MOLECULAR-CLONING OF THE PYRE GENE FROM THE EXTREME THERMOPHILE THERMUS-FLAVUS

Mutants of the extreme thermophile Thermus flavus in the pyrimidine bi osynthetic pathway (Pyr(-)) were isolated by resistance to 5-fluorooro tic acid. The pyrE gene, which codes for the orotate phosphoribosyltra nsferase, was cloned by recombination with one of the isolated Pyr(-) T. flavus mutant strains. It was subcloned by complementation of an Es cherichia coli pyrE mutant strain and was sequenced. The deduced polyp eptide sequence extends over 183 amino acids. Several independent Pyr( -) mutations were mapped within the pyrE locus by recombination with f ragments of the cloned gene.