A Novel MSCRAMM Subfamily in Coagulase Negative Staphylococcal Species.

Srishtee Arora,Anne-Catrin Uhlemann,Franklin D Lowy,Magnus Hook

doi:10.3389/fmicb.2016.00540

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.

Highlights

Coagulase negative staphylococci (CoNS), which colonize human skin and mucus membranes, are recognized as important opportunistic pathogens
We here report on the discovery of a previously unknown cell wall-anchored (CWA) S. epidermidis protein that we demonstrate is a prototype of a novel subfamily of CoNS MSCRAMMs
While examining the sequence variation of SdrG in published S. epidermidis genomes, we discovered a gene encoding a SdrGlike but clearly distinct CWA protein that we have called SesJ (GenBank accession number: KU935462) according to the established nomenclature

Summary

A Novel MSCRAMM Subfamily in Coagulase Negative Staphylococcal Species

Coagulase negative staphylococci (CoNS) are important opportunistic pathogens. 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. SesJ is positioned to interact with protein targets in the environment and plays a role in S. epidermidis virulence

INTRODUCTION

MATERIALS AND METHODS

RESULTS

DISCUSSION