College of Life Sciences, Nankai University, Tianjin, China.
College of Life Sciences, Nankai University, Tianjin, China.
Biochem Biophys Res Commun. 2018 Jun 7;500(3):804-809. doi: 10.1016/j.bbrc.2018.04.163. Epub 2018 Apr 24.
The C5 pathway in bacteria is responsible for the synthesis of 5-aminolevulinic acid, which forms the core skeleton of cofactors required for metabolism. One of the key actors in this pathway is a pyridoxamine-5'-phosphate (PMP)/pyridoxal-5'-phosphate (PLP) dependent enzyme called glutamate-1-semialdehyde aminomutase (GSAM). In this study, we crystallized the expression product of the uncharacterized pa4088 gene from the opportunistic pathogen Pseudomonas aeruginosa PAO1. The resulting high-resolution structure confirms it to be a member of the GSAM family. Continuous electron density indicates the presence of a PLP cofactor with a Schiff base linkage between the PLP cofactor and the ε-amino group of Lys286. A crystal structure of a K286A mutant in complex with PMP is also reported. As GSAM enzymes are not present in mammalian cells, this work provides a starting point for the investigation of GSAM as a target for drug development against P. aeruginosa infection.
细菌中的 C5 途径负责合成 5-氨基乙酰丙酸，它构成了代谢所需辅因子的核心骨架。该途径中的一个关键因素是一种吡哆醛-5'-磷酸 (PMP)/吡哆醇-5'-磷酸 (PLP) 依赖性酶，称为谷氨酸-1-半醛氨基转移酶 (GSAM)。在这项研究中，我们从机会性病原体铜绿假单胞菌 PAO1 中表达和结晶了未鉴定的 pa4088 基因的表达产物。由此产生的高分辨率结构证实它是 GSAM 家族的一员。连续的电子密度表明存在 PLP 辅因子，PLP 辅因子和 Lys286 的ε-氨基之间存在希夫碱键。还报道了一个与 PMP 结合的 K286A 突变体的晶体结构。由于哺乳动物细胞中不存在 GSAM 酶，这项工作为研究 GSAM 作为治疗铜绿假单胞菌感染的药物靶点提供了一个起点。
