The red-ox status of a penicillin-binding protein is an on/off switch for spore peptidoglycan synthesis in Bacillus subtilis.
Thiol-disulphide oxidoreductases catalyse the formation or breakage of disulphide bonds to control the red-ox status of a variety of proteins. Their activity is compartmentalized, as exemplified by the distinct roles these enzymes play in the cytoplasm and periplasm of Gram-negative bacteria. In this issue of Molecular Microbiology, an article from Lars Hederstedt and collaborators at Lund University sheds light on another member of this superfamily of proteins, the thioredoxin-like protein StoA from Bacillus subtilis. Interestingly, StoA function is required in yet another subcellular compartment: the intermembrane space that separates forespores from mother cells in endospore-forming bacteria. Specifically, this study demonstrates that the high-molecular-weight penicillin-binding protein SpoVD, which contains two exposed cysteine residues and whose extracellular domain is located in the intermembrane space, is a substrate of StoA. As formation of a disulphide bond most likely inactivates SpoVD activity, the converse breakage of that bond in a process catalysed by StoA appears to be the trigger that initiates peptidoglycan synthesis in sporulating cells.
Eichenberger
Patrick
P
Center for Genomics and Systems Biology, Department of Biology, New York University, 1009 Silver Center, New York, NY 10003, USA. pe19@nyu.edu
D001412:Bacillus subtilis / Q000201:enzymology / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism*; D004220:Disulfides / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000378:metabolism*; D008954:Models, Biological; D010084:Oxidation-Reduction; D046915:Penicillin-Binding Proteins / Q000378:metabolism*; D010457:Peptidoglycan / Q000096:biosynthesis*; D019704:Protein Disulfide-Isomerases / Q000378:metabolism*; D013171:Spores, Bacterial / Q000201:enzymology / Q000378:metabolism*
D001426:Bacterial Proteins; D004220:Disulfides; D026901:Membrane Transport Proteins; D046915:Penicillin-Binding Proteins; D010457:Peptidoglycan; C085450:SpoVD protein, Bacillus subtilis; D019704:Protein Disulfide-Isomerases