(A) Calculated electron transfer pathway from the disulfide bond to the copper site in Az mutants. Residues involved in electron transfer are in red. (B) Logarithm of the electron transfer rate constants as a function of the driving force of the reaction (dots) and the theoretically calculated bell-shaped curve. Mutants: 1, Phe114Pro/Met121Gln; 2, Phe114Pro; 3, Asn47Ser/Phe114Asn; 4, Asn47Ser/Met121Leu; 5, Phe114Asn/ Met121Leu; 6, Asn47Ser/Phe114Asn/Met121Leu. Reproduced with permission from ref 393. Copyright 2013 National Academy of Sciences.