Designing photosystem II: molecular engineering of photo-catalytic proteins

Conlan, Brendon

doi:10.1007/s11120-008-9355-5

Cited by 19 publications

(14 citation statements)

References 122 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…PSII performs linear electron transfer from H 2 O to the secondary acceptor, Q B (22). The redox active components from Y Z to Q B are embedded within the D1 and D2 proteins, while the oxygen evolving center (OEC) is bound to the luminal face of PSII (Fig.…”

Section: Resultsmentioning

confidence: 99%

Engineering of an alternative electron transfer path in photosystem II

Larom

Salama

Schuster

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

The initial steps of oxygenic photosynthetic electron transfer occur within photosystem II, an intricate pigment/protein transmembrane complex. Light-driven electron transfer occurs within a multistep pathway that is efficiently insulated from competing electron transfer pathways. The heart of the electron transfer system, composed of six linearly coupled redox active cofactors that enable electron transfer from water to the secondary quinone acceptor Q B , is mainly embedded within two proteins called D1 and D2. We have identified a site in silico, poised in the vicinity of the Q A intermediate quinone acceptor, which could serve as a potential binding site for redox active proteins. Here we show that modification of Lysine 238 of the D1 protein to glutamic acid (Glu) in the cyanobacterium Synechocystis sp. PCC 6803, results in a strain that grows photautotrophically. The Glu thylakoid membranes are able to perform light-dependent reduction of exogenous cytochrome c with water as the electron donor. Cytochrome c photoreduction by the Glu mutant was also shown to significantly protect the D1 protein from photodamage when isolated thylakoid membranes were illuminated. We have therefore engineered a novel electron transfer pathway from water to a soluble protein electron carrier without harming the normal function of photosystem II. cyanobacteria | energy conversion | proinhibition | photosynthesis | protein engineering P hotosynthesis is the major source of useful chemical energy in the biosphere. All photosynthetic processes require efficient electron transfer (ET) pathways that are utilized for proton gradient formation (to be used for the production of ATP) and/or accumulation of reducing equivalents (1, 2). Light energy, absorbed by light-harvesting antenna complexes, is transferred to photochemical reaction centers (RC), initiating charge separation in specific chlorophyll molecules bound to the RC proteins. Following charge separation, electrons are transferred sequentially to a series of acceptor molecules, each with a redox potential determined by its immediate environment (3, 4). The source of electron replenishment differs according to the reaction center type. For instance in purple non-sulfur bacteria, electrons are cycled back to the oxidized reaction center by a soluble cytochrome c (cyt c) type protein (5, 6). Oxygenic photosynthetic organisms (cyanobacteria, red and green algae and plants) contain two photosystems: photosystem I (PSI) and photosystem II (PSII) that work linearly (1, 7), and the source of electrons is water. One common facet of all ET pathways is the requirement for insulation of the redox active cofactors from potentially reducing/oxidizing molecules within the RC or in the surrounding media. Insulation provides the system with maximal ET rates and efficiencies and also prevents damage to the RC.PSII has a redox potential of up to 1.2 V (8, 9), required to abstract electrons from water (Fig. 1A). The photoexcited P 680 reaction center chlorophyll a primary donor transfers electron...

show abstract

Section: Resultsmentioning

confidence: 99%

Engineering of an alternative electron transfer path in photosystem II

Larom

Salama

Schuster

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…Bacterioferritin contains a diiron-binding site that links the four helices of the protein together using four glutamate and two histidine residues (Dautant et al 1998) and acts as a ferroxidase, in which Fe II is oxidized to Fe 2 III by O 2 (Lebrun et al 1995). The Fe ions can be substituted with Mn(II) as was done in the original crystal structure of BFR (Dautant et al 1998) and verified by EPR spectroscopy and isothermal titration calorimetry (Conlan 2008).…”

Section: Bio-engineering and Directed Evolution Of Photosystem IImentioning

confidence: 93%

“…ZnCe 6 is utilized as a photoactive pigment because of its strong Q y absorption band in the red (*638 nm), and high estimated oxidation potential of approximately ?1.1 eV (Hay et al 2004). Electron transfer from ZnCe 6 to a quinone has been demonstrated when bound to both de novo peptides and b-type cytochromes (Conlan 2008;Hay and Wydrzynski 2005;Mennenga et al 2006;Razeghifard and Wydrzynski 2003). Another cofactor found in biology which is capable of photo-initiated electron transfer within proteins is that of flavins.…”

Section: Bio-engineering and Directed Evolution Of Photosystem IImentioning

confidence: 99%

See 1 more Smart Citation

The evolution of Photosystem II: insights into the past and future

et al. 2010

Self Cite

View full text Add to dashboard Cite

This article attempts to address the molecular origin of Photosystem II (PSII), the central component in oxygenic photosynthesis. It discusses the possible evolution of the relevant cofactors needed for splitting water into molecular O2 with respect to the following functional domains in PSII: the reaction center (RC), the oxygen evolving complex (OEC), and the manganese stabilizing protein (MSP). Possible ancestral sources of the relevant cofactors are considered, as are scenarios of how these components may have been brought together to produce the intermediate steps in the evolution of PSII. Most importantly, the driving forces that maintained these intermediates for continued adaptation are considered. We then apply our understanding of the evolution of PSII to the bioengineering of a water oxidizing catalyst for utilization of solar energy.

show abstract

“…Thus, it is expected that the fixation of ZnP and Ru 3 O in the three-dimensional Mb crystal space allows 1) the close approach of MV molecules to ZnP and Ru 3 O, 2) the small reorganization energy of the Ru 3 O cluster, and 3) the spatial separation of ZnPC + and Ru 3 O 0 species. [30] The crystal structure of ZnMb/Ru 3 O reveals that ZnP and Ru 3 O are site-specifically located over intra-and interprotein contacts with separation distances of 21-23 (Figure 3 a). On the other hand, although the unambiguous positions of MV molecules were not determined by X-ray crystal structure analysis, positively charged MV molecules are expect to diffuse around ZnP and Ru 3 O in the crystal because the negatively charged binding sites of ZnP and Ru 3 O govern the diffusion of MV molecules in the crystal channels, as reported for the Cl À ion/HEWL crystal system (Figure 3 b).…”

mentioning

confidence: 99%

Post‐Crystal Engineering of Zinc‐Substituted Myoglobin to Construct a Long‐Lived Photoinduced Charge‐Separation System

et al. 2011

View full text Add to dashboard Cite

Photoinduced electron transfer (ET) in native photosynthesis reactions is efficiently achieved by the accumulation of different types of redox cofactors within protein assemblies immobilized in cell membranes. [1][2][3] The precise arrangement of each cofactor in the molecular spaces enables them to retain the long-lived charge-separated state, which promotes multistep reactions in biological systems. To elucidate the mechanism of the biological ET reactions and to develop light energy conversion systems, artificial ET proteins have been constructed using de novo proteins, chemical modification of native cofactors, photocatalytic reaction centers engineered into protein assemblies, and design of synthetic metal complexes immobilized in protein-protein ET systems. [4][5][6][7][8][9][10][11][12] The reported systems have provided insights into control of ET rates in terms of the distance between donors and acceptors, hydrogen-bonding interactions, reorganization energy of cofactors, and other factors. [4][5][6][7][8][9][10][11][12] Control of the dense accumulation of the different redox cofactors observed in natural photosystems required to achieve long-lived charge-separated state has caused difficulties in efforts to duplicate this process using artificial protein systems in solution. [13] Thus, the design of novel protein frameworks that allow construction of a dense array of various cofactors is a worthwhile goal.Protein crystals can be regarded as excellent candidates for the development of artificial ET reaction systems because the crystal lattices are expected to allow different types of cofactors to be arranged in three-dimensional frameworks that mimic the native ET systems. ET reactions in single protein crystals have been investigated for the dependence of long-range ET on the structures and orientations of redox centers within proteins. [14][15][16] Gray et al. constructed photochemically-initiated protein-protein ET reactions in protein crystals containing zinc-substituted cytochrome c peroxidase or ruthenium-modified azurin. [14][15][16] Moreover, protein crystals provide nanosized spaces for the fixation of metal ions, metal complexes, and the diffusion of organic molecules. [17][18][19][20][21][22] For instance, accumulation of metal ions and metal complexes in a protein crystal lattice spaces was accomplished simply by soaking of the crystals in a solution containing their precursors. [17][18][19] Anisotropic diffusion of small molecules in hen egg-white lysozyme (HEWL) crystals has been investigated by experimental and simulation approaches. [21,22] The results suggest that these features are governed by steric repulsion and electrostatic interaction induced by amino acid residues located on the internal surface of the crystal lattices. Thus, if we can precisely arrange donor and acceptor molecules and mediators in protein crystals, it is expected that the novel three-dimensional framework will allow us to achieve a longlived charge-separated state.Herein, we construct an artificial long-lived ph...

show abstract

Designing photosystem II: molecular engineering of photo-catalytic proteins

Cited by 19 publications

References 122 publications

Engineering of an alternative electron transfer path in photosystem II

Engineering of an alternative electron transfer path in photosystem II

The evolution of Photosystem II: insights into the past and future

Post‐Crystal Engineering of Zinc‐Substituted Myoglobin to Construct a Long‐Lived Photoinduced Charge‐Separation System

Contact Info

Product

Resources

About