Structural and genetic characterization of the O-antigen of Salmonella enterica O56 containing a novel derivative of 4-amino-4,6-dideoxy- d-glucose

• Published in: Carbohydrate research 2010-09, Vol.345 (13), p.1891-1895
• Main Authors: Perepelov, Andrei V., Liu, Bin, Shevelev, Sergei D., Senchenkova, Sof’ya N., Hu, Bo, Shashkov, Alexander S., Feng, Lu, Knirel, Yuriy A., Wang, Lei
• Format: Article
• Language: English
• Subjects: 4-Amino-4,6-dideoxy- d-glucose; Bacterial polysaccharide structure; Carbohydrate Sequence; Glucosamine - analogs & derivatives; Glucosamine - chemistry; Molecular Sequence Data; Multigene Family; O Antigens - chemistry; O Antigens - genetics; O-Antigen; O-Antigen gene cluster; Salmonella enterica; Salmonella enterica - chemistry; Salmonella enterica - genetics; Sequence Analysis, DNA
• ISSN: 0008-6215; 1873-426X
• DOI: 10.1016/j.carres.2010.05.007

Based on the O-antigens (O-polysaccharides), one of the most variable cell constituents, 46 O-serogroups have been recognized in the Kauffmann–White serotyping scheme for Salmonella enterica. In this work, the structure of the O-polysaccharide and the genetic organization of the O-antigen gene cluster of S. enterica O56 were investigated. As judged by sugar and methylation analyses, along with NMR spectroscopic data, the O-polysaccharide has a linear tetrasaccharide O-unit, which consists of one residue each of d-ribofuranose, N-acetyl- d-glucosamine, N-acetyl- d-galactosamine, and a novel sugar derivative, 4-( N-acetyl- l-seryl)amino-4,6-dideoxy- d-glucose ( d-Qui4NSerAc). The following structure of the O-polysaccharide was established: →3)-β- d-Qui p4NSerAc-(1→3)-β- d-Rib f-(1→4)-α- d-Gal pNAc-(1→3)-α- d-Glc pNAc-(1→ The O-antigen gene cluster of S. enterica O56 having 12 open reading frames was found between the housekeeping genes galF and gnd. A comparison with databases and using the O-antigen structure data enabled us to ascribe functions to genes for (i) synthesis of d-GalNAc and d-Qui4NSerAc, (ii) sugar transfer, and (iii) O-antigen processing, including genes for O-unit flippase (Wzx) and O-antigen polymerase (Wzy).