3-Deoxy-D-manno-octulosonic Acid (Kdo) Hydrolase Identified in Francisella tularensis, Helicobacter pylori, and Legionella pneumophila
3-Deoxy-D-manno-octulosonic Acid (Kdo) Hydrolase Identified in Francisella tularensis, Helicobacter pylori, and Legionella pneumophila
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DOI：
10.1074/jbc.m110.166314
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发表时间：
2010-11-05
影响因子：
4.8
通讯作者：
Kasper, Dennis L.
中科院分区：
文献类型：
--
作者：
Chalabaev, Sabina;Kim, Tae-Hyun;Kasper, Dennis L.
3-脱氧-D-甘露-辛酮糖酸（Kdo）是一种普遍存在于革兰氏阴性细菌脂多糖（LPS）中的八碳糖。尽管其生物合成已被充分描述，但尚未鉴定出蛋白质为Kdo水解酶。然而，在幽门螺杆菌和土拉弗朗西斯菌的膜中已经检测到Kdo水解酶的酶活性，并且可能负责从LPS核心酶中去除侧链Kdo。我们现在报道了在F.土拉热菌Schu S4和活疫苗株，在H. pylori 26695菌株和嗜肺军团菌Philadelphia 1菌株。我们将基因kdhA重新命名为酮脱氧辛酮糖酸水解酶A。KdhA基因的缺失使F.土拉热活疫苗株。食品药品管理土拉热菌kdhA突变体合成了含有Kdo二糖的核心寡糖，其中一个Kdo残基是末端侧链。该侧链Kdo单糖在野生型核心寡糖中不存在。重组F. tularensis，H. pylori和L. pneumophila导致膜相关侧链Kdo减少。这种以前不知名的酶的鉴定将加速对生物合成基础和生物合成后LPS结构修饰的生物影响的研究。
3-Deoxy-D-manno-octulosonic acid (Kdo) is an eight-carbon sugar ubiquitous in Gram-negative bacterial lipopolysaccharides (LPS). Although its biosynthesis is well described, no protein has yet been identified as a Kdo hydrolase. However, Kdo hydrolase enzymatic activity has been detected in membranes of Helicobacter pylori and Francisella tularensis and may be responsible for the removal of side-chain Kdo from the LPS core saccharides. We now report the identification of genes encoding a Kdo hydrolase in F. tularensis Schu S4 and live vaccine strain strains, in H. pylori 26695 strain and in Legionella pneumophila Philadelphia 1 strain. We have renamed the genes kdhA for keto-deoxyoctulosonate hydrolase A. Deletion of kdhA abolished Kdo hydrolase activity in membranes of F. tularensis live vaccine strain. The F. tularensis kdhA mutant synthesized a core oligosaccharide containing a Kdo disaccharide with one of the Kdo residues being a terminal side chain. This side-chain Kdo monosaccharide was absent in the wild-type core oligosaccharide. Expression in Escherichia coli of recombinant KdhA from F. tularensis, H. pylori, and L. pneumophila resulted in a reduction of membrane-associated side-chain Kdo. The identification of this previously faceless enzyme will accelerate study of the biosynthetic basis and biologic impact for postbiosynthetic LPS structural modification.