Complete chemical structure of the K135 capsular polysaccharide produced by Acinetobacter baumannii RES-546 that contains 5, 7-di-N-acetyl-8-epipseudaminic acid. (January 2023)

• Record Type: Journal Article
• Authors: Shashkov, Alexander S.; Kasimova, Anastasiya A.; Arbatsky, Nikolay P.; Senchenkova, Sof'ya N.; Perepelov, Andrei V.; Dmitrenok, Andrei S.; Chizhov, Alexander O.; Knirel, Yuriy A.; Shneider, Mikhail M.; Popova, Anastasia V.; Kenyon, Johanna J.
• Is Part Of: Carbohydrate research. Volume 523(2023)
• Publication Date: 2023-01
• Subjects: Acinetobacter baumannii -- Capsular polysaccharide -- 5, 7-Diacetamido-3, 5, 7, 9-tetradeoxynon-2-ulosonic acid -- K135; 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.2022.108726
• Languages: English
• ISSNs: 0008-6215

Abstract

Abstract: A structurally diverse capsular polysaccharide (CPS) in the outer cell envelope plays an important role in the virulence of the important bacterial pathogen, Acinetobacter baumannii . More than 75 different CPS structures have been determined for the species to date, and many CPSs include isomers of a higher sugar, namely 5, 7-diamino-3, 5, 7, 9-tetradeoxynon-2-ulosonic acid. Recently, a novel isomer having the d - glycero -l - manno configuration (5, 7-di- N -acetyl-8-epipseudaminic acid; 8ePse5Ac7Ac) has been identified in the CPS from A. baumannii clinical isolate RES-546 [ Carbohydr. Res. 513 (2022) 108, 531]. Here, the complete chemical structure of this CPS, designated K135, was elucidated. The CPS was found to have a branched tetrasaccharide K unit and to include the higher sugar as part of a 8ePse5Ac7Ac-(2 → 6)-α-Gal disaccharide branching from a →3)-α-D-Glc p NAc-(1 → 3)-β-D-Glc p NAc-(1→ main chain. Assignment of glycosyltransferases encoded by the CPS biosynthesis gene cluster in the RES-546 genome enabled the first sugar of the K unit, and hence the topology of the K135 CPS, to be determined. Graphical abstract: Image 1 Highlights: Complete structure of Acinetobacter baumannii K135 solved. Annotations for the KL135 gene cluster reported. Genes for 8Pse5Ac7Ac were not found at the K locus.