Structure of K102 Capsular Polysaccharide from KZ-1102 and Its Cleavage by Phage Cato Depolymerase.

is a significant nosocomial pathogen characterized by the ability to produce a wide variety of capsular polysaccharides (CPSs). The structures of a K102-type CPS isolated from KZ-1102 and its Smith degradation product were determined by sugar analysis, 1D and 2D H NMR spectroscopy, and C NMR spectroscopy. The K102 CPS biosynthesis gene cluster (KL102) contains genes for common sugar synthesis, K unit processing, capsule export, glycosyl transfer, initiating sugar phosphate transfer, and genes that encode d-GlcNAc/d-GalNAc dehydrogenase and phosphoglycerol transferase. The CPS is composed of a pentasaccharide repeating unit (K unit) consisting of a tetrasaccharide backbone including one α-d-Gal, three α-d-GlcNAc residues, and one residue of a β-d-Glc as a side chain. The tailspike depolymerase of the specific phage Cato was found to cleave the α-d-GlcNAc-(1→6)-α-d-GlcNAc linkage in the K102 CPS to give the monomer and dimer of the K repeating unit, which were characterized by high-resolution electrospray ionization mass spectrometry as well as H and C NMR spectroscopy.