Molecular cloning, expression profiling and functional analysis of a DXR gene encoding 1-deoxy-D-xylulose 5-phosphate reductoisomerase from Camptotheca acuminata

As the second enzyme of the non-mevalonate terpenoid pathway for isopentenyl diphosphate biosynthesis, DXP reductoisomerase (DXR, EC: 1.1.1.267) catalyzes a committed step of the MEP pathway for camptothecin (CPT) biosynthesis. In order to understand more about the role of DXR involved in the CPT biosynthesis at the molecular Level, the full-Length DXR cDNA sequence (designated as CaDXR) was isolated and characterized for the first time from a medicinal Nyssaceae plant species, Camptotheca acuminata. The full-Length cDNA of CaDXR was 1823 bp containing a 1416 bp open reading frame (ORF) encoding a polypeptide of 472 amino acids. Comparative and bioinformatic analyses revealed that CaDXR showed extensive homology with DXRs from other plant species and contained a conserved