Designed azurins show lower reorganization free energies for intraprotein electron transfer
| Autor: | Israel Pecht, Yi Lu, Scot Wherland, Ole Farver, Nicholas M. Marshall |
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| Rok vydání: | 2013 |
| Předmět: |
Models
Molecular Multidisciplinary Coordination sphere Chemistry Electron Spin Resonance Spectroscopy Protein Engineering Photochemistry Electron transport chain Redox Recombinant Proteins Marcus theory Electron Transport Kinetics Electron transfer Azurin Intramolecular force Physical Sciences Pseudomonas aeruginosa Mutagenesis Site-Directed Thermodynamics Reactivity (chemistry) Disulfides Pulse Radiolysis Copper |
| Zdroj: | Proceedings of the National Academy of Sciences. 110:10536-10540 |
| ISSN: | 1091-6490 0027-8424 |
| DOI: | 10.1073/pnas.1215081110 |
| Popis: | Low reorganization free energies are necessary for fast electron transfer (ET) reactions. Hence, rational design of redox proteins with lower reorganization free energies has been a long-standing challenge, promising to yield a deeper understanding of the underlying principles of ET reactivity and to enable potential applications in different energy conversion systems. Herein we report studies of the intramolecular ET from pulse radiolytically produced disulfide radicals to Cu(II) in rationally designed azurin mutants. In these mutants, the copper coordination sphere has been fine-tuned to span a wide range of reduction potentials while leaving the metal binding site effectively undisrupted. We find that the reorganization free energies of ET within the mutants are indeed lower than that of WT azurin, increasing the intramolecular ET rate constants almost 10-fold: changes that are correlated with increased flexibility of their copper sites. Moreover, the lower reorganization free energy results in the ET rate constants reaching a maximum value at higher driving forces, as predicted by the Marcus theory. |
| Databáze: | OpenAIRE |
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