Caines Matthew E C, Zhu Haizhong, Vuckovic Marija, Willis Lisa M, Withers Stephen G, Wakarchuk Warren W, Strynadka Natalie C J
Department of Biochemistry and Molecular Biology, Centre for Blood Research and Department of Chemistry, University of British Columbia, Vancouver, British Columbia, V6T 1Z3.
J Biol Chem. 2008 Nov 14;283(46):31279-83. doi: 10.1074/jbc.C800150200. Epub 2008 Sep 10.
Streptococcus pneumoniae endo-alpha-N-acetylgalactosaminidase is a cell surface-anchored glycoside hydrolase from family GH101 involved in the breakdown of mucin type O-linked glycans. The 189-kDa mature enzyme specifically hydrolyzes the T-antigen disaccharide from extracellular host glycoproteins and is representative of a broadly important class of virulence factors that have remained structurally uncharacterized due to their large size and highly modular nature. Here we report a 2.9 angstroms resolution crystal structure that remarkably captures the multidomain architecture and characterizes a catalytic center unexpectedly resembling that of alpha-amylases. Our analysis presents a complete model of glycoprotein recognition and provides a basis for the structure-based design of novel Streptococcus vaccines and therapeutics.
肺炎链球菌内切α-N-乙酰半乳糖胺酶是一种来自GH101家族的细胞表面锚定糖苷水解酶,参与粘蛋白O-连接聚糖的分解。这种189 kDa的成熟酶能特异性地从细胞外宿主糖蛋白中水解T抗原二糖,是一类广泛重要的毒力因子的代表,由于其体积大且结构高度模块化,其结构仍未得到表征。在此,我们报告了一个分辨率为2.9埃的晶体结构,该结构显著捕捉到了多结构域架构,并表征了一个意外类似于α-淀粉酶的催化中心。我们的分析提出了一个完整的糖蛋白识别模型,并为新型肺炎链球菌疫苗和治疗药物的基于结构的设计提供了基础。