北京大学马明团队研究了两种硫胺素二磷酸依赖酶的结构见解及其在碳-碳键反应中的合成应用。这一研究成果于2025年5月14日发表在《自然-化学》杂志上。

α-羟基-β-酮酸合酶是二磷酸硫胺素依赖性酶，在初级代谢产物和各种次级代谢产物的生物合成中催化碳-碳键反应。然而，人们对α-羟基-β-酮酸合酶的底物选择性和催化立体选择性知之甚少，极大地阻碍了它们在生成各种碳骨架中的合成应用。研究组报道了两种新的α-羟基-β-酮酸合酶CsmA和BbmA的发现，它们在催化两种β-酮酸类之间的碳-碳偶联反应中显示出不同的底物选择性。 

他们测定了CsmA或BbmA与二磷酸硫胺素及其底物的四种晶体结构，清楚地揭示了它们底物选择性和催化立体选择性的结构基础。底物范围的扩大产生了120个α-羟基-β-酮酸和240个NaBH₄还原产物。此外，研究组将CsmA和BbmA应用于酶促全合成，产生了36种含呋喃内酯的γ-丁内酯。这些结果为α-羟基-β-酮酸合酶的催化提供了新的结构见解，并突显了它们在碳连接催化和合成应用中的巨大潜力。

附：英文原文

Title: Structural insights into two thiamine diphosphate-dependent enzymes and their synthetic applications in carbon–carbon linkage reactions

Author: Liu, Tan, Wang, Guiyang, Yu, Jiahui, Li, Mengyuan, Peng, Tianbo, Wang, Jie, Li, Houhua, Su, Xiao-dong, Jiang, Changtao, Ye, Min, Yang, Donghui, Ma, Ming

Issue&Volume: 2025-05-14

Abstract: The α-hydroxy-β-keto acid synthases are thiamine diphosphate-dependent enzymes catalysing carbon–carbon linkage reactions in the biosynthesis of primary metabolites and various secondary metabolites. However, the substrate selectivity and catalytic stereoselectivity of α-hydroxy-β-keto acid synthases are poorly understood, greatly hindering their synthetic application in generating diverse carbon frameworks. We here report the discovery of two new α-hydroxy-β-keto acid synthases CsmA and BbmA, which show different substrate selectivities in catalysing carbon–carbon coupling reactions between two β-keto acids. Four crystal structures of CsmA or BbmA complexed with thiamine diphosphate and their substrates were determined, clearly revealing their structural bases of substrate selectivity and catalytic stereoselectivity. Substrate scope expansion enables us to generate 120 α-hydroxy-β-keto acids together with 240 NaBH4-reduction products. Furthermore, we applied CsmA and BbmA into enzymatic total synthesis, generating 36 γ-butyrolactone-containing furanolides. These results provide new structural insights into the catalyses of α-hydroxy-β-keto acid synthases and highlight their great potential in carboligation catalysis and synthetic applications.

DOI: 10.1038/s41557-025-01822-y

Source: https://www.nature.com/articles/s41557-025-01822-y