Department of Biological Science and Technology, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan.
Acta Crystallogr F Struct Biol Commun. 2023 Jul 1;79(Pt 7):193-199. doi: 10.1107/S2053230X23005769. Epub 2023 Jul 5.
L-2,3-Diaminopropionic acid (L-Dap) is a nonproteinogenic amino acid that plays as an important role as a building block in the biosynthesis of several natural products, including capreomycin, viomycin, zwittermicin, staphyloferrin and dapdiamide. A previous study reported that CmnB and CmnK are two enzymes that are involved in the formation of L-Dap in the biosynthesis of capreomycin. CmnB catalyzes the condensation reaction of O-phospho-L-serine and L-glutamic acid to generate N-(1-amino-1-carboxyl-2-ethyl)glutamic acid, which subsequently undergoes oxidative hydrolysis via CmnK to generate the product L-Dap. Here, the crystal structure of CmnB in complex with the reaction intermediate PLP-α-aminoacrylate is reported at 2.2 Å resolution. Notably, CmnB is the second known example of a PLP-dependent enzyme that forms a monomeric structure in crystal packing. The crystal structure of CmnB also provides insights into the catalytic mechanism of the enzyme and supports the biosynthetic pathway of L-Dap reported in previous studies.
L-2,3-二氨基丙酸（L-Dap）是一种非蛋白氨基酸，作为构建块在几种天然产物的生物合成中发挥着重要作用，包括卡那霉素、威霉素、两性霉素、葡萄球菌铁蛋白和 dapdiamide。先前的一项研究报道，CmnB 和 CmnK 是卡那霉素生物合成中参与 L-Dap 形成的两种酶。CmnB 催化 O-磷酸-L-丝氨酸和 L-谷氨酸的缩合反应，生成 N-（1-氨基-1-羧基-2-乙基）谷氨酸，随后通过 CmnK 发生氧化水解，生成产物 L-Dap。在此，报道了 CmnB 与反应中间体 PLP-α-氨基丙烯酸复合物的晶体结构，分辨率为 2.2 Å。值得注意的是，CmnB 是第二个已知的形成单体结构的 PLP 依赖性酶的例子。CmnB 的晶体结构还提供了对酶的催化机制的深入了解，并支持了先前研究中报道的 L-Dap 的生物合成途径。
