The Plasmin-Sensitive Protein Pls in Methicillin-Resistant Staphylococcus aureus (MRSA) Is a Glycoprotein

PLoS Pathogens

Muzaffar Hussain¹  Andreas Peschel²  Christine Heilmann³  Guoqing Xia⁴  Simon Foster⁵  Gottfried Pohlentz⁵  Isabelle Bleiziffer⁵  Julian Eikmeier⁶  Kathryn McAulay⁶  Georg Peters⁷ 

[1] Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom;Division of Infection, Immunity and Respiratory Medicine, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom;German Center for Infection Research (DZIF), partner site Tübingen, University of Tübingen, Tübingen, Germany;Institute for Hygiene, University of Münster, Münster, Germany;Institute of Medical Microbiology, University of Münster, Münster, Germany;Interdisciplinary Center for Clinical Research (IZKF), University of Münster, Münster, Germany;Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany

关键词: Staphylococcus aureus;    Glycosylation;    Bacterial biofilms;    Biofilms;    Plasmid construction;    Methicillin-resistant Staphylococcus aureus;    Glycoproteins;    Staphylococcus;   

DOI  :  10.1371/journal.ppat.1006110

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Most bacterial glycoproteins identified to date are virulence factors of pathogenic bacteria, i.e. adhesins and invasins. However, the impact of protein glycosylation on the major human pathogen Staphylococcus aureus remains incompletely understood. To study protein glycosylation in staphylococci, we analyzed lysostaphin lysates of methicillin-resistant Staphylococcus aureus (MRSA) strains by SDS-PAGE and subsequent periodic acid-Schiff’s staining. We detected four (>300, ∼250, ∼165, and ∼120 kDa) and two (>300 and ∼175 kDa) glycosylated surface proteins with strain COL and strain 1061, respectively. The ∼250, ∼165, and ∼175 kDa proteins were identified as plasmin-sensitive protein (Pls) by mass spectrometry. Previously, Pls has been demonstrated to be a virulence factor in a mouse septic arthritis model. The pls gene is encoded by the staphylococcal cassette chromosome (SCC)mec type I in MRSA that also encodes the methicillin resistance-conferring mecA and further genes. In a search for glycosyltransferases, we identified two open reading frames encoded downstream of pls on the SCCmec element, which we termed gtfC and gtfD. Expression and deletion analysis revealed that both gtfC and gtfD mediate glycosylation of Pls. Additionally, the recently reported glycosyltransferases SdgA and SdgB are involved in Pls glycosylation. Glycosylation occurs at serine residues in the Pls SD-repeat region and modifying carbohydrates are N-acetylhexosaminyl residues. Functional characterization revealed that Pls can confer increased biofilm formation, which seems to involve two distinct mechanisms. The first mechanism depends on glycosylation of the SD-repeat region by GtfC/GtfD and probably also involves eDNA, while the second seems to be independent of glycosylation as well as eDNA and may involve the centrally located G5 domains. Other previously known Pls properties are not related to the sugar modifications. In conclusion, Pls is a glycoprotein and Pls glycosyl residues can stimulate biofilm formation. Thus, sugar modifications may represent promising new targets for novel therapeutic or prophylactic measures against life-threatening S. aureus infections.

【 授权许可】

CC BY