Team:TMU-Tokyo/Project device3

Device3 is composed of the strongest constitutive promoter (BBa_J23100), the srtongest RBS (BBa_B0034) and fdh4AB formate dehydrogenase gene from Methylobacterium extorquens.

Formate dehydrogenase in Methylobacterium extorquens decomposes formate to water and corbon dioxide. This enzyme is a part of the methanol metabolism pathway.

FDH4AB is composed of 2 subunits, the large subunit FDH4A and the small subunit FDH4B. In Methylobacterium extorquens, some similar enzymes, FDH1, FDH2, FDH3 exist. The reason we selected FDH4AB from some kinds of FDHs is that FDH4AB was the core enzyme in FDHs. In other wards, FDH4AB works even without other FDHs, but other FDHs don't work without FDH4AB.

Escherichia coli has similar function gene of this gene, named hycBCDEFG and fdhF, the former genes cord hydrogenase Ⅲ and the latter gene cords FDH-F subunit that binds to former. The complex is called formate dehydrogenase-H (FHD-H).

First, we planned to use these genes, but they have too long length to insert high copy plasmid and produces hydrogen instead of water. Therefore, we selected fdh4AB in Methylobacterium extorquens.

■About fdh4AB in Methylobacterium extorquens
Ludmila Chistoserdova, Gregory J. Crowther, Julia A. Vorholt, Elizabeth Skovran, Jean-Charles Portais, and Mary E. Lidstrom. 2007. "Identification of a Fourth Formate Dehydrogenase in Methylobacterium extorquens AM1 and Confirmation of the Essential Role of Formate Oxidation in Methylotrophy."
[PubMed]






■fig.1
A) Growth of Methylobacterium extorquens wild type, the triple-FDH deletion mutant, and the quadruple deletion mutants FDH4A and FDH4B on medium including methanol.
B) Formate accumulation in the medium with same samples.

Methylobacterium extorquens has methanol dehydrogenase, so methanol is naturally changed to formaldehyde.













■Original formate dehydrogenase in E. coli
"Enzyme: formate dehydrogenase H" [EcoCyc]