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The genes coding for all the enzymes involved in the conversion of acetyl-CoA to farnesyl diphosphate (FPP) in the zeaxanthin-producing bacterium Paracoccus zeaxanthinifaciens were cloned and characterized. Two genes encoding enzymes catalysing the condensation of two acetyl-CoA molecules to acetoacetyl-CoA were found. The six enzymes involved in the conversion of acetyl-CoA and acetoacetyl-CoA to isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP) are grouped in an operon, designated the mevalonate operon. The gene encoding the enzyme catalysing two consecutive condensations, IPP and DMAPP to geranyl diphosphate (GPP) and IPP and GPP to FPP, is not clustered with any other gene encoding an enzyme of the isoprenoid pathway. Genes encoding enzymes involved in the biosynthesis of poly-hydroxyalkanoate and non-carotenoid isoprenoids found in P. zeaxanthinifaciens are also presented. [Copyright &y& Elsevier]

Dolichol, an isoprenoid lipid, known mainly for its function in protein glycosylation, is synthesised in the mevalonate pathway. The pathway is highly regulated, on multiple levels, by sterol and non-sterol derivatives of mevalonic acid. Farnesyl diphosphate (FPP) and/or FPP-derived molecules have been identified as the main non-sterol compounds regulating degradation of 3-hydroxy-3-methylglutaryl-CoA reductase, one of the regulatory enzymes in the mevalonate pathway. In the present review we concentrate on the effect of overexpression of farnesyl diphosphate synthase on dolichol biosynthesis in yeast. In this context the role of the Yta7 protein, belonging to the AAA ATPase family, in the regulation of FPP flux to the dolichol branch of the mevalonate pathway is discussed, and the effect of FPP and/or derived molecules on the transcription of genes encoding the first enzyme committed to dolichol biosynthesis, i.e. cis-prenyl transferase. [ABSTRACT FROM AUTHOR]