The Crystal Structure of the Bacteriophage PSA Endolysin Reveals a Unique Fold Responsible for Specific Recognition of Listeria Cell Walls

摘要: Bacteriophage murein hydrolases exhibit high specificity towards the cell walls of their host bacteria. This is mostly provided by a structurally well defined wall-binding domain that attaches enzyme to its solid substrate. To gain deeper insight into this mechanism we have crystallized complete 314 amino acid endolysin from temperate Listeria monocytogenes phage PSA. The crystal structure PlyPSA was determined single wavelength anomalous dispersion methods and refined 1.8 A resolution. two functional domains polypeptide, providing enzymatic activities, can be clearly distinguished are connected via linker segment six residues. core N-acetylmuramoyl-L-alanine amidase moiety formed twisted, six-stranded beta-sheet flanked helices. Although catalytic unique among known endolysins, highly similar phosphorylase/hydrolase-like alpha/beta-proteins, including an autolysin Paenibacillus polymyxa. In contrast, C-terminal features novel fold, comprising copies beta-barrel-like motif, which held together means swapped beta-strands. architecture with separate explains substrate recognition properties also provides lytic mechanisms related class enzymes bear biotechnological potential.