Turska-Szewczuk Anna, Duda Katarzyna A, Schwudke Dominik, Pekala Agnieszka, Kozinska Alicja, Holst Otto
Department of Genetics and Microbiology, M. Curie-Sklodowska University, Akademicka 19, Lublin 20-033, Poland.
Division of Structural Biochemistry, Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Parkallee 4a/c, Borstel D-23845, Germany.
Mar Drugs. 2014 Mar 7;12(3):1298-316. doi: 10.3390/md12031298.
Chemical analyses, mass spectrometry, and NMR spectroscopy were applied to study the structure of the lipopolysaccharide (LPS) isolated from Aeromonas veronii strain Bs19, serotype O16. ESI-MS revealed that the most abundant LPS glycoforms have tetra-acylated or hexa-acylated lipid A species, consisting of a bisphosphorylated GlcN disaccharide with an AraN residue as a non-stoichiometric substituent, and a core oligosaccharide composed of Hep₅Hex₃HexN₁Kdo₁P₁. Sugar and methylation analysis together with 1D and 2D ¹H and ¹³C NMR spectroscopy were the main methods used, and revealed that the O-specific polysaccharide (OPS) of A. veronii Bs19 was built up of tetrasaccharide repeating units with the structure: →4)-α-D-Quip3NAc-(1→3)-α-L-Rhap-(1→4)-β-D-Galp-(1→3)-α-D-GalpNAc-(1→. This composition was confirmed by mass spectrometry. The charge-deconvoluted ESI FT-ICR MS recorded for the LPS preparations identified mass peaks of SR- and R-form LPS species, that differed by Δm = 698.27 u, a value corresponding to the calculated molecular mass of one OPS repeating unit (6dHexNAc6dHexHexHexNAc-H₂O). Moreover, unspecific fragmentation spectra confirmed the sequence of the sugar residues in the OPS and allowed to assume that the elucidated structure also represented the biological repeating unit.
采用化学分析、质谱和核磁共振光谱法研究了从维氏气单胞菌Bs19菌株（血清型O16）中分离出的脂多糖（LPS）的结构。电喷雾电离质谱（ESI-MS）显示，最丰富的LPS糖型具有四酰化或六酰化的类脂A种类，由带有一个作为非化学计量取代基的阿拉伯糖胺（AraN）残基的双磷酸化葡糖胺（GlcN）二糖组成，以及一个由5个庚糖（Hep）、3个己糖（Hex）、1个己糖胺（HexN）和1个3-脱氧-D-甘露糖型庚糖酸（Kdo）组成的核心寡糖。糖和甲基化分析以及一维和二维¹H和¹³C核磁共振光谱是主要使用的方法，结果表明维氏气单胞菌Bs19的O-特异性多糖（OPS）由具有以下结构的四糖重复单元组成：→4)-α-D-喹诺糖胺-3-乙酸酯-(1→3)-α-L-鼠李糖-(1→4)-β-D-半乳糖-(1→3)-α-D-半乳糖胺-(1→。该组成通过质谱得到了证实。对LPS制剂记录的电荷去卷积电喷雾电离傅里叶变换离子回旋共振质谱（ESI FT-ICR MS）鉴定出了SR型和R型LPS种类的质量峰，它们相差Δm = 698.27 u，该值对应于一个OPS重复单元的计算分子量（6个脱氧己糖胺、6个脱氧己糖、己糖、己糖、己糖胺 - H₂O）。此外，非特异性碎片光谱证实了OPS中糖残基的序列，并使得可以假定所阐明的结构也代表生物学重复单元。
