Institute of Biochemistry and Physiology of Plants and Microorganisms, Russian Academy of Sciences, 13 Prospekt Entuziastov, Saratov 410049, Russia.
G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch of Russian Academy of Sciences, 159 Prospekt 100 Let Vladivostoku, Vladivostok 690022, Russia.
Int J Biol Macromol. 2020 Oct 15;161:891-897. doi: 10.1016/j.ijbiomac.2020.06.093. Epub 2020 Jun 15.
The lipopolysaccharide (LPS) of Herbaspirillum frisingense GSF30 (HfGSF30), a non-pathogenic diazotrophic endobiont, was isolated by phenol-water extraction from bacterial cells and was characterized by chemical analyses and SDS PAGE. The O-specific polysaccharide (OPS, O-antigen), obtained by mild acid hydrolysis of the LPS, was examined by sugar and methylation analysis, along with H and C NMR spectroscopy, including 2D H,H COSY, H,H TOCSY, H,H ROESY, H,C HSQC, and H,C HMBC experiments. The OPS was found to consist of branched tetrasaccharide repeating units of the following structure: [Formula: see text] This structure is unique among the known bacterial polysaccharide structures. Analysis of the HfGSF30 genome showed that it contained a set of sequentially arranged operons (presumably a cluster of genes) associated with the O-antigen. Amino acid sequence analysis using the BLAST program demonstrated the specificity of this putative cluster for Herbaspirillum spp. The genes responsible for the biosynthesis of the OPS of HfGSF30 were dispersed in the genome, constituting small operons. A putative O-antigen gene cluster of HfGSF30 was identified and found to be consistent with the OPS structure.
植物根瘤菌 GSF30（HfGSF30）的脂多糖（LPS）是一种非致病性固氮内生菌，通过从细菌细胞中用苯酚-水提取分离得到，并通过化学分析和 SDS PAGE 进行了表征。通过 LPS 的温和酸水解获得的 O-特异性多糖（OPS，O-抗原），通过糖和甲基化分析，以及 H 和 C NMR 光谱学，包括 2D H,H COSY、H,H TOCSY、H,H ROESY、H,C HSQC 和 H,C HMBC 实验进行了检查。发现 OPS 由以下结构的支化四糖重复单元组成：[Formula: see text] 这种结构在已知的细菌多糖结构中是独特的。对 HfGSF30 基因组的分析表明，它包含一组与 O-抗原相关的顺序排列的操纵子（推测是一组基因）。使用 BLAST 程序进行的氨基酸序列分析表明，这个假定的簇对 Herbaspirillum spp. 具有特异性。负责 HfGSF30 OPS 生物合成的基因分散在基因组中，构成小的操纵子。鉴定出 HfGSF30 的推定 O-抗原基因簇，并发现与 OPS 结构一致。
