Аннотация:Formate dehydrogenase (EC 1.2.1.2, FDH) catalyzes a reaction of hydride ion transfer from substrate (formate) to nicotinamide ring of coenzyme NAD(P)+. The majority of FDHs have a high specificity to coenzyme NAD+ and they are used for the regeneration of NADH in processes of chiral compounds synthesis. It is known that there is the only one wild-type of FDH which is more specific to NADP+ then to NAD+. Nowadays NADPH is used in lots of important processes of optically active compounds synthesis. However, such processes are not widely used in industry due to an absence of FDH with high specific activity with NADP+, which can be successfully used for NADPH regeneration. Therefore an obtaining of NADP+-specific FDH is significant and actual problem.
It is remarkable that coenzyme is binding in the specific site and Asp221 residue plays a very important role in high activity with NADP+. Amino acid replacement of negatively charged Asp221 to some none-charged residue may eliminate repulsion between carboxyl group of Asp221 and 2'-phosphate group of NADP+ and consequently specific activity with NADP+ would increase. Such preposition was confirmed on bacterial FDH from Burkholderia stabilis and Pseudomonas sp. 101.
Previously in our laboratory mutant bacterial NADP+-dependent FDH from Pseudomonas sp. 101 which is called PseFDH D221A was obtained. In the present work the engineering of coenzyme specificity experiments were continued and the new double mutant PseFDH A198G/D221Q was obtained. Kinetic parameters of mutants in reaction with NAD+ and NADP+ were determined and thermal stability was investigated. It was shown that both mutant enzymes had a high specificity to NADP+. The double mutant PseFDH A198G/D221Q has the highest catalytic efficiency with NADP+ among all known NADP+-specific FDH.
This work was supported by Russian Foundation for Basic Research (grants 11-04-00920-а and 12-04-31740-mol a).