4cvp
Structure of ApobacterioferritinStructure of Apobacterioferritin
Structural highlights
Function[BFR_ECOL6] Iron-storage protein, whose ferroxidase center binds Fe(2+) ions, oxidizes them by dioxygen to Fe(3+), and participates in the subsequent Fe(3+) oxide mineral core formation within the central cavity of the protein complex (By similarity). Publication Abstract from PubMedThe 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 class II 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 MnII, 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 MnII 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 (2.1A) 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. Photo-oxidation of tyrosine in a bio-engineered bacterioferritin 'reaction centre'-A protein model for artificial photosynthesis.,Hingorani K, Pace R, Whitney S, Murray JW, Smith P, Cheah MH, Wydrzynski T, Hillier W Biochim Biophys Acta. 2014 Aug 5. pii: S0005-2728(14)00557-X. doi:, 10.1016/j.bbabio.2014.07.019. PMID:25107631[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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