Open reading frame 176 in the photosynthesis gene cluster of Rhodobacter capsulatus encodes idi, a gene for isopentenyl diphosphate isomerase.

AUTOR(ES)

Hahn, F M

RESUMO

Isopentenyl diphosphate (IPP) isomerase catalyzes an essential activation step in the isoprenoid biosynthetic pathway. A database search based on probes from the highly conserved regions in three eukaryotic IPP isomerases revealed substantial similarity with ORF176 in the photosynthesis gene cluster in Rhodobacter capsulatus. The open reading frame was cloned into an Escherichia coli expression vector. The encoded 20-kDa protein, which was purified in two steps by ion exchange and hydrophobic interaction chromatography, catalyzed the interconversion of IPP and dimethylallyl diphosphate. Thus, the photosynthesis gene cluster encodes all of the enzymes required to incorporate IPP into the ultimate carotenoid and bacteriochlorophyll metabolites in R. capsulatus. More recent searches uncovered additional putative open reading frames for IPP isomerase in seed-bearing plants (Oryza sativa, Arabadopsis thaliana, and Clarkia breweri), a worm (Caenorhabiditis elegans), and another eubacterium (Escherichia coli). The R. capsulatus enzyme is the smallest of the IPP isomerases to be identified thus far and may consist mostly of a fundamental catalytic core for the enzyme.

Documentos Relacionados

• Escherichia coli Open Reading Frame 696 Is idi, a Nonessential Gene Encoding Isopentenyl Diphosphate Isomerase
• 1-Deoxy-d-Xylulose 5-Phosphate Synthase, the Gene Product of Open Reading Frame (ORF) 2816 and ORF 2895 in Rhodobacter capsulatus
• An unusual isopentenyl diphosphate isomerase found in the mevalonate pathway gene cluster from Streptomyces sp. strain CL190
• Crystal structure of isopentenyl diphosphate:dimethylallyl diphosphate isomerase
• Regulated Expression of a Highly Conserved Regulatory Gene Cluster Is Necessary for Controlling Photosynthesis Gene Expression in Response to Anaerobiosis in Rhodobacter capsulatus