title: Rational design of inhibitors and activity-based probes targeting Clostridium difficile virulence factor TcdB.
abstract: Clostridium difficile is a leading cause of nosocomial infections. The major virulence factors of this pathogen are the multi-domain toxins TcdA and TcdB. These toxins contain a cysteine protease domain (CPD) that autoproteolytically releases a cytotoxic effector domain upon binding intracellular inositol hexakisphosphate. Currently, there are no known inhibitors of this protease. Here, we describe the rational design of covalent small molecule inhibitors of TcdB CPD. We identified compounds that inactivate TcdB holotoxin function in cells and solved the structure of inhibitor-bound protease to 2.0 Å. This structure reveals the molecular basis of CPD substrate recognition and informed the synthesis of activity-based probes for this enzyme. The inhibitors presented will guide the development of therapeutics targeting C. difficile, and the probes will serve as tools for studying the unique activation mechanism of bacterial toxin CPDs.
authors.affiliation: Department of Chemical and Systems Biology, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, California 94305, USA.
authors.forename: Aaron W
authors.initials: AW
authors.lastname: Puri
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Lupardus
authors.forename: Edgar
authors.initials: E
authors.lastname: Deu
authors.forename: Victoria E
authors.initials: VE
authors.lastname: Albrow
authors.forename: K Christopher
authors.initials: KC
authors.lastname: Garcia
authors.forename: Matthew
authors.initials: M
authors.lastname: Bogyo
authors.forename: Aimee
authors.initials: A
authors.lastname: Shen
mesh_terms: D000494:Allosteric Regulation; D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology; D001426:Bacterial Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D001427:Bacterial Toxins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D001665:Binding Sites; D016360:Clostridioides difficile / Q000201:enzymology; D003198:Computer Simulation; D018360:Crystallography, X-Ray; D057056:Cysteine Proteases / Q000737:chemistry; D015853:Cysteine Proteinase Inhibitors / Q000737:chemistry* / Q000494:pharmacology; D015195:Drug Design; D015335:Molecular Probes / Q000737:chemistry / Q000494:pharmacology; D010833:Phytic Acid / Q000737:chemistry; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D013329:Structure-Activity Relationship
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D015853:Cysteine Proteinase Inhibitors; D015335:Molecular Probes; C031815:toxB protein, Clostridium difficile; D010833:Phytic Acid; D057056:Cysteine Proteases