InterPro domain: IPR006370

Members of this family show a broad specificity for prenyl diphosphates, accepting substrates of different chain lengths. Genes coding for these enzymes have been identified in many organisms, and are mostly responsible for ubiquinone (UQ) biosynthesis [ 1 , 2 , 3 ]. 4-hydroxybenzoate solanesyltransferase from cyanobacteria displays a broad specificity with regard to the prenyl donor substrate and uses not only solanesyl diphosphate, but also a number of shorter-chain prenyl diphosphates [ 4 ]. One exception is LePGT1 (Lithospermum erythrorhizon 4-hydroxybenzoic acid geranyltransferase), which only accepts GPP (geranyl diphosphate) and is involved in the biosynthesis of a red naphthoquinone, shikonin, a plant secondary metabolite [ 5 ]. LePGT1 was reported to be the key regulatory enzyme of shikonin biosynthesis [ 6 ] and is not relevant to the formation of UQ [ 7 ].

1. The AtPPT1 gene encoding 4-hydroxybenzoate polyprenyl diphosphate transferase in ubiquinone biosynthesis is required for embryo development in Arabidopsis thaliana. Plant Mol. Biol. 55, 567-77
2. Functional characterization of OsPPT1, which encodes p-hydroxybenzoate polyprenyltransferase involved in ubiquinone biosynthesis in Oryza sativa. Plant Cell Physiol. 47, 581-90
3. Isolation and functional expression of human COQ2, a gene encoding a polyprenyl transferase involved in the synthesis of CoQ. Biochem. J. 382, 519-26
4. Plastoquinone-9 biosynthesis in cyanobacteria differs from that in plants and involves a novel 4-hydroxybenzoate solanesyltransferase. Biochem. J. 442, 621-9
5. Functional characterization of LePGT1, a membrane-bound prenyltransferase involved in the geranylation of p-hydroxybenzoic acid. Biochem. J. 421, 231-41
6. Partial purification and properties of geranyl pyrophosphate synthase from Lithospermum erythrorhizon cell cultures. Arch. Biochem. Biophys. 273, 331-8
7. Geranyl diphosphate:4-hydroxybenzoate geranyltransferase from Lithospermum erythrorhizon. Cloning and characterization of a ket enzyme in shikonin biosynthesis. J. Biol. Chem. 277, 6240-6