Department of Chemistry, Rutgers University, Newark, NJ 07102, USA.
Molecules. 2013 Sep 26;18(10):11873-903. doi: 10.3390/molecules181011873.
The 2-oxoacid dehydrogenase complexes (ODHc) consist of multiple copies of three enzyme components: E1, a 2-oxoacid decarboxylase; E2, dihydrolipoyl acyl-transferase; and E3, dihydrolipoyl dehydrogenase, that together catalyze the oxidative decarboxylation of 2-oxoacids, in the presence of thiamin diphosphate (ThDP), coenzyme A (CoA), Mg²⁺ and NAD⁺, to generate CO₂, NADH and the corresponding acyl-CoA. The structural scaffold of the complex is provided by E2, with E1 and E3 bound around the periphery. The three principal members of the family are pyruvate dehydrogenase (PDHc), 2-oxoglutarate dehydrogenase (OGDHc) and branched-chain 2-oxo acid dehydrogenase (BCKDHc). In this review, we report application of NMR-based approaches to both mechanistic and structural issues concerning these complexes. These studies revealed the nature and reactivity of transient intermediates on the enzymatic pathway and provided site-specific information on the architecture and binding specificity of the domain interfaces using solubilized truncated domain constructs of the multi-domain E2 component in its interactions with the E1 and E3 components. Where studied, NMR has also provided information about mobile loops and the possible relationship of mobility and catalysis.
2-氧代酸脱氢酶复合物（ODHc）由三种酶成分的多个拷贝组成：E1，2-氧代酸脱羧酶；E2，二氢硫辛酸酰基转移酶；E3，二氢硫辛酸脱氢酶，它们共同催化 2-氧代酸的氧化脱羧，在硫胺素二磷酸（ThDP）、辅酶 A（CoA）、Mg²⁺和 NAD⁺的存在下，生成 CO₂、NADH 和相应的酰基辅酶 A。复合物的结构支架由 E2 提供，E1 和 E3 结合在其周围。该家族的三个主要成员是丙酮酸脱氢酶（PDHc）、2-酮戊二酸脱氢酶（OGDHc）和支链 2-氧代酸脱氢酶（BCKDHc）。在这篇综述中，我们报告了基于 NMR 的方法在这些复合物的机制和结构问题上的应用。这些研究揭示了酶促途径中瞬态中间体的性质和反应性，并使用可溶性截断的 E2 成分的结构域构建体，提供了关于结构域界面的架构和结合特异性的特定于位点的信息，这些构建体与 E1 和 E3 成分相互作用。在研究的情况下，NMR 还提供了关于可移动环和可能的流动性和催化关系的信息。
