Self-assembled light-driven photosynthetic-respiratory electron transport chain hybrid proton pump

One of the fundamental biochemical reactions providing the foundation of life is photosynthesis occurring in plants and cyanobacteria. Photon energy is converted into stored chemical energy which flows through various metabolic processes that in the case of most aerobic organisms, terminates in the electron transport chain. In this study we demonstrate a synthetic hybrid photosynthetic-respiratory chain based on ruthenium(II)-terpyridine linked to cytochrome c and coupled with cytochrome c oxidase. Upon irradiation at an initial pH of 7.2, we observe proton pumping at a rate of ≈3.3 × 103 H+ per s across the polymer bilayer generating a gradient up to ΔpH ≈ 0.2. Remarkably, cytochrome c oxidase appears to have a greater than 50% native mitochondrial orientation in the polymersome membrane. Our photoactive hybrid electron-proton chain generates a proton gradient that can store chemical energy which is a step towards the development of a model artificial protocell.

[1]  P. Brzezinski,et al.  The inside pH determines rates of electron and proton transfer in vesicle-reconstituted cytochrome c oxidase. , 2007, Biochimica et biophysica acta.

[2]  Electron transfer across vesicle bilayers , 1991 .

[3]  F. Braet,et al.  Induced polymersome formation from a diblock PS-b-PAA polymer via encapsulation of positively charged proteins and peptides. , 2011, Chemical communications.

[4]  B. Giese,et al.  Electron transfer in peptides and proteins. , 2009, Chemical Society reviews.

[5]  Hermann Marsoner,et al.  Fluorimetric analysis , 1983 .

[6]  P. Thordarson,et al.  Optimising the synthesis, polymer membrane encapsulation and photoreduction performance of Ru(II)- and Ir(III)-bis(terpyridine) cytochrome c bioconjugates. , 2013, Organic & biomolecular chemistry.

[7]  pH-sensitive fluorescent dye as probe for proton uptake in photosynthetic reaction centers. , 2004, Bioelectrochemistry.

[8]  J. V. van Hest,et al.  Controlled shape transformation of polymersome stomatocytes. , 2011, Angewandte Chemie.

[9]  J. K. Hurst,et al.  Photoregulated transmembrane charge separation by linked spiropyran-anthraquinone molecules. , 2006, Journal of the American Chemical Society.

[10]  A. Eisenberg,et al.  Control of amphiphilic block copolymer morphologies using solution conditions , 2003, The European physical journal. E, Soft matter.

[11]  Cornelia G Palivan,et al.  Protein-polymer nanoreactors for medical applications. , 2012, Chemical Society reviews.

[12]  Pall Thordarson,et al.  Photoinduced reduction of catalytically and biologically active Ru(II)bisterpyridine-cytochrome c bioconjugates. , 2007, Chemical communications.

[13]  T. Tomizaki,et al.  Redox-coupled crystal structural changes in bovine heart cytochrome c oxidase. , 1998, Science.

[14]  P. Cullis,et al.  Influence of vesicle size and oxidase content on respiratory control in reconstituted cytochrome oxidase vesicles. , 1984, Biochemistry.

[15]  D. Bartel,et al.  Synthesizing life : Paths to unforeseeable science & technology , 2001 .

[16]  S. Matile,et al.  Rigid oligoperylenediimide rods: anion-pi slides with photosynthetic activity. , 2008, Angewandte Chemie.

[17]  M. Hope,et al.  Extrusion technique to generate liposomes of defined size. , 2003, Methods in enzymology.

[18]  Lifeng Zhang,et al.  Morphogenic Effect of Added Ions on Crew-Cut Aggregates of Polystyrene-b-poly(acrylic acid) Block Copolymers in Solutions , 1996 .

[19]  E. Damiano,et al.  Use of the pH sensitive fluorescence probe pyranine to monitor internal pH changes in Escherichia coli membrane vesicles , 1984, FEBS letters.

[20]  Thomas A. Moore,et al.  Conversion of light energy to proton potential in liposomes by artificial photosynthetic reaction centres , 1997, Nature.

[21]  Mathias Winterhalter,et al.  Nanoreactors based on (polymerized) ABA-triblock copolymer vesicles , 2000 .

[22]  P. Rich.  The molecular machinery of Keilin's respiratory chain. , 2003, Biochemical Society transactions.

[23]  S. Ichikawa,et al.  Enzymes inside lipid vesicles: preparation, reactivity and applications. , 2001, Biomolecular engineering.

[24]  Lifeng Zhang,et al.  Multiple Morphologies of "Crew-Cut" Aggregates of Polystyrene-b-poly(acrylic acid) Block Copolymers , 1995, Science.

[25]  Dennis E. Discher,et al.  Polymer vesicles : Materials science: Soft surfaces , 2002 .

[26]  Hyo-Jick Choi,et al.  Artificial organelle: ATP synthesis from cellular mimetic polymersomes. , 2005, Nano letters.

[27]  J. Lehn,et al.  Light-driven, carrier-mediated electron transfer across artificial membranes , 1977, Nature.

[28]  Sheshanath V. Bhosale,et al.  Photoproduction of Proton Gradients with π-Stacked Fluorophore Scaffolds in Lipid Bilayers , 2006, Science.

[29]  S. Ferguson-Miller,et al.  Heme/Copper Terminal Oxidases. , 1996, Chemical reviews.

[30]  Peter Lindblad,et al.  Biomimetic and microbial approaches to solar fuel generation. , 2009, Accounts of chemical research.

[31]  C. Hackenbrock,et al.  Cytochrome c oxidase from rat liver mitochondria: purification and characterization. , 1978, Biochemistry.

[32]  Thomas A. Moore,et al.  Light-driven production of ATP catalysed by F0F1-ATP synthase in an artificial photosynthetic membrane , 1998, Nature.

[33]  Jan C M van Hest,et al.  Positional assembly of enzymes in polymersome nanoreactors for cascade reactions. , 2007, Angewandte Chemie.

[34]  W. Leung,et al.  Synthesis and photophysical properties of new fluorinated benzo[c]xanthene dyes as intracellular pH indicators. , 2001, Bioorganic & medicinal chemistry letters.

[35]  Kensuke Kurihara,et al.  Self-reproduction of supramolecular giant vesicles combined with the amplification of encapsulated DNA. , 2011, Nature chemistry.

[36]  B. Valderrama,et al.  Oxidative stabilization of iso‐1‐cytochrome c by redox‐inspired protein engineering , 2006, FASEB journal : official publication of the Federation of American Societies for Experimental Biology.

[37]  K. Hellingwerf,et al.  Bacteriorhodopsin in liposomes. I. A description using irreversible thermodynamics. , 1979, Biochimica et biophysica acta.

[38]  M. Davies.  Singlet oxygen-mediated damage to proteins and its consequences. , 2003, Biochemical and biophysical research communications.

[39]  R. Nolte,et al.  Vesicles and polymerized vesicles from thiophene-containing rod-coil block copolymers. , 2003, Angewandte Chemie.

[40]  Michael F. Rubner,et al.  Influence of the Degree of Ionization on Weak Polyelectrolyte Multilayer Assembly , 2005 .