The Bacterial Defensin Resistance Protein MprF Consists of Separable Domains for Lipid Lysinylation and Antimicrobial Peptide Repulsion

PLoS Pathogens

Petra Staubitz¹  Gabriele Hornig¹  Christoph M. Ernst¹  Andreas Peschel¹  Dirk Kraus²  Nagendra N. Mishra³  Soo-Jin Yang³  Arnold S. Bayer³  Hubert Kalbacher⁴ 

[1] Cellular and Molecular Microbiology Division, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany;David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America;Division of Infectious Diseases, Los Angeles Biomedical Research Institute at Harbor–University of California at Los Angeles (UCLA) Medical Center, Torrance, California, United States of America;Medical and Natural Sciences Research Center, University of Tübingen, Tübingen, Germany

关键词: Staphylococcus aureus;    Protein domains;    Lipids;    Antimicrobial resistance;    Bacterial pathogens;    Plasmid construction;    Biosynthesis;    Antimicrobials;   

DOI  :  10.1371/journal.ppat.1000660

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Many bacterial pathogens achieve resistance to defensin-like cationic antimicrobial peptides (CAMPs) by the multiple peptide resistance factor (MprF) protein. MprF plays a crucial role in Staphylococcus aureus virulence and it is involved in resistance to the CAMP-like antibiotic daptomycin. MprF is a large membrane protein that modifies the anionic phospholipid phosphatidylglycerol with l-lysine, thereby diminishing the bacterial affinity for CAMPs. Its widespread occurrence recommends MprF as a target for novel antimicrobials, although the mode of action of MprF has remained incompletely understood. We demonstrate that the hydrophilic C-terminal domain and six of the fourteen proposed trans-membrane segments of MprF are sufficient for full-level lysyl-phosphatidylglycerol (Lys-PG) production and that several conserved amino acid positions in MprF are indispensable for Lys-PG production. Notably, Lys-PG production did not lead to efficient CAMP resistance and most of the Lys-PG remained in the inner leaflet of the cytoplasmic membrane when the large N-terminal hydrophobic domain of MprF was absent, indicating a crucial role of this protein part. The N-terminal domain alone did not confer CAMP resistance or repulsion of the cationic test protein cytochrome c. However, when the N-terminal domain was coexpressed with the Lys-PG synthase domain either in one protein or as two separate proteins, full-level CAMP resistance was achieved. Moreover, only coexpression of the two domains led to efficient Lys-PG translocation to the outer leaflet of the membrane and to full-level cytochrome c repulsion, indicating that the N-terminal domain facilitates the flipping of Lys-PG. Thus, MprF represents a new class of lipid-biosynthetic enzymes with two separable functional domains that synthesize Lys-PG and facilitate Lys-PG translocation. Our study unravels crucial details on the molecular basis of an important bacterial immune evasion mechanism and it may help to employ MprF as a target for new anti-virulence drugs.

【 授权许可】

CC BY