Redirecting Pore Assembly of Staphylococcal ?-Hemolysin by Protein Engineering.

ABSTRACT: ?-Hemolysin (?HL), a ?-barrel pore-forming toxin (?PFT), is secreted as a water-soluble monomer by Staphylococcus aureus. Upon binding to receptors on target cell membranes, ?HL assembles to form heptameric membrane-spanning pores. We have previously engineered ?HL to create a protease-activatable toxin that is activated by site-specific proteolysis including by tumor proteases. In this study, we redesigned ?HL so that it requires 2-fold activation on target cells through (i) binding to specific receptors, and (ii) extracellular proteolytic cleavage. To assess our strategy, we constructed a fusion protein of ?HL with galectin-1 (?HLG1, ?HL-Galectin-1 chimera). ?HLG1 was cytolytic toward cells that lack a receptor for wild-type ?HL. We then constructed protease-activatable mutants of ?HLG1 (PAM?HLG1s). PAM?HLG1s were activated by matrix metalloproteinase 2 (MMP-2) and had approximately 50-fold higher cytolytic activity toward MMP-2 overexpressing cells (HT-1080 cells) than toward non-overexpressing cells (HL-60 cells). Our approach provides a novel strategy for tailoring pore-forming toxins for therapeutic applications.

SUBMITTER: Koo S 

PROVIDER: S-EPMC6487460 | biostudies-literature | 2019 Apr

REPOSITORIES: biostudies-literature