title: A family of fibrinogen-binding MSCRAMMs from Enterococcus faecalis.
abstract: We report that three (EF0089, EF2505 and EF1896, renamed here Fss1, Fss2 and Fss3, respectively, for Enterococcus faecalis surface protein) of the recently predicted MSCRAMMs (microbial surface components recognizing adhesive matrix molecules) in E. faecalis strain V583 bind fibrinogen (Fg). Despite an absence of extensive primary sequence homology, the three proteins appear to be related structurally. Within the N-terminal regions of the three enterococcal proteins, we identified pairs of putative IgG-like modules with a high degree of predicted structural similarity to the Fg-binding N2 and N3 domains of the staphylococcal MSCRAMMs ClfA and SdrG. A second N2N3-like segment was predicted in Fss1. Far-UV circular dichroism spectroscopy revealed that all four predicted N2N3-like regions are composed mainly of beta-sheets with only a minor proportion of alpha-helices, which is characteristic of Ig-like folded domains. Three of the four identified enterococcal N2N3-like regions showed potent dose-dependent binding to Fg. However, the specificity of the Fg-binding MSCRAMMs differs, as indicated by far-Western blots, which showed that recombinant segments of the MSCRAMMs bound different Fg polypeptide chains. Enterococci grown in serum-supplemented broth adhere to Fg-coated surfaces, and inactivation in strain OG1RF of the gene encoding Fss2 resulted in reduced adherence, whilst complementation of the mutant restored full Fg adherence. Thus, E. faecalis contains a family of MSCRAMMs that structurally and functionally resemble the Fg-binding MSCRAMMs of staphylococci.
authors.affiliation: Center for the Study of Emerging and Re-emerging Pathogens, University of Texas Medical School, Houston, TX, USA.|Division of Infectious Diseases, Department of Internal Medicine, University of Texas Medical School, Houston, TX, USA.|Center for Extracellular Matrix Biology, Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, TX, USA.
authors.forename: Jouko
authors.initials: J
authors.lastname: Sillanpää
authors.affiliation: Center for the Study of Emerging and Re-emerging Pathogens, University of Texas Medical School, Houston, TX, USA.|Division of Infectious Diseases, Department of Internal Medicine, University of Texas Medical School, Houston, TX, USA.
authors.forename: Sreedhar R
authors.initials: SR
authors.lastname: Nallapareddy
authors.affiliation: Center for Extracellular Matrix Biology, Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, TX, USA.
authors.forename: Janeu
authors.initials: J
authors.lastname: Houston
authors.affiliation: Center for Extracellular Matrix Biology, Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, TX, USA.
authors.forename: Vannakambadi K
authors.initials: VK
authors.lastname: Ganesh
authors.affiliation: Center for the Study of Emerging and Re-emerging Pathogens, University of Texas Medical School, Houston, TX, USA.|Division of Infectious Diseases, Department of Internal Medicine, University of Texas Medical School, Houston, TX, USA.
authors.forename: Agathe
authors.initials: A
authors.lastname: Bourgogne
authors.affiliation: Center for the Study of Emerging and Re-emerging Pathogens, University of Texas Medical School, Houston, TX, USA.|Division of Infectious Diseases, Department of Internal Medicine, University of Texas Medical School, Houston, TX, USA.
authors.forename: Kavindra V
authors.initials: KV
authors.lastname: Singh
authors.affiliation: Department of Microbiology and Molecular Genetics, University of Texas Medical School, Houston, TX, USA.|Center for the Study of Emerging and Re-emerging Pathogens, University of Texas Medical School, Houston, TX, USA.|Division of Infectious Diseases, Department of Internal Medicine, University of Texas Medical School, Houston, TX, USA.
authors.forename: Barbara E
authors.initials: BE
authors.lastname: Murray
authors.affiliation: Center for Extracellular Matrix Biology, Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, TX, USA.
authors.forename: Magnus
authors.initials: M
authors.lastname: Höök
mesh_terms: D018829:Adhesins, Bacterial / Q000737:chemistry / Q000378:metabolism*; D000818:Animals; D026481:Blotting, Far-Western; D002942:Circular Dichroism; D013293:Enterococcus faecalis / Q000378:metabolism*; D005109:Extracellular Matrix / Q000378:metabolism; D005340:Fibrinogen / Q000378:metabolism*; D006801:Humans; D051379:Mice; D005810:Multigene Family; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000378:metabolism; D020539:Sequence Analysis, Protein
chemical_list: D018829:Adhesins, Bacterial; D011994:Recombinant Proteins; D005340:Fibrinogen