Coenzyme engineering of a hyperthermophilic 6-phosphogluconate dehydrogenase from NADP+ to NAD+ with its application to biobatteries
- Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)
- Cell Free Bioinnovations Inc., Blacksburg, VA (United States); Chinese Academy of Sciences, Tianjin (China)
- Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Cell Free Bioinnovations Inc., Blacksburg, VA (United States); Chinese Academy of Sciences, Tianjin (China)
Engineering the coenzyme specificity of redox enzymes plays an important role in metabolic engineering, synthetic biology, and biocatalysis, but it has rarely been applied to bioelectrochemistry. Here we develop a rational design strategy to change the coenzyme specificity of 6-phosphogluconate dehydrogenase (6PGDH) from a hyperthermophilic bacterium Thermotoga maritima from its natural coenzyme NADP+ to NAD+. Through amino acid-sequence alignment of NADP+- and NAD+-preferred 6PGDH enzymes and computer-aided substrate-coenzyme docking, the key amino acid residues responsible for binding the phosphate group of NADP+ were identified. Four mutants were obtained via site-directed mutagenesis. The best mutant N32E/R33I/T34I exhibited a ~6.4 × 104-fold reversal of the coenzyme selectivity from NADP+ to NAD+. The maximum power density and current density of the biobattery catalyzed by the mutant were 0.135 mW cm-2 and 0.255 mA cm-2, ~25% higher than those obtained from the wide-type 6PGDH-based biobattery at the room temperature. By using this 6PGDH mutant, the optimal temperature of running the biobattery was as high as 65 °C, leading to a high power density of 1.75 mW cm-2. As a result, this study demonstrates coenzyme engineering of a hyperthermophilic 6PGDH and its application to high-temperature biobatteries.
- Research Organization:
- Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE), Sustainable Transportation Office. Bioenergy Technologies Office (BETO)
- Grant/Contract Number:
- EE0006968
- OSTI ID:
- 1363908
- Journal Information:
- Scientific Reports, Vol. 6, Issue 1; ISSN 2045-2322
- Publisher:
- Nature Publishing GroupCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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