The Aeration-Dependent Effect of Vitamin B12 on DNA Biosynthesis in Methylobacterium dichloromethanicum |
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| Authors: | Danilova I. V. Doronina N. V. Trotsenko Yu. A. Netrusov A. I. Ryzhkova (Iordan) E. P. |
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| Affiliation: | (1) Department of Microbiology, Faculty of Biology, Moscow State University, Vorob'evy gory, Moscow, 119992, Russia;(2) Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, pr. Nauki 5, Pushchino, Moscow oblast, 142290, Russia |
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| Abstract: | The effect of vitamin B12 (cobalamin) on DNA biosynthesis in Methylobacterium dichloromethanicum was studied. When cultivated in media with methanol or dichloromethane, the bacterium produced approximately 10  g corrinoids per gram dry biomass, compared to about 7 g/g when cultivated on ethanol or succinate. Exogenous adenosylcobalamin (AdoCbl) stimulated DNA biosynthesis in M. dichloromethanicum cells grown under poor aeration, the effect being mediated by AdoCbl-dependent ribonucleotide reductase. In vitro studies showed that M. dichloromethanicumalso has AdoCbl-independent ribonucleotide reductase. Under good aeration, exogenous AdoCbl had no effect on DNA biosynthesis, while hydroxyurea suppressed it. These data suggest that AdoCbl-independent ribonucleotide reductase, which is likely to be activated by oxygen, plays an important part in DNA biosynthesis when M. dichloromethanicum is cultured with good aeration, whereas AdoCbl-dependent ribonucleotide reductase is active under conditions of poor aeration. |
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| Keywords: | Methylobacterium dichloromethanicum ribonucleotide reductase vitamin B12 adenosylcobalamin DNA biosynthesis |
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