Maize cDNAs expressed in endosperm encode functional farnesyl diphosphate synthase with geranylgeranyl diphosphate...

Area of Science:

• Plant biochemistry
• Natural product biosynthesis
• Molecular biology

Background:

• Isoprenoids are vital and diverse natural products in plants.
• Farnesyl diphosphate (FPP) and geranylgeranyl diphosphate (GGPP) are key precursors for numerous essential plant compounds.
• Farnesyl diphosphate synthase (FPPS) and geranylgeranyl diphosphate synthase (GGPPS) catalyze the production of FPP and GGPP.

Purpose of the Study:

• To isolate and characterize maize (Zea mays L. cv B73) endosperm cDNAs encoding isoprenoid synthases.
• To investigate the enzymatic activity and substrate specificity of these maize enzymes.
• To explore the potential for harnessing enzyme bifunctionality in metabolic engineering.

Main Methods:

• Functional complementation of Escherichia coli mutant strains lacking GGPPS activity.
• In vitro enzymatic assays to determine FPP and GGPP production.
• Sequence analysis to identify conserved motifs and homology with known prenyltransferases.

Main Results:

• Maize cDNAs encoding bifunctional FPPS/GGPPS enzymes were successfully isolated.
• These enzymes produce both FPP and GGPP, with the ratio influenced by the N-terminal sequence.
• The maize enzymes demonstrated functionality in E. coli, enabling isoprenoid substrate supply for pathways.

Conclusions:

• The identified maize enzymes exhibit dual FPPS and GGPPS activity, a characteristic influenced by their structure.
• Enzyme bifunctionality can be effectively utilized in metabolic engineering for isoprenoid pathway optimization.
• These maize cDNAs are valuable resources for studying prenyl transferase specificity and enhancing isoprenoid production in cereal crops.