Bacteriophage-encoded virion-associated enzymes to overcome the carbohydrate barriers during the infection process

Abstract

Bacteriophages are bacterial viruses that infect the host after successful receptor recognition and adsorption to the cell surface. The irreversible adherence followed by genome material ejection into host cell cytoplasm must be preceded by the passage of diverse carbohydrate barriers such as capsule polysaccharides (CPSs), O-polysaccharide chains of lipopolysaccharide (LPS) molecules, extracellular polysaccharides (EPSs) forming biofilm matrix, and peptidoglycan (PG) layers. For that purpose, bacteriophages are equipped with various virion-associated carbohydrate active enzymes, termed polysaccharide depolymerases and lysins, that recognize, bind, and degrade the polysaccharide compounds. We discuss the existing diversity in structural locations, variable architectures, enzymatic specificities, and evolutionary aspects of polysaccharide depolymerases and virion-associated lysins (VALs) and illustrate how these aspects can correlate with the host spectrum. In addition, we present methods that can be used for activity determination and the application potential of these enzymes as antibacterials, antivirulence agents, and diagnostic tools.

Keywords: Bacteriophages; Polysaccharide depolymerases; Virion-associated lysins.

Fig. 1

Structural architecture of phage tailspike/depolymerase on the base of P22 tailspike (PDB ID 1LKT and 1TYV; JavaScript Protein Viewer). N-terminal dome-like structure domain (a). Central domain for host recognition and enzymatic activity (b). C-terminal domain responsible for protein trimerization or/and receptor recognition (c)