Department of Biotechnology, Division of Advance Science and Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan.
Department of Applied Environmental Biology, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka, 565-0871, Japan.
Chembiochem. 2019 Dec 2;20(23):2961-2967. doi: 10.1002/cbic.201900303. Epub 2019 Aug 22.
Polyphosphate kinase 2 (PPK2) transfer phosphate from inorganic polyphosphate to nucleotides. According to their activity, PPK2 enzymes are classified into three groups. Among them, class III enzymes catalyze both the phosphorylation of nucleotide mono- to diphosphates and di- to triphosphates by using polyphosphate, which is a very inexpensive substrate. Therefore, class III enzymes are very attractive for use in biotechnological applications. Despite several studies on class III enzymes, a detailed mechanism of how phosphate is transferred from the polyphosphate to the nucleotide remains to be elucidated. Herein, it is reported that PPK2 class III enzymes from two different bacterial species catalyze the phosphorylation of adenosine mono- (AMP) into triphosphate (ATP) not only through step-by-step phosphorylation, but also by pyrophosphorylation. These are the first PPK2 enzymes that have been shown to possess polyphosphate-dependent pyrophosphorylation activity.
多聚磷酸激酶 2（PPK2）将磷酸基团从无机多聚磷酸盐转移到核苷酸上。根据其活性，PPK2 酶可分为三组。其中，III 类酶可利用多聚磷酸盐同时催化核苷酸单二磷酸和二磷酸三磷酸的磷酸化，多聚磷酸盐是一种非常廉价的底物。因此，III 类酶在生物技术应用中非常有吸引力。尽管已经对 III 类酶进行了多项研究，但磷酸基团从多聚磷酸盐转移到核苷酸的详细机制仍有待阐明。本文报道了来自两种不同细菌的 PPK2 类 III 酶不仅通过逐步磷酸化，而且通过焦磷酸化催化腺苷单磷酸（AMP）磷酸化为三磷酸（ATP）。这些是首次被证明具有多聚磷酸盐依赖的焦磷酸化活性的 PPK2 酶。
