Endolysins—enzymes produced by tailed bacteriophages to degrade bacterial cell walls—have traditionally been classified as canonical or signal-anchor-release (SAR) endolysins. However, expanding viral (meta)genomic data analysis has revealed a third class, which we designate as C-terminal anchor (CTA) endolysins. These enzymes feature an N-terminal enzymatic domain and a C-terminal transmembrane domain, and they typically lack signal sequences, which distinguishes them from SAR endolysins. CTA endolysins span all known enzymatic activities and exhibit diverse architectures, though most have a single transmembrane helix and an N-out, C-in topology, consistent with periplasmic activity. While their functional mechanisms remain to be elucidated, our findings suggest that CTA endolysins are nearly as prevalent as SAR endolysins and represent a distinct, previously unrecognised branch of the endolysin world.
Read here: C-terminal anchor endolysins—proposing a third class of tailed bacteriophage endolysins
PHAGElogist 