title: Mechanical Stability of a High-Affinity Toxin Anchor from the Pathogen Clostridium perfringens.
abstract: The opportunistic pathogen Clostridium perfringens assembles its toxins and carbohydrate-active enzymes by the high-affinity cohesin-dockerin (Coh-Doc) interaction. Coh-Doc interactions characterized previously have shown considerable resilience toward mechanical stress. Here, we aimed to determine the mechanics of this interaction from C. perfringens in the context of a pathogen. Using atomic force microscopy based single-molecule force spectroscopy (AFM-SMFS) we probed the mechanical properties of the interaction of a dockerin from the μ-toxin with the GH84C X82 cohesin domain of C. perfringens. Most probable complex rupture forces were found to be approximately 60 pN and an estimate of the binding potential width was performed. The dockerin was expressed with its adjacent FIVAR (found in various architectures) domain, whose mechanostability we determined to be very similar to the complex. Additionally, fast refolding of this domain was observed. The Coh-Doc interaction from C. perfringens is the mechanically weakest observed to date. Our results establish the relevant force range of toxin assembly mechanics in pathogenic Clostridia.
authors.affiliation: Lehrstuhl für Angewandte Physik and Center for Nanoscience, Ludwig-Maximilians-University , Amalienstr. 54, 80799 Munich, Germany.
authors.forename: Lukas F
authors.initials: LF
authors.lastname: Milles
authors.affiliation: Department of Biomolecular Sciences, The Weizmann Institute of Science , Rehovot 76100, Israel.
authors.forename: Edward A
authors.initials: EA
authors.lastname: Bayer
authors.affiliation: Department of Chemistry, University of Basel , Klingelbergstr. 80, 4056 Basel, Switzerland.|Department of Biosystems Science and Engineering, Eidgenössische Technische Hochschule Zürich (ETH-Zürich) , Mattenstr. 26, 4058 Basel, Switzerland.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Nash
authors.affiliation: Lehrstuhl für Angewandte Physik and Center for Nanoscience, Ludwig-Maximilians-University , Amalienstr. 54, 80799 Munich, Germany.
authors.forename: Hermann E
authors.identifier: 0000-0002-4220-6088
authors.initials: HE
authors.lastname: Gaub
mesh_terms: D003016:Clostridium perfringens / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D008958:Models, Molecular; D055550:Protein Stability; D014118:Toxins, Biological / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification
chemical_list: D014118:Toxins, Biological