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Published December 2010 | public
Conference Paper

Electron tunneling through mutant azurins on mixed SAM gold electrodes

Abstract

We are investigating interfacial electron transfer rates of P. aeruginosa azurin and its mutants using electrochem. at 1:1 CH3(CH2)nSH:HO(CH2)nSH mixed-SAM gold electrodes. We have examd. interfacial electron transfer rates of mutant azurins in which asparagine-47 was replaced by alanine, aspartic acid, lysine, arginine, leucine, threonine, serine, and glutamine. The N47D mutant on a mixed SAM exhibited a well-defined electrochem. response; N47T and N47S gave a weak signal; but the other 5 mutants showed no response. It is likely that the N47 side-chain carbonyl interacts with the mixed SAM surface, providing a very favorable electron tunneling pathway to the copper via an N47-C112 hydrogen bond. We also have examd. interfacial electron transfer rates of M121X mutant azurins. The ET rates for M121E are 2 orders of magnitude smaller; those for M121Q are almost 1 order of magnitude smaller; and those for the M121L protein are similar to those of wild-type azurin at pH 7. In addn., we have found that type zero azurins have higher ET rates than those of type 2 proteins (rates for C112D are 3 orders of magnitude smaller; those for type zero C112D/M121X (X=L and I) are 2 orders of magnitude smaller than wild-type at pH 7).

Additional Information

© 2012 American Chemical Society.

Additional details

Created:
August 19, 2023
Modified:
October 18, 2023