Influence of the fusion of two subunits of the F-420-non-reducing hydrogenase of Methanococcus voltae on its biochemical properties

In Methanococcus voltae, one of the two [NiFeSe] hydrogenases is unusual in that the large subunit is split into two subunits, each contributing two l igands to the [NiFe] center that catalyzes the heterolytic cleavage of the dihydrogen molecule. We have engineered a fusion of these two subunits. The resulting new enzyme showed no significant difference in hydrogen uptake a ctivity or in the Ni-C or Ni-L EPR spectra compared to the the wild-type en zyme, but exhibited a tenfold increase in both the K-m for hydrogen and the K-i for the competitive inhibitor carbon monoxide.