Midwest Center for Structural Genomics and Structural Biology Center, Biosciences, Argonne National Laboratory, 9700 South Cass Avenue, Building 202, Argonne, IL 60439, USA.
J Mol Biol. 2011 Feb 18;406(2):325-42. doi: 10.1016/j.jmb.2010.12.021. Epub 2010 Dec 23.
The main pathway of bacterial sugar phosphorylation utilizes specific phosphoenolpyruvate phosphotransferase system (PTS) enzymes. In addition to the classic PTS system, a PTS-independent secondary system has been described in which nucleotide-dependent sugar kinases are used for monosaccharide phosphorylation. Fructokinase (FK), which phosphorylates d-fructose with ATP as a cofactor, has been shown to be a member of this secondary system. Bioinformatic analysis has shown that FK is a member of the "ROK" (bacterial Repressors, uncharacterized Open reading frames, and sugar Kinases) sequence family. In this study, we report the crystal structures of ROK FK from Bacillus subtilis (YdhR) (a) apo and in the presence of (b) ADP and (c) ADP/d-fructose. All structures show that YdhR is a homodimer with a monomer composed of two similar α/β domains forming a large cleft between domains that bind ADP and D-fructose. Enzymatic activity assays support YdhR function as an ATP-dependent fructose kinase.
细菌糖磷酸化的主要途径利用特定的磷酸烯醇丙酮酸磷酸转移酶系统（PTS）酶。除了经典的 PTS 系统外，还描述了一种 PTS 独立的次要系统，其中核苷酸依赖性糖激酶用于单糖磷酸化。已经表明，与 ATP 作为辅助因子磷酸化 d-果糖的果糖激酶（FK）是该次要系统的成员。生物信息学分析表明，FK 是“ROK”（细菌阻遏物、未表征的开放阅读框和糖激酶）序列家族的成员。在这项研究中，我们报告了枯草芽孢杆菌（YdhR）的 ROK FK 的晶体结构（a）apo 和（b）ADP 和（c）ADP/d-果糖的存在。所有结构都表明，YdhR 是一个同源二聚体，单体由两个相似的α/β结构域组成，在结构域之间形成一个大的裂隙，该裂隙结合 ADP 和 D-果糖。酶活性测定支持 YdhR 作为 ATP 依赖性果糖激酶的功能。
