Part:BBa_K1373000

This part encodes NAD synthetase

Open reading frame of nadE

Intracellular redox state of electricity active cells (EAC) is one of the most important physiological traits of extracellular electron transfer efficiency. In particular, the NAD⁺(H) pool size plays a central role of most metabolic pathways. By overexpressing the NAD synthetase, encoded be gene nadE and catalyzes the final step in de novo synthesis and salvage pathway of NAD biosynthesis (Fig. 1), the NAD+ level is increased thereby up-regulating genes whose products catalyze NADH synthesis. Therefore the augmented pool size of NAD⁺(H) result in promotion of NADH(the carrier of electrons)level, leading to high generation of intracellular releasable electrons and better electricity performance of EAC. ^[1]

Fig. 1 De novo synthesis and salvage pathway of NAD biosynthesis.

===Informational Contribution=== Group: iGEM21_NU_Kazakhstan Author: Arsen Orazbek iGEM21_NU_Kazakhstan team also worked with nadE genes as iGEM14_SCAU-China did. However, our nadE gene was extracted from Pseudomonas putida, thus, there are some differences in nucleotide sequence (https://parts.igem.org/Part:BBa_K4083004). Nonetheless, the main function of NAD synthethase expressed from nadE is mostly universal for different organisms. Therefore, our team considered to contribute the informational data of NAD/NADH importance. The NAD+ is important for metabolism in organisms. NAD+ can reduce into NADH during cell digestion like glucolysis or Krebs cycle. Thus, more available NAD+ can lead to faster substrate catabolism. Moreover, NADH interacts with the electron transport chain where it releases one electron and one proton. As an electron moves, more protons exit the bacterial membrane which increases the proton gradient. Finally, to reach equilibrium, protons enter the cell by ATP synthase, and one proton can generate up to 3 ATP molecules this way. Thus, one NADH that releases one proton can generate 3 ATP molecules. [1] Reference: [1]Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K., & Walter, P. (2002). Molecular biology of the cell. New York: Garland Science.

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