Improvement in the activity of recombinant CO dehydrogenase from Pantoea species YR343 using an accessory protein (CoxF)

Abstract

Carbon monoxide dehydrogenases (CODHs) are biocatalysts, converting carbon monoxide (CO) to carbon dioxide (CO2). Previous studies showed the aerobic CODHs can be applicable in various fields, since they have CO conversion in oxic condition. However, the application of aerobic CODHs was hampered because of their low activity in vitro. Recent study showed that the aerobic CODH obtained from Oligotropha carboxidovorans has several accessory proteins (coxBCDEFGHIK) expected to be required for the insertion of the MCD cofactor in their cognate organism. Our research group has studied the aerobic recombinant CODH from Pantoea species YR343 (PsCODH) in E.coli to be closed to E.coli in phylogenetic tree. However, PsCODH didn’t have enough activity when CODH was used for CO conversion. For the first time, we expressed recombinant CODH of Pantoea species YR343 (PsCODH) with an accessory protein (PscoxF) in E.coli as co-expression method. The recombinant PsCODH co-expressed with the accessory protein acquired much higher activity compared with that of PsCODH structural proteins (CoxLMS) only. In addition, we analyzed whether PscoxF affects metal incorporation into the CoxLMS. As a results, we showed that PsCODH affected Cu ion incorporation as analyzing the ICP-OES. The results demonstrate that co-expression of PscoxF with recombinant CODH leads to a higher activity, a promising strategy for producing high value-added substances using CO utilization system.