Molecular cloning, expression and characterization of the first three genes in the mevalonate-independent isoprenoid pathway in Streptomyces coelicolor

The mevalonate-independent biosynthetic pathway to isopentenyl diphosphate and dimethylallyl diphosphate, the universal precursors to the isoprenoids, operates in eubacteria, including Escherichia coli, in algae, and in the p lastids of higher plants. A search of the Sanger Centre Streptomyces coelic olor genome database revealed open reading frames with ca. 40-50% identity at the deduced amino acid level to the first three E. coli enzymes of this pathway, corresponding to deoxyxylulose phosphate synthase, deoxyxylulose p hosphate reductoisomerase and 2-C-methyl erythritol 4-phosphate cytidylyltr ansferase. The S. coelicolor genes have been cloned and expressed in E. col i, and the recombinant proteins characterized physically and kinetically. T he presence of the corresponding enzyme activities in extracts of S. coelic olor CH999 further supports the operation of the mevalonate-independent pat hway in this organism. (C) 2001 Elsevier Science Ltd. All rights reserved.