Functional characterization of the endolysins derived from mycobacteriophage PDRPxv

In this study, we report the structural and functional characterization of endolysins (LysinA and LysinB) encoded by mycobacteriophage PDRPxv which belongs to B1 sub cluster. On in silico analysis, we found LysinA to be a modular protein having peptidase domain at the N-terminal (104 aa), a central amidase domain (174 aa) and  the peptidoglycan binding domain (62 aa) at the C-terminal. Additionally, ‘H-X-H’, which is a conserved motif and characteristic of peptidase domains, and the conserved residues His-His-Asp, which are characteristic of amidase domain were also observed. In LysinB enzyme, a single α/β hydrola se domain having a catalytic triad (Ser-Asp-His) and G-X-S-X-G motif, which are characteristic of the serine esterase enzymes were predicted to be present. Both the enzymes were purified as recombinant proteins and their antimycobacterial activity againstM. smegmatis was demonstrated through turbidimetric experiments and biochemical assay. Interesting observation in this study is the secretory nature of LysinA evident by its periplasmic expression  inE.coli, which might explain the ability of PDRPxv to lyse the bacterial host in the absence of transmembrane Holin protein.
Source: World Journal of Microbiology and Biotechnology - Category: Microbiology Source Type: research