STUDY OF RIBOFLAVIN OPERON IN BACILLUS-SUBTILIS .9. PROPERTIES OF MUTANTS RESISTANT TO LUMIFLAVIN OR LUMICHROME

  • 1 January 1975
    • journal article
    • research article
    • Vol. 11  (8) , 129-138
Abstract
Lumiflavine and lumichrome inhibit the growth of different strains of B. subtilis, including a riboflavin-constitutive mutant. Lumiflavine has no regulatory effect, but lumichrome is an effector and participates in the repression of riboflavin precursor synthesis and riboflavin synthetase synthesis. Mutants resistant to lumiflavine or lumichrome accumulate a mixture of riboflavin, FMN and FAD. Their regulatory characteristics are substantially altered. They are repressed by higher concentrations of all effectors compared with the wild type. The mapping of resistant mutants showed that most mutations are located near (probably inside of) the ribC gene. The simultaneous presence of all 3 flavins in the cultural medium shows that the regulatory protein is universal to the biosynthesis of all flavins.