Arbatsky Nikolay P, Kasimova Anastasiya A, Shashkov Alexander S, Shneider Mikhail M, Popova Anastasiya V, Perepelov Andrey V, Hall Ruth M, Kenyon Johanna J, Knirel Yuriy A
N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia.
M. M. Shemyakin and Y. A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 119997, Moscow, Russia.
Carbohydr Res. 2024 Jan;535:109020. doi: 10.1016/j.carres.2023.109020. Epub 2023 Dec 21.
K63 capsular polysaccharide produced by Acinetobacter baumannii isolate LUH5551 (previously designated isolate O24) was re-examined using sugar analysis, Smith degradation, and one- and two-dimensional H and C NMR spectroscopy. Though previously reported as O24 consisting of linear tetrasaccharide units that include a 7-acetamido-5-acylamino form of 8-epilegionaminic acid [8eLeg5R7Ac, acylated at C5 with (S)-3-hydroxybutanoyl or acetyl (1:1)], the elucidated structure of the K63 type capsule was found to include a derivative of 5,7-diamino-3,5,7,9-tetradeoxy-d-glycero-d-galacto-non-2-ulosonic (legionaminic) acid, Leg5Ac7R, where R is either (S)-3-hydroxybutanoyl or an acetyl group (∼1:1 ratio). This finding is consistent with the presence of the lgaABCHIFG gene module for Leg5Ac7R biosynthesis in the KL63 gene cluster at the capsular polysaccharide (CPS) biosynthesis K locus in the LUH5551 genome. The glycosyltransferases (Gtrs) and Wzy polymerase encoded by KL63 were assigned to linkages in the linear K63 tetrasaccharide unit and linkage of the K63 units.
利用糖分析、史密斯降解以及一维和二维氢碳核磁共振光谱法，对鲍曼不动杆菌分离株LUH5551（先前命名为分离株O24）产生的K63荚膜多糖进行了重新研究。尽管先前报道O24由线性四糖单元组成，其中包括8-表军团氨糖酸的7-乙酰氨基-5-酰氨基形式[8eLeg5R7Ac，在C5处被（S）-3-羟基丁酰基或乙酰基酰化（1:1）]，但发现K63型荚膜的阐明结构包括5,7-二氨基-3,5,7,9-四脱氧-D-甘油-D-半乳糖-壬-2-酮糖酸（军团氨糖酸）的衍生物Leg5Ac7R，其中R为（S）-3-羟基丁酰基或乙酰基（比例约为1:1）。这一发现与LUH5551基因组中荚膜多糖（CPS）生物合成K位点的KL63基因簇中存在用于Leg5Ac7R生物合成的lgaABCHIFG基因模块一致。由KL63编码的糖基转移酶（Gtrs）和Wzy聚合酶被指定负责线性K63四糖单元中的连接以及K63单元的连接。
