title: A Novel MSCRAMM Subfamily in Coagulase Negative Staphylococcal Species.
abstract: Coagulase negative staphylococci (CoNS) are important opportunistic pathogens. Staphylococcus epidermidis, a coagulase negative staphylococcus, is the third leading cause of nosocomial infections in the US. Surface proteins like Microbial Surface Components Recognizing Adhesive Matrix Molecules (MSCRAMMs) are major virulence factors of pathogenic gram positive bacteria. Here, we identified a new chimeric protein in S. epidermidis, that we call SesJ. SesJ represents a prototype of a new subfamily of MSCRAMMs. Structural predictions show that SesJ has structural features characteristic of a MSCRAMM along with a N-terminal repeat region and an aspartic acid containing C-terminal repeat region, features that have not been previously observed in staphylococcal MSCRAMMs but have been found in other surface proteins from gram positive bacteria. We identified and analyzed structural homologs of SesJ in three other CoNS. These homologs of SesJ have an identical structural organization but varying sequence identities within the domains. Using flow cytometry, we also show that SesJ is expressed constitutively on the surface of a representative S. epidermidis strain, from early exponential to stationary growth phase. Thus, SesJ is positioned to interact with protein targets in the environment and plays a role in S. epidermidis virulence.
authors.affiliation: Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston TX, USA.
authors.forename: Srishtee
authors.initials: S
authors.lastname: Arora
authors.affiliation: Division of Infectious Diseases, Department of Medicine, College of Physicians and Surgeons, Columbia University in the City of New York, New York NY, USA.
authors.forename: Anne-Catrin
authors.initials: AC
authors.lastname: Uhlemann
authors.affiliation: Division of Infectious Diseases, Department of Medicine, College of Physicians and Surgeons, Columbia University in the City of New York, New York NY, USA.
authors.forename: Franklin D
authors.initials: FD
authors.lastname: Lowy
authors.affiliation: Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston TX, USA.
authors.forename: Magnus
authors.initials: M
authors.lastname: Hook
keywords: MSCRAMM; N-terminal repeats; Staphylococcus epidermidis; cell wall anchored proteins; coagulase negative staphylococci; structural homologs