6VAX

Crystal structure of human SDHA-SDHAF2 assembly intermediate

Summary for 6VAX

• Entry DOI: 10.2210/pdb6vax/pdb
• Descriptor: Succinate dehydrogenase [ubiquinone] flavoprotein subunit, mitochondrial, Succinate dehydrogenase assembly factor 2, mitochondrial, FLAVIN-ADENINE DINUCLEOTIDE, ... (9 entities in total)
• Functional Keywords: sdha, flavoprotein, sdhaf2, assembly intermediate, respiratory complex, oxidoreductase
• Biological source: Homo sapiens (Human); More
• Total number of polymer chains: 4
• Total formula weight: 180841.97

Authors

Sharma, P.,Maklashina, E.,Cecchini, G.,Iverson, T.M. (deposition date: 2019-12-18, release date: 2020-08-26, Last modification date: 2023-10-25)

Primary citation

Sharma, P.,Maklashina, E.,Cecchini, G.,Iverson, T.M.
The roles of SDHAF2 and dicarboxylate in covalent flavinylation of SDHA, the human complex II flavoprotein.
Proc.Natl.Acad.Sci.USA, 117:23548-23556, 2020

PubMed Abstract: Mitochondrial complex II, also known as succinate dehydrogenase (SDH), is an integral-membrane heterotetramer (SDHABCD) that links two essential energy-producing processes, the tricarboxylic acid (TCA) cycle and oxidative phosphorylation. A significant amount of information is available on the structure and function of mature complex II from a range of organisms. However, there is a gap in our understanding of how the enzyme assembles into a functional complex, and disease-associated complex II insufficiency may result from incorrect function of the mature enzyme or from assembly defects. Here, we investigate the assembly of human complex II by combining a biochemical reconstructionist approach with structural studies. We report an X-ray structure of human SDHA and its dedicated assembly factor SDHAF2. Importantly, we also identify a small molecule dicarboxylate that acts as an essential cofactor in this process and works in synergy with SDHAF2 to properly orient the flavin and capping domains of SDHA. This reorganizes the active site, which is located at the interface of these domains, and adjusts the pK of SDHA so that covalent attachment of the flavin adenine dinucleotide (FAD) cofactor is supported. We analyze the impact of disease-associated SDHA mutations on assembly and identify four distinct conformational forms of the complex II flavoprotein that we assign to roles in assembly and catalysis.

PubMed: 32887801
DOI: 10.1073/pnas.2007391117

Experimental method

X-RAY DIFFRACTION (2.59 Å)