Zhang, Xu. Study of the structures and interactions of components in 2-oxoglutarate dehydrogenase complex and 2-oxoadipate dehydrogenase complex. Retrieved from https://doi.org/doi:10.7282/t3-p1yx-4b15
DescriptionMultienzyme complexes are assemblies containing several copies of one or several enzymes, and they generally carry out sequential catalytic transformations. Multienzyme complexes are essential for the living organisms, therefore deciphering how the components behave in isolation, but also how they interact with each other is critical for understanding the functions of enzyme complexes. The 2-oxoglutarate (OG) dehydrogenase complex (OGDHc) is a central enzyme in all forms of aerobic metabolism catalyzing the oxidative decarboxylation of OG, generating succinyl-CoA and NADH. The 2-oxoadipate dehydrogenase complex (OADHc) is a novel multienzyme complex functioning on the final degradation pathway of L-lysine, L-hydroxylysine and L-tryptophan. Many findings have suggested interesting similarities and differences between these two enzyme complexes, especially the unprecedented sharing of the dihydrolipamide acyltransferase component. In this thesis, hydrogen-deuterium exchange mass spectrometry (HDX-MS) and chemical cross-linking mass spectrometry (CL-MS), along with other biochemical methods and computational modeling, were employed to study the assembly of human OGDHc. In addition, studies were also carried out to investigate the functional and structural consequences of the mutation on the DHTKD1 gene encoding the 2-oxoadipate dehydrogenase. Moreover, HDX-MS was used to study the conformational changes induced by substitution of active center histidines in E. coli 1-deoxy-D-xylulose 5-phosphate (DXP) synthase, a thiamin diphosphate dependent enzyme.