Acinetobacter baumannii K13 and K73 capsular polysaccharides differ only in K-unit side branches of novel non-2-ulosonic acids: di-N-acetylated forms of either acinetaminic acid or 8-epiacinetaminic acid. (27th November 2017)

• Record Type: Journal Article
• Authors: Kenyon, Johanna J.; Kasimova, Anastasiya A.; Notaro, Anna; Arbatsky, Nikolay P.; Speciale, Immacolata; Shashkov, Alexander S.; De Castro, Cristina; Hall, Ruth M.; Knirel, Yuriy A.
• Is Part Of: Carbohydrate research. Volume 452(2017)
• Page Start: 149
• Page End: 155
• Publication Date: 2017-11-27
• Subjects: Acinetobacter baumannii -- Capsular polysaccharide structure -- Capsule biosynthesis gene cluster -- Non-2-ulosonic acid -- 5, 7-Di-N-acetylacinetaminic acid -- 5, 7-Di-N-acetyl-8-epiacinetaminic acid; Carbohydrates -- Periodicals; Chemistry, Organic -- Periodicals; Biochemistry -- Periodicals; Carbohydrates -- Periodicals; Chimie organique -- Périodiques; Glucides -- Périodiques; Biochemistry; Carbohydrates; Chemistry, Organic; Periodicals; Electronic journals; 507.78
• DOI: 10.1016/j.carres.2017.10.005
• Languages: English
• ISSNs: 0008-6215

Abstract

Abstract: Structures of capsular polysaccharides of Acinetobacter baumannii isolates carrying KL13 and KL73 gene clusters were established. The closely related KL73 and KL13 gene clusters differ only by one gene in the module responsible for synthesis of the non-2-ulosonic acids. The K13 and K73 polysaccharides differ only in a single side-chain sugar, which is either 5, 7-diacetamido-3, 5, 7, 9-tetradeoxy-l - glycero -l - altro - or -d - glycero -l - altro -non-2-ulosonic acid [di-N-acetylated forms of acinetaminic acid (Aci5Ac7Ac) or 8-epiacinetaminic acid (8eAci5Ac7Ac), respectively]. The KL13 also is closely related to the KL12 gene cluster, which contains a different wzy gene encoding the K unit polymerase. Accordingly, the otherwise near identical K units are linked differently via an α-d -Fuc p NAc-(1 → 4)-d -Gal p linkage in K13 and K73 or an α-d -Fuc p NAc-(1 → 3)-d -Gal p NAc linkage in K12. This finding confirms the predicted substrate of the ItrB3 initiating transferase asd -Fuc p NAc. Glycosyltransferases predicted to catalyse the linkage ofd -Gal p ord -Gal p NAc tol -Fuc p NAc in the growing K13 and K73 or K12 units, respectively, differ by only two amino acids. Graphical abstract: Highlights: Capsule structures were obtained for Acinetobacter baumannii clinical isolates carrying KL13 and KL73. Capsule repeating units are similar, differing only in the presence of a rare non-2-ulosonic acid. K13 includes Aci5Ac7Ac and K73 includes 8eAci5Ac7Ac. The function of the Wzy polymerases and ItrB3 initiating transferase were unambiguously assigned.