FIGURE 10.
Surface representation of the FixK2(C183S)-His6 protein bound to DNA. The two monomers are shown in red and blue. Ser-183 is surface-exposed and in close proximity to the DNA. In the wild-type protein, oxidation of Cys-183 at this position most likely inactivates the protein through steric hindrance of DNA binding or electrostatic repulsion of the DNA. Met-177 is highlighted as well, being the only one of eight methionines that is located on the surface of the protein. Met-177 is accessible to oxidation, but its oxidation does not influence protein activity.