Structure of the cell-binding component of the Clostridium difficile binary toxin reveals a di-heptamer macromolecular assembly
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- City University of New York Advanced Science Research Center, City University of New York, New York, NY 10017,, PhD Program in Biochemistry, The Graduate Center, City University of New York, New York, NY 10017,
- Department of Biochemistry &, Molecular Biology, University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201,, Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850,, The Center for Biomolecular Therapeutics, The University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201,
- Department of Biochemistry &, Molecular Biology, University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201,, The Center for Biomolecular Therapeutics, The University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201,
- City University of New York Advanced Science Research Center, City University of New York, New York, NY 10017,
- Department of Biochemistry &, Molecular Biology, University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201,
- National Institute of Standards, Rockville, MD 20899,
- University of Maryland School of Pharmacy, University of Maryland, Baltimore, MD 21201,
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850,, The Center for Biomolecular Therapeutics, The University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201,, University of Maryland School of Pharmacy, University of Maryland, Baltimore, MD 21201,
- Department of Chemistry &, Biochemistry, University of Maryland, College Park, MD 20742,
- Merck &, Co., Inc., Kenilworth, NJ 07033,
- City University of New York Advanced Science Research Center, City University of New York, New York, NY 10017,, PhD Program in Biochemistry, The Graduate Center, City University of New York, New York, NY 10017,, PhD Program in Chemistry, The Graduate Center, City University of New York, New York, NY 10017,, Department of Chemistry &, Biochemistry, City College of New York, New York, NY 10031
Targeting Clostridium difficile infection is challenging because treatment options are limited, and high recurrence rates are common. One reason for this is that hypervirulent C. difficile strains often have a binary toxin termed the C. difficile toxin, in addition to the enterotoxins TsdA and TsdB. The C. difficile toxin has an enzymatic component, termed CDTa, and a pore-forming or delivery subunit termed CDTb. CDTb was characterized here using a combination of single-particle cryoelectron microscopy, X-ray crystallography, NMR, and other biophysical methods. In the absence of CDTa, 2 di-heptamer structures for activated CDTb (1.0 MDa) were solved at atomic resolution, including a symmetric ( Sym CDTb; 3.14 Å) and an asymmetric form ( Asym CDTb; 2.84 Å). Roles played by 2 receptor-binding domains of activated CDTb were of particular interest since the receptor-binding domain 1 lacks sequence homology to any other known toxin, and the receptor-binding domain 2 is completely absent in other well-studied heptameric toxins (i.e., anthrax). For Asym CDTb, a Ca 2+ binding site was discovered in the first receptor-binding domain that is important for its stability, and the second receptor-binding domain was found to be critical for host cell toxicity and the di-heptamer fold for both forms of activated CDTb. Together, these studies represent a starting point for developing structure-based drug-design strategies to target the most severe strains of C. difficile .
- Research Organization:
- SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States). Stanford Synchrotron Radiation Lightsource (SSRL)
- Sponsoring Organization:
- USDOE Office of Science (SC), Biological and Environmental Research (BER); National Institutes of Health (NIH); National Institute of General Medical Sciences (NIGMS); USDOE Office of Science (SC), Basic Energy Sciences (BES); National Science Foundation (NSF)
- Grant/Contract Number:
- AC02-76SF00515; R35GM133598
- OSTI ID:
- 1581008
- Alternate ID(s):
- OSTI ID: 1625064
- 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. 117 Journal Issue: 2; ISSN 0027-8424
- Publisher:
- Proceedings of the National Academy of SciencesCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
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