Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5371910 | Biophysical Chemistry | 2008 | 7 Pages |
In several classes of proteins the redox center provides an additional intrinsic biophysical probe that could be used to study the protein structure and function. In present report reorganization energy (λ, as a parameter describing electron transfer properties) was used to study the protein structural changes around the heme prosthetic group in cytochrome c (cyt c). We attempted to monitor the value of this parameter upon the unfolding process of cyt c by urea, during which it was increased sigmoidally from about 0.52 to 0.82 eV for native and unfold protein, respectively. Results indicate that by structural changes in the heme site, λ provides a complementary tool for following the unfolding process. Assuming a reversible two-state model for cyt c unfolding, ÎGH2O, Cm and m values were determined to be 8.32 ± 0.7 kcal molâ 1, 1.53 ±0.19 kcalmolâ 1Mâ 1 and 5.03 M, respectively.