Mossbauer and EPR Study of the Ni-Activated α-Subunit of Carbon Monoxide Dehydrogenase from Clostridium thermoaceticum

摘要

The A-center of carbon monoxide dehydrogenase (CODH) resides in the enzyme's α-subunit and is responsible for the acetyl-CoA synthase activity. The center comprises a Ni site and an iron-sulfur cluster. We have isolated the α-subunit using both continuous and discontinuous electrophoresis methods. When incubated with CO, samples prepared using continuous gels attain the A_red-CO state that exhibits an S=1/2 EPR feature (g= 2.048, 2.046, 2.021) similar to the so-called NiFeC signal of native CODH.