Photo-oxidation of tyrosine in a bio-engineered bacterioferritin ‘reaction centre’—A protein model for artificial photosynthesis
| Autor: | Thomas Wydrzynski, Paul N. Smith, Michael Cheah, Kastoori Hingorani, Spencer M. Whitney, Warwick Hillier, Ronald Pace, James W. Murray |
|---|---|
| Rok vydání: | 2014 |
| Předmět: |
Models
Molecular Photosynthetic reaction centre Photosystem II Bacterioferritin Photochemistry Stereochemistry Biophysics Metal Binding Site Protein Engineering 010402 general chemistry Polymerase Chain Reaction 7. Clean energy 01 natural sciences Biochemistry Electron transfer 03 medical and health sciences Bacterial Proteins Oxidoreductase Photosynthesis Tyrosine Artificial photosynthesis DNA Primers 030304 developmental biology chemistry.chemical_classification 0303 health sciences Base Sequence biology Chemistry Electron Spin Resonance Spectroscopy Protein engineering Cell Biology Cytochrome b Group 0104 chemical sciences Crystallography Ferritins biology.protein Tyrosine oxidation Oxidation-Reduction |
| Zdroj: | Biochimica et Biophysica Acta (BBA) - Bioenergetics. 1837(10):1821-1834 |
| ISSN: | 0005-2728 |
| DOI: | 10.1016/j.bbabio.2014.07.019 |
| Popis: | The photosynthetic reaction centre (RC) is central to the conversion of solar energy into chemical energy and is a model for bio-mimetic engineering approaches to this end. We describe bio-engineering of a Photosystem II (PSII) RC inspired peptide model, building on our earlier studies. A non-photosynthetic haem containing bacterioferritin (BFR) from Escherichia coli that expresses as a homodimer was used as a protein scaffold, incorporating redox-active cofactors mimicking those of PSII. Desirable properties include: a di-nuclear metal binding site which provides ligands for bivalent metals, a hydrophobic pocket at the dimer interface which can bind a photosensitive porphyrin and presence of tyrosine residues proximal to the bound cofactors, which can be utilised as efficient electron-tunnelling intermediates. Light-induced electron transfer from proximal tyrosine residues to the photo-oxidised ZnCe6(•+), in the modified BFR reconstituted with both ZnCe6 and Mn(II), is presented. Three site-specific tyrosine variants (Y25F, Y58F and Y45F) were made to localise the redox-active tyrosine in the engineered system. The results indicate that: presence of bound Mn(II) is necessary to observe tyrosine oxidation in all BFR variants; Y45 the most important tyrosine as an immediate electron donor to the oxidised ZnCe6(•+) and that Y25 and Y58 are both redox-active in this system, but appear to function interchangebaly. High-resolution (2.1Å) crystal structures of the tyrosine variants show that there are no mutation-induced effects on the overall 3-D structure of the protein. Small effects are observed in the Y45F variant. Here, the BFR-RC represents a protein model for artificial photosynthesis. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect