Identification and characterization of the antigonococcal prophage-encoded endolysin Phi1gp518

Abstract

Gonorrhea, caused by the Gram-negative bacterium Neisseria gonorrhoeae, poses a growing global public health threat due to the rapid emergence of multidrug-resistant strains and the limited availability of effective treatments. Since there are no known lytic gonophages, we explored prophages present in the genome of N. gonorrhoeae FA1090, with a particular focus on prophage-encoded endolysins. In this study, we evaluate antigonococcal properties of prophage-encoded endopeptidases with the NlpC/P60 enzymatic domain. Recombinant endolysin Phi1gp518 exhibits intrinsic bactericidal activity against non-permeabilized N. gonorrhoeae FA1090 cells. Furthermore, it shows an expanded host range against clinical gonococcal isolates. The gonolysin remains stable across all human body temperatures, a pH range of 5-10, and shows no cytotoxic effects toward human cervical epithelial cells, supporting its potential safety for therapeutic applications. Additionally, Phi1gp518 impairs the formation of gonococcal microcolonies and prevents proper biofilm establishment. The antigonococcal properties of Phi1gp518 endopeptidase make it a good candidate for further protein engineering and development as an alternative treatment strategy for drug-resistant N. gonorrhoeae infections.