Structural basis for the substrate specificity of a novel β-N-acetylhexosaminidase StrH protein from Streptococcus pneumoniae R6.

ABSTRACT: The β-N-acetylhexosaminidase (EC 3.2.1.52) from glycoside hydrolase family 20 (GH20) catalyzes the hydrolysis of the β-N-acetylglucosamine (NAG) group from the nonreducing end of various glycoconjugates. The putative surface-exposed N-acetylhexosaminidase StrH/Spr0057 from Streptococcus pneumoniae R6 was proved to contribute to the virulence by removal of β(1,2)-linked NAG on host defense molecules following the cleavage of sialic acid and galactose by neuraminidase and β-galactosidase, respectively. StrH is the only reported GH20 enzyme that contains a tandem repeat of two 53% sequence-identical catalytic domains (designated as GH20-1 and GH20-2, respectively). Here, we present the 2.1 Å crystal structure of the N-terminal domain of StrH (residues Glu-175 to Lys-642) complexed with NAG. I

SUBMITTER: Jiang YL 

PROVIDER: S-EPMC3234876 | biostudies-literature | 2011 Dec

REPOSITORIES: biostudies-literature