Temperature-sensitive mutant of the obligate methylotroph Methylobacillus flagellatum KT deficient in glucose-6-phosphate dehydrogenase
Kletsova, L.V.; Chibisova, E.S.; Tsygankov, I.D.
Molekuliarnaia Genetika Mikrobiologiia i Virusologiia 7: 39-44
1987
ISSN/ISBN: 0208-0613 PMID: 3118203 Document Number: 289664
The common approach is developed for isolation of mutants deficient in key enzymes of ribulose monophosphate pathway for formaldehyde oxidation and assimilation by obligate methylotrophic bacteria. The approach is based on total isolation of temperature sensitive mutants and their biochemical characterization. A number of ts- mutants of obligate methylotroph M. flagellatum KT is isolated following nitrosoguanidine induced mutagenesis. The modified screening method was developed and used for identification of mutants deficient in the key enzymes of ribulose monophosphate pathway. The mutant deficient in glucose-6-phosphate dehydrogenase (zwf) was identified. The NAD-dependent activity of glucose-6-phosphate dehydrogenase was not measurable under nonpermissive temperature while the level of NADP-dependent activity was only four-fold less comparing with wild type strain. It was concluded that growth limitation of zwf mutant of M. flagellatum KT (designated T623) at 42 degrees C results from the absence of NAD-dependent activity of glucose-6-phosphate dehydrogenase.