We have employed a novel recombinant azurin mutant where the cysteine residues 3 and 26 forming the internal disulfide bridge were replaced by alanines and a cysteine replaced the native alanine 42, thus leading to an azurin dimer linked via the disulfide formed between these residues and at a site closer to the copper center. An intramolecular electron transfer has been induced between the disulfide radical ion produced by pulse radiolytic reducing radicals and the Cu(II) ion. Analysis of this intramolecular long-range electron transfer (LRET) rates and their temperature dependence resolves a clear difference in the nature of this process as compared to that occurring in earlier-examined azurins inasmuch as the induced LRET proceeds along a shorter and structurally distinct part of the protein. Still, we demonstrate here that the results do fit the accepted model of how the heterogeneous matrix in a folded polypeptide mediates long-range electronic coupling.