A cryptic oxidoreductase safeguards oxidative protein folding in Corynebacterium diphtheriae
[2];
[8]
- Department of Microbiology &, Molecular Genetics, University of Texas McGovern Medical School, Houston, TX 77030
- Division of Oral and Systemic Health Sciences, School of Dentistry, University of California, Los Angeles, CA 90095
- Department of Microbiology &, Molecular Genetics, University of Texas McGovern Medical School, Houston, TX 77030, Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX 77030
- Center for Structural Genomics of Infectious Diseases, Consortium for Advanced Science and Engineering, University of Chicago, Chicago, IL 60637, Structural Biology Center, Argonne National Laboratory, Lemont, IL 60439
- Center for Biotechnology, Bielefeld University, D-33615 Bielefeld, Germany
- Department of Microbiology &, Molecular Genetics, University of Texas McGovern Medical School, Houston, TX 77030, Stanford University, Stanford, CA 94305
- Department of Medicine, Neag Comprehensive Cancer Center, University of Connecticut Health Center, Farmington, CT 06030
- Division of Oral and Systemic Health Sciences, School of Dentistry, University of California, Los Angeles, CA 90095, Molecular Biology Institute, University of California, Los Angeles, CA 90095, Department of Microbiology, Immunology &, Molecular Genetics, University of California, Los Angeles, CA 90095
In many gram-positive Actinobacteria, including Actinomyces oris and Corynebacterium matruchotii , the conserved thiol-disulfide oxidoreductase MdbA that catalyzes oxidative folding of exported proteins is essential for bacterial viability by an unidentified mechanism. Intriguingly, in Corynebacterium diphtheriae , the deletion of mdbA blocks cell growth only at 37 °C but not at 30 °C, suggesting the presence of alternative oxidoreductase enzyme(s). By isolating spontaneous thermotolerant revertants of the mdbA mutant at 37 °C, we obtained genetic suppressors, all mapped to a single T-to-G mutation within the promoter region of tsdA , causing its elevated expression. Strikingly, increased expression of tsdA —via suppressor mutations or a constitutive promoter—rescues the pilus assembly and toxin production defects of this mutant, hence compensating for the loss of mdbA . Structural, genetic, and biochemical analyses demonstrated TsdA is a membrane-tethered thiol-disulfide oxidoreductase with a conserved CxxC motif that can substitute for MdbA in mediating oxidative folding of pilin and toxin substrates. Together with our observation that tsdA expression is upregulated at nonpermissive temperature (40 °C) in wild-type cells, we posit that TsdA has evolved as a compensatory thiol-disulfide oxidoreductase that safeguards oxidative protein folding in C. diphtheriae against thermal stress.
- Research Organization:
- Argonne National Laboratory (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- National Institutes of Health (NIH), National Institute of Allergy and Infectious Diseases (NIAID); National Institutes of Health (NIH), National Institute of Dental and Craniofacial Research; USDOE Office of Science (SC), Biological and Environmental Research (BER)
- Grant/Contract Number:
- AC02-06CH11357; HHSN272201700060C; 75N93022C00035
- OSTI ID:
- 1924593
- Alternate ID(s):
- OSTI ID: 1984676
- Journal Information:
- Proceedings of the National Academy of Sciences of the United States of America, Journal Name: Proceedings of the National Academy of Sciences of the United States of America Vol. 120 Journal Issue: 8; ISSN 0027-8424
- Publisher:
- Proceedings of the National Academy of SciencesCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Similar Records
A slow-forming isopeptide bond in the structure of the major pilin SpaD from Corynebacterium diphtheriae has implications for pilus assembly
Structure and Mechanism of LcpA, a Phosphotransferase That Mediates Glycosylation of a Gram-Positive Bacterial Cell Wall-Anchored Protein