title: Characterization of the collagen-like exosporium protein, BclA1, of Clostridium difficile spores.
abstract: Spores of Clostridium difficile are essential for infection, persistence and transmission of C. difficile infections (CDI). Proteins of the surface of C. difficile spores are thought to be essential for initiation and persistence of CDI. In this work, we demonstrate that three C. difficile collagen-like exosporium proteins (BclA) encoded in the C. difficile 630 genome are expressed during sporulation and localize to the spore via their N-terminal domains. Using polyclonal antibodies against the N- and C-terminal domains and full length BclA1 we demonstrate that BclA1 is likely to be localized to the exosporium layer, presumably undergoes post-translational cleavages and might be cross-linked with other exosporium proteins. The collagen-like region of recombinant BclA1 and BclA2 was susceptible to collagenase degradation. Collagenase digestion assay of C. difficile spores suggests that, similarly as in Bacillus anthracis BclA, the N-terminal domain and the C-terminal domain of BclA1 might be buried in the basal layer and oriented to the exosporium surface, respectively. We also demonstrate that the collagen-like BclAs proteins do not contribute to the spore hydrophobicity and its absence slightly increased the adherence of spores to Caco-2 cells. BclA1 was also shown to have poor immunogenic properties. These results provide the first study on the BclA1 collagen-like proteins of C. difficile spores.
authors.affiliation: Laboratorio de Mecanismos de Patogénesis Bacteriana, Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas, Universidad Andrés Bello, República 217, Santiago, Chile.
authors.forename: Marjorie
authors.initials: M
authors.lastname: Pizarro-Guajardo
authors.affiliation: Laboratorio de Mecanismos de Patogénesis Bacteriana, Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas, Universidad Andrés Bello, República 217, Santiago, Chile.
authors.forename: Valeria
authors.initials: V
authors.lastname: Olguín-Araneda
authors.affiliation: Laboratorio de Mecanismos de Patogénesis Bacteriana, Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas, Universidad Andrés Bello, República 217, Santiago, Chile.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Barra-Carrasco
authors.affiliation: Laboratorio de Mecanismos de Patogénesis Bacteriana, Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas, Universidad Andrés Bello, República 217, Santiago, Chile.
authors.forename: Christian
authors.initials: C
authors.lastname: Brito-Silva
authors.affiliation: Department of Biomedical Sciences, Oregon State University, Corvallis, OR, USA; Department of Microbiology, Oregon State University, Corvallis, OR, USA.
authors.forename: Mahfuzur R
authors.initials: MR
authors.lastname: Sarker
authors.affiliation: Laboratorio de Mecanismos de Patogénesis Bacteriana, Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas, Universidad Andrés Bello, República 217, Santiago, Chile; Department of Biomedical Sciences, Oregon State University, Corvallis, OR, USA. Electronic address: daniel.paredes.sabja@gmail.com.
authors.forename: Daniel
authors.initials: D
authors.lastname: Paredes-Sabja
mesh_terms: D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000032:analysis* / Q000737:chemistry / Q000235:genetics; D018938:Caco-2 Cells; D016360:Clostridioides difficile / Q000737:chemistry* / Q000235:genetics; D020869:Gene Expression Profiling; D006801:Humans; D008565:Membrane Proteins / Q000032:analysis* / Q000737:chemistry / Q000235:genetics; D008970:Molecular Weight; D011499:Protein Processing, Post-Translational; D013170:Spores / Q000737:chemistry* / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D008565:Membrane Proteins
keywords: BclA; Clostridium difficile; Exosporium; Spore