Fig. 1.

Schematic overview of synthesis pathway (a) and expression constructs containing the pathway genes (b). GPP and FPP are synthesized by IspA* and IspA, respectively, through condensations of DMAPP and IPP, generated from the MVA pathway. NudB catalyzes dephosphorylation of IPP, DMAPP, GPP, and FPP into IP, DMAP, GP, and FP, respectively. AphA catalyzes hydrolysis of IP, DMAP, GP, and FP into isoprenol, prenol, geraniol, and farnesol, respectively. Chloramphenicol acetyltransferase (CAT) is responsible for transformation of isoprenol, prenol, and geraniol into their corresponding acetate esters. An alcohol dehydrogenase, YjgB oxidizes geraniol and farnesol into citral and farnesal, respectively. An unknown acetyl transferase (ATF) is involved in transformation of farnesol into farnesyl acetate. Solid colored arrows and black bent arrows represent genes and promoters, respectively. Abbreviations of the pathway intermediates are as follows: MVA, mevalonate; IPP, isopentenyl diphosphate; DMAPP, dimethylallyl diphosphate; GPP, geranyl diphosphate; FPP, farnesyl diphosphate; IP, isopentenyl phosphate; DMAP, dimethylallyl phosphate; GP, geranyl phosphate; FP, farnesyl phosphate. The abbreviations of enzymes are as follows: NudB, dihydroneopterin triphosphate diphosphatase; IspA, farnesyl diphosphate synthase; AphA, acid phosphatase; IspA*, IspA mutant of geranyl diphosphate synthase; MvaE, bifunctional acetoacetyl-CoA thiolase and HMG-CoA reductase; MvaS, HMG-CoA synthase; MvaK1, mevalonate kinase; MvaK2, phosphomevalonate kinase; MvaD, mevalonate diphosphate decarboxylase; IDI, isopentenyl diphosphate isomerase; CAT, chloramphenicol acetyltransferase; YjgB NADPH-dependent aldehyde reductases; ?ATF, unknown acetyl transferase of E. coli