Mutation of an inosine-producing strain of Bacillus subtilis to DL-methionine sulfoxide resistance for guanosine production.
An inosine-producing strain of Bacillus subtilis was mutated to resistance against the antagonist of glutamine, DL-methionine sulfoxide. Among the mutants derived, guanosine producers were observed frequently. The best strain, 14119, produced 9.6 g of guanosine per liter at a weight yield of 12% from consumed sugar. Inosine production decreased concomitantly. When resistance was increased further by exposure to higher doses of DL-methionine sulfoxide, another strain, AG169, was obtained that did not excrete inosine but produced increased amounts of xanthosine. In these strains, the specific activity of 5'-nucleotidase was lower and that of inosine 5'-monophosphate (IMP) dehydrogenase was higher than the parent strain. It is speculated that the metabolic flow from IMP to xanthosine 5'-monophosphate proceeds more smoothly than that from IMP  to inosine and yields more xanthosine and guanosine.
D001412:Bacillus subtilis / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D004352:Drug Resistance, Microbial; D005974:Glutamate-Ammonia Ligase / Q000378:metabolism; D006151:Guanosine / Q000096:biosynthesis*; D006157:Guanosine Monophosphate; D007168:IMP Dehydrogenase / Q000378:metabolism; D007288:Inosine / Q000096:biosynthesis; D008025:Ligases / Q000378:metabolism; D008715:Methionine / Q000031:analogs & derivatives* / Q000494:pharmacology; D009154:Mutation; D009708:Nucleotidases / Q000378:metabolism
D006151:Guanosine; D007288:Inosine; D006157:Guanosine Monophosphate; D008715:Methionine; D007168:IMP Dehydrogenase; D009708:Nucleotidases; D008025:Ligases; D005974:Glutamate-Ammonia Ligase