Cytochrome C Mutants with Enhanced Capabilities in Multi Layer Arrangements
Based on the hypothesis, that the electron transfer happens via hopping between the heme-centers which are embedded in a protein-pocket that is mainly positively charged at neutral pH, we tried to engineer human cytochrome c mutants with increased electron self exchange rates. By replacing some of the positively charged surface lysines around the heme pocket with uncharged alanines via site directed mutagenesis, repulsion between cytochrome c molecules should be decreased and ease the charge transfer.
Six different mutants have been designed, expressed and evaluated. The electrochemical properties of the cytochrome c mutants have been analyzed by cyclic voltammetry at self assembling mono layers (SAMs) of 11-mercapto-1-undecanol (MU) and 11-mercapto-1-undecanoic acid (MUA) on gold. In a second step cytochrome c mutant multi layers have been prepared and analyzed with respect to different rates of the potential sweep in order to elucidate how the systems can follow the driving force.