserved mechanism for stabilizing extracytoplasmic proteins. In Escherichia coli, disulphide bond formation requires a concerted action of distinct TDORs in thiol oxidation and subsequent quinone reduction. TDOR function in other bacteria has remained largely unexplored. Here we focus on TDORs of low-GC Gram-positive bacteria, in particular DsbA of Staphylococcus aureus and BdbA-D of Bacillus subtilis. Phylogenetic analyses reveal that the homologues DsbA and BdbD cluster in distinct groups typical for Staphylococcus and Bacillus species respectively. To compare the function of these TDORs, DsbA was produced in various bdb mutants of B. subtilis. Next, we assessed the ability of DsbA to sustain different TDOR-dependent processes, including heterologous secretion of E. coli PhoA, competence development and bacteriocin (sublancin 168) production. The results show that DsbA can function in all three processes. While BdbD needs a quinone oxidoreductase for activity, DsbA activity appears to depend on redox-active medium components. Unexpectedly, both quinone oxidoreductases of B. subtilis are sufficient to sustain production of sublancin. Moreover, DsbA can functionally replace these quinone oxidoreductases in sublancin production. Taken together, our unprecedented findings imply that TDOR systems of low-GC Gram-positive bacteria have a modular composition.
Kouwen
Thijs R H M
TR
Department of Medical Microbiology, University Medical Center Groningen and University of Groningen, Hanzeplein 1, PO Box 30001, 9700 RB Groningen, The Netherlands.
van der Goot
Annemieke
A
Dorenbos
Ronald
R
Winter
Theresa
T
Antelmann
Haike
H
Plaisier
Marie-Claire
MC
Quax
Wim J
WJ
van Dijl
January Maarten
JM
Dubois
Jean-Yves F
JY
D000469:Alkaline Phosphatase / Q000235:genetics / Q000378:metabolism; D001412:Bacillus subtilis / Q000201:enzymology* / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001430:Bacteriocins / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D017353:Gene Deletion; D005816:Genetic Complementation Test; D006020:Glycopeptides; D005810:Multigene Family; D010455:Peptides / Q000378:metabolism; D010802:Phylogeny; D011490:Protein Disulfide Reductase (Glutathione) / Q000235:genetics* / Q000378:metabolism; D019704:Protein Disulfide-Isomerases / Q000235:genetics* / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013211:Staphylococcus aureus / Q000201:enzymology* / Q000378:metabolism
D001426:Bacterial Proteins; D001430:Bacteriocins; D029968:Escherichia coli Proteins; D006020:Glycopeptides; D010455:Peptides; C114602:sublancin 168; C450431:BdbD protein, Bacillus subtilis; D011490:Protein Disulfide Reductase (Glutathione); D000469:Alkaline Phosphatase; C114089:phoA protein, E coli; D019704:Protein Disulfide-Isomerases