Biochemical characterization and genetic mapping of purine genes inMicrococcus luteus

Abstract

SUMMARYPurine auxotrophs ofMicrococcus luteuswere induced byN-methyl-N′-nitro-N-nitrosoguanidine. They were biochemically characterized by growth stimulation with CO2-enriched air and purine intermediates and by the Bratton-Marshall test that is used to detect accumulated diazotizable amines. The mutants were divided into four classes:pur(EC),purH,purJ, andPur−. Thepur(EC) class was further subdivided intopurEandpurCby results of crossing all thepur(EC) mutants with a knownpurEreference strain (ATCC 27141). Mutants which were not linked to the referencepurEmarker were considered to bepurC. Genetic mapping was accomplished by using two-point reciprocal transformation crosses. The result of this study indicates thatpurJmutants may be loosely linked topurEandpurC, and purH mutants are not linked topurE,purCorpurJ.