Klebsiella pneumoniae K2 capsular polysaccharide degradation by a bacteriophage depolymerase does not require trimer formation.

ABSTRACT: K2-capsular Klebsiella pneumoniae is a hypervirulent pathogen that causes fatal infections. Here, we describe a phage tailspike protein, named K2-2, that specifically depolymerizes the K2 capsular polysaccharide (CPS) of K. pneumoniae into tetrasaccharide repeating units. Nearly half of the products contained O-acetylation, which was thought crucial to the immunogenicity of CPS. The product-bound structures of this trimeric enzyme revealed intersubunit carbohydrate-binding grooves, each accommodating three tetrasaccharide units of K2 CPS. The catalytic residues and the key interactions responsible for K2 CPS recognition were identified and verified by site-directed mutagenesis. Further biophysical and functional characterization, along with the structure of a tetrameri

SUBMITTER: Ye T-J 

PROVIDER: S-EPMC10936425 | biostudies-literature | 2024 Mar

REPOSITORIES: biostudies-literature