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

Restriction fragment analysis of the DNA from Rhodobacter capsulatus isolated an open reading frame 176 in the photosynthesis gene cluster. DNA sequence analysis identified idi, a gene for isopentenyl diphosphate isomerase, a catalytic enzyme involved in the activation of the isoprenoid biosynthetic pathway. This enzyme has been previously shown to be present in other seed-bearing plants.