Cloning, expression and characterization of lepidopteran isopentenyl diphosphate isomerase

► Isopentenyl diphosphate isomerase of the spruce budworm (C. fumiferana) and the tobacco hornworm (M. sexta) was cloned. ► C. fumiferana isopentenyl diphosphate isomerase (IPPI) was expressed and characterized. ► A homology model of C. fumiferana was developed. ► Mutagenesis and inhibitor studies were performed to establish structural differences between lepidopteran and other IPPIs. ► The regiospecificity of homologous IPP isomerization by C. fumiferana IPPI was assessed.