title: The CWB2 Cell Wall-Anchoring Module Is Revealed by the Crystal Structures of the Clostridium difficile Cell Wall Proteins Cwp8 and Cwp6.
abstract: Bacterial cell wall proteins play crucial roles in cell survival, growth, and environmental interactions. In Gram-positive bacteria, cell wall proteins include several types that are non-covalently attached via cell wall binding domains. Of the two conserved surface-layer (S-layer)-anchoring modules composed of three tandem SLH or CWB2 domains, the latter have so far eluded structural insight. The crystal structures of Cwp8 and Cwp6 reveal multi-domain proteins, each containing an embedded CWB2 module. It consists of a triangular trimer of Rossmann-fold CWB2 domains, a feature common to 29 cell wall proteins in Clostridium difficile 630. The structural basis of the intact module fold necessary for its binding to the cell wall is revealed. A comparison with previously reported atomic force microscopy data of S-layers suggests that C. difficile S-layers are complex oligomeric structures, likely composed of several different proteins.
authors.affiliation: Department of Biochemistry, Molecular and Structural Biology, Jožef Stefan Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia.
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Usenik
authors.affiliation: Department of Biochemistry, Molecular and Structural Biology, Jožef Stefan Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia; Centre of Excellence for Integrated Approaches in Chemistry and Biology of Proteins (CIPKeBiP), Jamova cesta 39, 1000 Ljubljana, Slovenia.
authors.forename: Miha
authors.initials: M
authors.lastname: Renko
authors.affiliation: Department of Biochemistry, Molecular and Structural Biology, Jožef Stefan Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia; Centre of Excellence for Integrated Approaches in Chemistry and Biology of Proteins (CIPKeBiP), Jamova cesta 39, 1000 Ljubljana, Slovenia.
authors.forename: Marko
authors.initials: M
authors.lastname: Mihelič
authors.affiliation: Department of Biochemistry, Molecular and Structural Biology, Jožef Stefan Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia.
authors.forename: Nataša
authors.initials: N
authors.lastname: Lindič
authors.affiliation: National Institute of Chemistry, Hajdrihova 19, 1001 Ljubljana, Slovenia.
authors.forename: Jure
authors.initials: J
authors.lastname: Borišek
authors.affiliation: National Institute of Chemistry, Hajdrihova 19, 1001 Ljubljana, Slovenia.
authors.forename: Andrej
authors.initials: A
authors.lastname: Perdih
authors.affiliation: Department of Biochemistry, Molecular and Structural Biology, Jožef Stefan Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia; Centre of Excellence for Integrated Approaches in Chemistry and Biology of Proteins (CIPKeBiP), Jamova cesta 39, 1000 Ljubljana, Slovenia.
authors.forename: Gregor
authors.initials: G
authors.lastname: Pretnar
authors.affiliation: Macromolecular Crystallography Group, Helmholtz Zentrum for Materials and Energy Berlin, Albert-Einstein-Straße 15, 12489 Berlin, Germany.
authors.forename: Uwe
authors.initials: U
authors.lastname: Müller
authors.affiliation: Department of Biochemistry, Molecular and Structural Biology, Jožef Stefan Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia; Centre of Excellence for Integrated Approaches in Chemistry and Biology of Proteins (CIPKeBiP), Jamova cesta 39, 1000 Ljubljana, Slovenia. Electronic address: dusan.turk@ijs.si.
authors.forename: Dušan
authors.initials: D
authors.lastname: Turk
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry*; D001665:Binding Sites; D002473:Cell Wall / Q000378:metabolism*; D016360:Clostridioides difficile / Q000737:chemistry / Q000378:metabolism*; D017124:Conserved Sequence; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D011485:Protein Binding; D017434:Protein Structure, Tertiary
chemical_list: D001426:Bacterial Proteins
keywords: Gram-positive bacteria; SlpA homolog; amidase; cell wall binding domain 2 (CWB2); cell wall protein; crystal structure; human pathogen Clostridium difficile; surface-layer (S-layer) proteins; toprim domain module; trimeric complexes