Expression of cytochrome c-553(CO) gene that complements the second subunit deficiency of membrane-bound alcohol dehydrogenase in Gluconobacter suboxydans subsp. α

Abstract

Cytochrome c-553 (CO) gene was subcloned onto a shuttle vector pGEA1 able to replicate in Gluconobacter suboxydans and Escherichia coli, forming pGEAC1. pGEAC1 transformed G. suboxydans subsp. α which has low ethanol oxidation activity because of a second subunit deficiency of membrane-bound alcohol dehydrogenase (ADH). The transformants harboring pGEAC1 expressed ethanol oxidation activity and produced material cross-reactive with anti-cytochrome c-553 (CO) antibody in the membrane. Furthermore, expression of cytochrome c-553 (CO) gene resulted in elevated levels of heme c and CO-reactive cytochrome c, complemented the deficiency of the second ADH subunit, and restored ethanol oxidase activity. We previously reported that cytochrome c-553 (CO) has significant amino acid sequence homology (60%) to the cytochrome subunit of ADH from Acetobacter aceti (Takeda, Y. et al., J. Ferment. Bioeng., 72, 1, 1991). Hence, cytochrome c-553 (CO) is the second subunit of ADH.