Presence of N-l-lactyl-d-perosamine residue in the sheath-forming polysaccharide of Thiothrix fructosivorans
Presence of N-l-lactyl-d-perosamine residue in the sheath-forming polysaccharide of Thiothrix fructosivorans
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食果硫丝菌的鞘形成多糖中存在 N-L-乳酰-d-过胺残基
DOI：
10.1016/j.ijbiomac.2015.10.028
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
Minoru Takeda.
中科院分区：
文献类型：
--
作者：
Yuta Kawasaki;Keiko Kondo;Rie Narizuka;Tomoyuki Endo;Masato Katahira;Izuru Kawamura;Michio Sato;Minoru Takeda.
果糖硫刺虫转化成一个微管（鞘），它包裹着一排细胞。该鞘是[→4)- glcn -(1→4)-Glc-(1→]n与侧链Rha4N-(1→3)- fuc（1→）在Glc的3位的组合。成鞘多糖（SFP）可能有一些取代，但尚未得到证实。为了探讨可能的替代，我们用温和的方法制备了鞘。固体核磁共振分析表明存在n取代。鞘层在0℃下用浓盐酸水解，然后用4-氨基苯甲酸乙酯（ABEE）衍生化。核磁共振谱分析表明，n -乳酸- rha4n - fuc - abee的存在。采用手性高效液相色谱法测定乳酸为同分异构体。为了估计n -乙酰化程度，鞘被n -乙酰化。n - acetyl - rha4n - fuce - abee和n -lactyl- rha4n - fuce - abee经核磁共振分析确定丰度比为1:4。在40℃条件下水解，得到GlcNAc-ABEE。用氘化乙酸酐对鞘层进行n -乙酰化，制备n -乙酰gln - abee。根据1D-1H核磁共振光谱中乙酰质子信号的相对强度，确定氘化n -乙酰- glcn - abee的含量为50%。结果表明，Rha4N主要发生n -l-乙酰化，GlcN主要发生n -l-乙酰化。
Thiothrix fructosivoransforms a microtube (sheath) that encloses a line of cells. This sheath is an assemblage of [→4)-GlcN-(1 → 4)-Glc-(1→]nwith side chains of Rha4N-(1 → 3)-Fuc(1→ at position 3 of Glc. The sheath-forming polysaccharide (SFP) may have some substitutions but this is not yet confirmed. To investigate the possible substitutions, the sheath was prepared by mild treatments. Solid-state NMR analysis suggested the presence ofN-substitution. The sheath was hydrolyzed with concentrated HCl at 0 °C, followed by derivatization with 4-aminobenzoic acid ethyl ester (ABEE). The presence ofN-lactyl-Rha4N-Fuc-ABEE was suggested by NMR spectroscopy. Lactic acid was determined to be thel-isomer by chiral HPLC analysis. To estimate theN-lactylation degree, the sheath wasN-acetylated.N-Acetyl-Rha4N-Fuc-ABEE andN-lactyl-Rha4N-Fuc-ABEE were then collectively recovered, and their abundance ratio was determined to be 1:4 by NMR analysis. When hydrolysis was performed at 40 °C, GlcNAc-ABEE was obtained. For estimation of theN-acetylation degree, the sheath wasN-acetylated with deuterated acetic anhydride and thenN-acetyl-GlcN-ABEE was prepared. The content of deuteratedN-acetyl-GlcN-ABEE was determined to be 50% based on the relative intensity of the acetyl proton signal in the 1D-1H NMR spectrum. It was concluded that Rha4N is mostlyN-l-lactylated and GlcN is substoichiometricallyN-acetylated.