Construction and characterization of flavin adenine dinucleotide glucose dehydrogenase complex harboring a truncated electron transfer subunit

FADGDH complex harboring a truncated electron transfer subunit composed of only heme 3 was constructed. A truncated electron transfer subunit thus, the designed trβ subunit was expressed as a soluble and functional heme c molecule and formed a complex with a γα catalytic complex. The formed FADGDH complex showed inter-molecular electron transfer from the FAD to the trβ subunit and from the trβ subunit to an external electron acceptor and showed electron transfer subunit-mediated characteristic dye-mediated dehydrogenase activity with a Ru complex. Moreover, the FADGDH complex harboring the trβ subunit showed DET activity toward the electrode. Spectroelectrochemical observations revealed that the trβ subunit possessed a lower formal potential than that of any of the 3 hemes existing in the whole electron transfer subunit.262