Lipid-binding protein involved in the biosynthesis of coenzyme Q, also named ubiquinone, an essential lipid-soluble electron transporter for aerobic cellular respiration. Binds a phospholipid of at least 10 carbons in each acyl group. May be required to present its bound-lipid to COQ7. Cofactor biosynthesis; ubiquinone biosynthesis. Homodimer. Interacts with COQ7. Structurally similar to the bacterial FadR protein (fatty acid metabolism regulator protein). Belongs to the COQ9 family.