INRA, UMR1319 Microbiologie de l'Alimentation au Service de la Santé Humaine, Jouy en Josas, France.
J Bacteriol. 2012 Sep;194(18):4972-82. doi: 10.1128/JB.00801-12. Epub 2012 Jul 6.
Several bacteria use glycerol dehydrogenase to transform glycerol into dihydroxyacetone (Dha). Dha is subsequently converted into Dha phosphate (Dha-P) by an ATP- or phosphoenolpyruvate (PEP)-dependent Dha kinase. Listeria innocua possesses two potential PEP-dependent Dha kinases. One is encoded by 3 of the 11 genes forming the glycerol (gol) operon. This operon also contains golD (lin0362), which codes for a new type of Dha-forming NAD(+)-dependent glycerol dehydrogenase. The subsequent metabolism of Dha requires its phosphorylation via the PEP:sugar phosphotransferase system components enzyme I, HPr, and EIIA(Dha)-2 (Lin0369). P∼EIIA(Dha)-2 transfers its phosphoryl group to DhaL-2, which phosphorylates Dha bound to DhaK-2. The resulting Dha-P is probably metabolized mainly via the pentose phosphate pathway, because two genes of the gol operon encode proteins resembling transketolases and transaldolases. In addition, purified Lin0363 and Lin0364 exhibit ribose-5-P isomerase (RipB) and triosephosphate isomerase activities, respectively. The latter enzyme converts part of the Dha-P into glyceraldehyde-3-P, which, together with Dha-P, is metabolized via gluconeogenesis to form fructose-6-P. Together with another glyceraldehyde-3-P molecule, the transketolase transforms fructose-6-P into intermediates of the pentose phosphate pathway. The gol operon is preceded by golR, transcribed in the opposite orientation and encoding a DeoR-type repressor. Its inactivation causes the constitutive but glucose-repressible expression of the entire gol operon, including the last gene, encoding a pediocin immunity-like (PedB-like) protein. Its elevated level of synthesis in the golR mutant causes slightly increased immunity against pediocin PA-1 compared to the wild-type strain or a pedB-like deletion mutant.
几种细菌使用甘油脱氢酶将甘油转化为二羟丙酮（Dha）。Dha 随后被依赖 ATP 或磷酸烯醇丙酮酸（PEP）的 Dha 激酶转化为 Dha 磷酸（Dha-P）。无害李斯特菌拥有两种潜在的 PEP 依赖的 Dha 激酶。一种由形成甘油（gol）操纵子的 11 个基因中的 3 个编码。该操纵子还包含 golD（lin0362），它编码一种新型的形成 NAD（+）依赖的甘油脱氢酶的 Dha。Dha 的后续代谢需要通过 PEP：糖磷酸转移酶系统成分酶 I、HPr 和 EIIA（Dha）-2（Lin0369）对其进行磷酸化。P∼EIIA（Dha）-2 将其磷酸基团转移到 DhaL-2，DhaL-2 将与 DhaK-2 结合的 Dha 磷酸化。所得的 Dha-P 可能主要通过戊糖磷酸途径代谢，因为 gol 操纵子的两个基因编码类似于转酮醇酶和转醛醇酶的蛋白质。此外，纯化的 Lin0363 和 Lin0364 分别表现出核酮糖-5-P 异构酶（RipB）和磷酸丙糖异构酶活性。后一种酶将部分 Dha-P 转化为甘油醛-3-P，与 Dha-P 一起，通过糖异生代谢形成果糖-6-P。与另一个甘油醛-3-P 分子一起，转酮醇酶将果糖-6-P 转化为戊糖磷酸途径的中间产物。gol 操纵子之前是 golR，转录方向相反，编码一种 DeoR 型阻遏物。其失活导致整个 gol 操纵子的组成型但葡萄糖抑制表达，包括编码 pediocin 免疫样（PedB-like）蛋白的最后一个基因。golR 突变体中其合成水平的升高导致与野生型菌株或 pedB-like 缺失突变体相比，对肠球菌素 PA-1 的免疫力略有增加。
