... assigned to the Fe atom and the Ni atom [6,32].It has been hypothesized that these two CN–groupsmay shield the active site from O2attack by steric hin-drance [32,33]. The Ni-bound CN–seems to ... HoxBC, of R. eutropha was shown to be verysimilar to that of standard hydrogenases, with a Featom liganded by 1 CO and 2 CN–[16], and the bindingof an hydride to Ni and Fe after H2reduction ... saturation, and the vessel was closed. Then3 lg purified wild-type or mutated HupUV proteins wereintroduced into the vessel, and the changes in D2,HDand H2were monitored by scanning masses 4, 3 and...