Rhodopseudomonas palustris strain CGA009 produces an O-antigen built up by a C-4-branched monosaccharide : structural and conformational studies

Abstract

Here, the analysis of the peculiar homopolymeric O-chain, isolated from the lipopolysaccharide (LPS) of Rhodopseudomonas palustris strain CGA009, is reported. The O-chain is built up of a novel 4-C-branched sugar (12-deoxy-4-C-(D-altro-5,7,8,9-tetrahydroxyhexyl))-3-O-methyl-D-galactopyranose)) whose structure, absolute configuration, and conformational features were deduced by 2D NMR spectroscopy, optical rotation measurements, and molecular dynamics simulations