Abstract
The studies of 3-deoxy-d-manno-octulosonic acid (KDO) have been hindered due to its limited availability. Herein, an efficient enzymatic system for the facile synthesis of KDO from easy-to-get starting materials is described. In this one-pot three-enzyme (OPME) system, d-ribulose 5-phosphate, which was prepared from d-xylose, was employed as starting materials. The reaction process involves the isomerization of d-ribulose 5-phosphate to d-arabinose 5-phosphate catalyzed by d-arabinose 5-phosphate isomerase (KdsD), the aldol condensation of d-arabinose 5-phosphate and phosphoenolpyruvate (PEP) catalyzed by KDO 8-phosphate synthetase (KdsA), and the hydrolysis of KDO-8-phosphate catalyzed by KDO 8-phosphate phosphatase (KdsC). By using this OPME system, 72% isolated yield was obtained. The obtained KDO was further transferred to lipid A by KDO transferase from Escherichia coli (WaaA).