| Budget Amount *help |
¥5,070,000 (Direct Cost: ¥3,900,000、Indirect Cost: ¥1,170,000)
Fiscal Year 2016: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2015: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Fiscal Year 2014: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
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| Outline of Final Research Achievements |
Nicotinamide cofactors are involved in a wide variety of enzymatic redox reactions and ubiquitously present in all organisms. Although thermophiles also use these cofactors, nicotinamide cofactors are readily degraded at high temperatures where thermophiles preferably grow. To address this discrepancy, we have characterized enzymes composing the salvage synthesis of NAD+ in a thermophilic bacterium, Thermus thermophilus, and evaluated their importance in the bacterial growth at high temperatures. As a result, we newly identified the gene encoding nicotinamidase, which is engaged in the first step of the salvage synthesis of NAD+, of T. thermophilus. Disruption of this gene resulted in a marked decrease in the bacterial growth at 80°C. In addition, we reconstituted the NAD+ salvage pathway in vitro using thermophilic enzymes. In the presence of reconstituted pathway, NAD+ concentration could be kept almost constant at 60°C for 15 h.
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