A bacteriophage endolysin that eliminates intracellular streptococci

作者：Shen Yang; Barros Marilia; Vennemann Tarek; Ggallagher D Travis; Yin Yizhou; Linden Sara B; Heselpoth Ryan D; Spencer Dennis J; Donovan David M; Moult John; Fischetti Vincent A; Heinrich Frank; Losche Mathias; Nelson Daniel C^*

来源：eLife, 2016, 5: e13152.

DOI：10.7554/eLife.13152

PIyC, a bacteriophage-encoded endolysin, lyses Streptococcus pyogenes (Spy) on contact. Here, we demonstrate that PIyC is a potent agent for controlling intracellular Spy that often underlies refractory infections. We show that the PIyC holoenzyme, mediated by its PIyCB subunit, crosses epithelial cell membranes and clears intracellular Spy in a dose-dependent manner. Quantitative studies using model membranes establish that PIyCB interacts strongly with phosphatidylserine (PS), whereas its interaction with other lipids is weak, suggesting specificity for PS as its cellular receptor. Neutron reflection further substantiates that PIyC penetrates bilayers above a PS threshold concentration. Crystallography and docking studies identify key residues that mediate PIyCB PS interactions, which are validated by site-directed mutagenesis. This is the first report that a native endolysin can traverse epithelial membranes, thus substantiating the potential of PIyC as an antimicrobial for Spy in the extracellular and intracellular milieu and as a scaffold for engineering other functionalities.

• 出版日期2016-3-15