4RHP

Crystal structure of human COQ9 in complex with a phospholipid, Northeast Structural Genomics Consortium Target HR5043

Summary for 4RHP

• Entry DOI: 10.2210/pdb4rhp/pdb
• Descriptor: Ubiquinone biosynthesis protein COQ9, mitochondrial, DI-PALMITOYL-3-SN-PHOSPHATIDYLETHANOLAMINE (3 entities in total)
• Functional Keywords: structural genomics, psi-biology, northeast structural genomics consortium, nesg, all alpha-helical protein, ubiquinone biosynthesis, mitochondrial, mitochondrial protein partnership, mpp, biosynthetic protein
• Biological source: Homo sapiens (human)
• Total number of polymer chains: 2
• Total formula weight: 54875.46

Authors

Forouhar, F.,Lew, S.,Seetharaman, J.,Wang, H.,Lee, D.,Kogan, S.,Maglaqui, M.,Xiao, R.,Everett, J.K.,Montelione, G.T.,Hunt, J.F.,Tong, L.,Northeast Structural Genomics Consortium (NESG),Mitochondrial Protein Partnership (MPP) (deposition date: 2014-10-02, release date: 2014-10-22, Last modification date: 2024-10-16)

Primary citation

Lohman, D.C.,Forouhar, F.,Beebe, E.T.,Stefely, M.S.,Minogue, C.E.,Ulbrich, A.,Stefely, J.A.,Sukumar, S.,Luna-Sanchez, M.,Jochem, A.,Lew, S.,Seetharaman, J.,Xiao, R.,Wang, H.,Westphall, M.S.,Wrobel, R.L.,Everett, J.K.,Mitchell, J.C.,Lopez, L.C.,Coon, J.J.,Tong, L.,Pagliarini, D.J.
Mitochondrial COQ9 is a lipid-binding protein that associates with COQ7 to enable coenzyme Q biosynthesis.
Proc.Natl.Acad.Sci.USA, 111:E4697-E4705, 2014

PubMed Abstract: Coenzyme Q (CoQ) is an isoprenylated quinone that is essential for cellular respiration and is synthesized in mitochondria by the combined action of at least nine proteins (COQ1-9). Although most COQ proteins are known to catalyze modifications to CoQ precursors, the biochemical role of COQ9 remains unclear. Here, we report that a disease-related COQ9 mutation leads to extensive disruption of the CoQ protein biosynthetic complex in a mouse model, and that COQ9 specifically interacts with COQ7 through a series of conserved residues. Toward understanding how COQ9 can perform these functions, we solved the crystal structure of Homo sapiens COQ9 at 2.4 Å. Unexpectedly, our structure reveals that COQ9 has structural homology to the TFR family of bacterial transcriptional regulators, but that it adopts an atypical TFR dimer orientation and is not predicted to bind DNA. Our structure also reveals a lipid-binding site, and mass spectrometry-based analyses of purified COQ9 demonstrate that it associates with multiple lipid species, including CoQ itself. The conserved COQ9 residues necessary for its interaction with COQ7 comprise a surface patch around the lipid-binding site, suggesting that COQ9 might serve to present its bound lipid to COQ7. Collectively, our data define COQ9 as the first, to our knowledge, mammalian TFR structural homolog and suggest that its lipid-binding capacity and association with COQ7 are key features for enabling CoQ biosynthesis.

PubMed: 25339443
DOI: 10.1073/pnas.1413128111

Experimental method

X-RAY DIFFRACTION (2.393 Å)