Structures of Capsular Polysaccharide Serotypes 35F and 35C of Streptococcus pneumoniae Determined by Nuclear Magnetic Resonance and Their Relation to Other Cross-Reactive Serotypes----中国科学院微生物研究所

科研成果

论文题目:	Structures of Capsular Polysaccharide Serotypes 35F and 35C of Streptococcus pneumoniae Determined by Nuclear Magnetic Resonance and Their Relation to Other Cross-Reactive Serotypes
作者:	Bush C Allen, Cisar John O, and Yang Jinghua*.
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刊物名称:	J Bacteriol
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年份:	2015
影响因子:	3.11
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摘要:	Structures of Streptococcus pneumoniae capsular polysaccharides (CPS) are essential for defining antigenic as well as genetic relationships between CPS serotypes. The four serotypes that comprise CPS serogroup 35 (i.e. types 35F, 35A, 35B and 35C) are known to cross-react with genetically related types 20, 29, 34, 42 or 47F. While the structures of CPS35A and 35B are known, those of CPS35F and 35C are not. In the present study, the latter two CPS serotypes were characterized by high-resolution hetero-nuclear magnetic resonance (NMR) spectroscopy and glycosyl composition analyses to reveal the following repeat unit structures:CPS35F [-6Galf-(2-OAc)-beta1-3Galalpha1-2Ribitol-5-PO4 --3Galfbeta1-3Galbeta1-]nCPS35C [-6Galfbeta1-1Manitol-6-PO4 --3Galbeta1-3Galfbeta1-3Glcbeta1-]nGlcalpha1/2 Importantly, CPS35F, the immunizing serotype for production of group 35 serum, more closely resembles CPS34 and CPS47F than other members of serogroup 35. Moreover, CPS35C is distinct from either CPS35F or CPS35B but closely related to CPS35A and identical to de-O-acetylated CPS42. The findings provide a comprehensive view of structural and genetic relations that exist between the members of CPS serogroup 35 and other cross reactive serotypes. IMPORTANCE: Cross reactions of diagnostic rabbit antisera with Streptococcus pneumoniae capsular polysaccharides serotypes are generally limited to members of the same serogroup. Exceptions do however occur, most notably among a group of non-vaccine serotypes that includes the members of serogroup 35 (i.e. 35F, 35A, 35B and 35C) and other genetically related types. The presently determined structures of S. pneumoniae serotypes 35F and 35C complete structural characterization of serogroup 35 and thereby provide the first comprehensive description of how different members of this serogroup are related to each other and to types 29, 34, 42 and 47F. The structural and genetic features of these serotypes suggest three distinct capsular polysaccharide subgroups that presumably emerged by immune selection in the human host.