Juvenile hormone biosynthesis in M. sexta: Substrate specificity of insect prenyltransferase utilizing homologous diphosphate analogs

Cloning, expression and characterization of a dipteran farnesyl diphosphate synthase

“…Given that the Lepidoptera are known to produce homologous JH structures and that this capability is believed to be associated, at least in part, with the substrate specificity of FPPS of the corpora allata (the endocrine glands that produce JH, Sen et al, 2006), we were interested in determining whether DmFPPS had substrate specificity and enzymological properties similar to those of lepidopteran prenyltransferase. The latter has only recently been assessed using recombinant enzymes (Sen et al, 2007a), while two FPPSs (FPPS I and FPPS II) have been purified from Bombyx mori (Koyama et al, 1985) and another one has been isolated from Manduca sexta (Sen and Sperry, 2002).…”

Rational design of Lepidoptera-specific insecticidal inhibitors targeting farnesyl diphosphate synthase, a key enzyme of the juvenile hormone biosynthetic pathway

“…10) This has been corroborated by studies where the lepidopteran enzyme was shown to display greater steric latitude around the C-3 and C-7 alkyl position of DMAPP and GPP, compared with pig liver FPPS. 55) When comparing the sequences and homology models of type-1 and type-2 FPPSs (FPPS1 and FPPS2), the type-2 enzyme has a more "conventional" active site, though variable non-aromatic residues at position -4 from the FARM have been observed. Initial docking studies showed FPPS1 as having greater binding affinity for homologous GPP substrates and FPP products.…”

“…58) A first series of compounds aimed at disrupting insect growth through FPPS inhibition was synthesized and evaluated by Sen et al 59) It was hypothesized that appropriately N-alkylated BPs can provide selective binding to the C-3 binding region of lepidopteran FPPS2, based on the observation that homologous allylic substrates such as HDMAPP and bishomogeranyl diphosphate (BHGPP, precursor to JH0 and JH1) contain C-3 alkyl substituents that are larger than in DMAPP and GPP, and because C-3 alkyl analogs of DMAPP were shown to be readily accommodated by the prenyltransferase of M. sexta CA. 55) Thus a series of N-alkylated ortho-substituted pyridinium BPs (Fig. 5) were chosen as candidates for selective inhibition of FPPS2, following docking of potential structures in the active site of a homology model of spruce budworm (C. fumiferana) FPPS.…”

Omics approaches to study juvenile hormone synthesis

“…The small size of the endocrine gland precluded the purification and characterization of CA proteins; consequently, most of the information we have on JH biosynthetic enzymes is based on the analysis of recombinant protein activities, or homology modeling and docking simulations [30]. Biochemical characterization of purified or recombinant enzymes of the MVAP and JH-branch in insects have been reported for acetoacetyl-CoA thiolase [31], HMG-CoA synthase [32,33], mevalonate kinase [34] isopentenyl-PP isomerase [35,36], farnesyl-PP synthase [37,38,39,40,41,42] farnesyl pyrophosphatase [15,43], farnesol dehydrogenase [16], farnesal dehydrogenase [17], JHAMT [18,44,45,46,47], and EPOX [19,48,49]. In addition, the activities of 8 of the 13 JH biosynthetic enzymes have now been monitored in vitro in CA extracts of mosquitoes under 5 different developmental and physiological conditions [7].…”