1
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Yakovlev AG, Taisova AS. Downhill excitation energy flow in reaction centers of purple bacteria Rhodospirillum rubrum G9. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2024; 1865:149499. [PMID: 39069149 DOI: 10.1016/j.bbabio.2024.149499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2024] [Revised: 07/24/2024] [Accepted: 07/24/2024] [Indexed: 07/30/2024]
Abstract
Using femtosecond differential spectroscopy, excitation energy transfer in reaction centers (RCs) of the carotenoidless strain of purple bacteria Rhodospirillum rubrum G9 was studied at room temperature. Excitation and probing of the Qy, Qx and Soret absorption bands of the RCs were carried out by pulses with duration of 25-30 fs. Modeling of ΔA (light - dark) kinetics made it possible to estimate the characteristic time of various stages of excitation energy transformation. It is shown that the dynamics of the downhill energy flow in the RCs is determined both by the internal energy conversion Soret→ Qx → Qy in each cofactor and by the energy transfer H* → B* → P* (H - bacteriopheophytin, B - bacteriochlorophyll a, P - bacteriochlorophyll a dimer) between cofactors. The transfer of energy between the upper excited levels (Soret and Qx) of the cofactors accelerates its arrival to the lower exciton level of the P, from where charge separation begins. It turned out that all conversion and energy transfer processes occur within 40-160 fs: the conversion Soret → Qx occurs in 40-50 fs, the conversion Qx → Qy occurs in 100-140 fs, the transfer H* → B* has a time constant of 80-120 fs, and the transfer B* → P* has a time constant of 130-160 fs. The rate of energy transfer between the upper excited levels is close to the rate of transfer between Qy levels.
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Affiliation(s)
- Andrei G Yakovlev
- Lomonosov Moscow State University, Belozersky Institute of Physico-Chemical Biology, Leninskie Gory, 119991 Moscow, Russian Federation.
| | - Alexandra S Taisova
- Lomonosov Moscow State University, Belozersky Institute of Physico-Chemical Biology, Leninskie Gory, 119991 Moscow, Russian Federation
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2
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Noji T, Saito K, Ishikita H. Absence of a link between stabilized charge-separated state and structural changes proposed from crystal structures of a photosynthetic reaction center. Commun Chem 2024; 7:192. [PMID: 39215069 PMCID: PMC11364808 DOI: 10.1038/s42004-024-01281-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2024] [Accepted: 08/22/2024] [Indexed: 09/04/2024] Open
Abstract
Structural differences between illuminated and unilluminated crystal structures led to the proposal that the charge-separated state was stabilized by structural changes in its membrane extrinsic protein subunit H in a bacterial photosynthetic reaction center [Katona, G. et al. Nat. Struct. Mol. Biol. 2005, 12, 630-631]. Here, we explored the proposal by titrating all titratable sites and calculating the redox potential (Em) values in these crystal structures. Contrary to the expected charge-separated states, Em for quinone, Em(QA/QA•-), is even lower in the proposed charge-separated structure than in the ground-state structure. The subunit-H residues, which were proposed to exhibit electron-density changes in the two crystal structures, contribute to an Em(QA/QA•-) difference of only <0.5 mV. Furthermore, the protonation states of the titratable residues in the entire reaction center are practically identical in the two structures. These findings indicate that the proposed structural differences are irrelevant to explaining the significant prolongation of the charge-separated-state lifetime.
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Affiliation(s)
- Tomoyasu Noji
- Department of Applied Chemistry, The University of Tokyo, Bunkyo-ku, Tokyo, 1, Japan
- Research Center for Advanced Science and Technology, The University of Tokyo, Meguro-ku, Tokyo, Japan
| | - Keisuke Saito
- Department of Applied Chemistry, The University of Tokyo, Bunkyo-ku, Tokyo, 1, Japan
- Research Center for Advanced Science and Technology, The University of Tokyo, Meguro-ku, Tokyo, Japan
| | - Hiroshi Ishikita
- Department of Applied Chemistry, The University of Tokyo, Bunkyo-ku, Tokyo, 1, Japan.
- Research Center for Advanced Science and Technology, The University of Tokyo, Meguro-ku, Tokyo, Japan.
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3
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Faries KM, Hanson DK, Buhrmaster JC, Hippleheuser S, Tira GA, Wyllie RM, Kohout CE, Magdaong NCM, Holten D, Laible PD, Kirmaier C. Two pathways to understanding electron transfer in reaction centers from photosynthetic bacteria: A comparison of Rhodobacter sphaeroides and Rhodobacter capsulatus mutants. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2024; 1865:149047. [PMID: 38692451 DOI: 10.1016/j.bbabio.2024.149047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 04/23/2024] [Accepted: 04/24/2024] [Indexed: 05/03/2024]
Abstract
The rates, yields, mechanisms and directionality of electron transfer (ET) are explored in twelve pairs of Rhodobacter (R.) sphaeroides and R. capsulatus mutant RCs designed to defeat ET from the excited primary donor (P*) to the A-side cofactors and re-direct ET to the normally inactive mirror-image B-side cofactors. In general, the R. sphaeroides variants have larger P+HB- yields (up to ∼90%) than their R. capsulatus analogs (up to ∼60%), where HB is the B-side bacteriopheophytin. Substitution of Tyr for Phe at L-polypeptide position L181 near BB primarily increases the contribution of fast P* → P+BB- → P+HB- two-step ET, where BB is the "bridging" B-side bacteriochlorophyll. The second step (∼6-8 ps) is slower than the first (∼3-4 ps), unlike A-side two-step ET (P* → P+BA- → P+HA-) where the second step (∼1 ps) is faster than the first (∼3-4 ps) in the native RC. Substitutions near HB, at L185 (Leu, Trp or Arg) and at M-polypeptide site M133/131 (Thr, Val or Glu), strongly affect the contribution of slower (20-50 ps) P* → P+HB- one-step superexchange ET. Both ET mechanisms are effective in directing electrons "the wrong way" to HB and both compete with internal conversion of P* to the ground state (∼200 ps) and ET to the A-side cofactors. Collectively, the work demonstrates cooperative amino-acid control of rates, yields and mechanisms of ET in bacterial RCs and how A- vs. B-side charge separation can be tuned in both species.
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Affiliation(s)
- Kaitlyn M Faries
- Department of Chemistry, Washington University, St. Louis, MO 63130, United States of America
| | - Deborah K Hanson
- Biosciences Division, Argonne National Laboratory, Lemont, IL 60439, United States of America
| | - James C Buhrmaster
- Biosciences Division, Argonne National Laboratory, Lemont, IL 60439, United States of America
| | - Stephen Hippleheuser
- Biosciences Division, Argonne National Laboratory, Lemont, IL 60439, United States of America
| | - Gregory A Tira
- Biosciences Division, Argonne National Laboratory, Lemont, IL 60439, United States of America
| | - Ryan M Wyllie
- Biosciences Division, Argonne National Laboratory, Lemont, IL 60439, United States of America
| | - Claire E Kohout
- Biosciences Division, Argonne National Laboratory, Lemont, IL 60439, United States of America
| | - Nikki Cecil M Magdaong
- Department of Chemistry, Washington University, St. Louis, MO 63130, United States of America
| | - Dewey Holten
- Department of Chemistry, Washington University, St. Louis, MO 63130, United States of America
| | - Philip D Laible
- Biosciences Division, Argonne National Laboratory, Lemont, IL 60439, United States of America
| | - Christine Kirmaier
- Department of Chemistry, Washington University, St. Louis, MO 63130, United States of America.
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4
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Begam K, Aksu H, Dunietz BD. Antioxidative Triplet Excitation Energy Transfer in Bacterial Reaction Center Using a Screened Range Separated Hybrid Functional. J Phys Chem B 2024. [PMID: 38687467 DOI: 10.1021/acs.jpcb.3c08501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2024]
Abstract
Excess energy absorbed by photosystems (PSs) can result in photoinduced oxidative damage. Transfer of such energy within the core pigments of the reaction center in the form of triplet excitation is important in regulating and preserving the functionality of PSs. In the bacterial reaction center (BRC), the special pair (P) is understood to act as the electron donor in a photoinduced charge transfer process, triggering the charge separation process through the photoactive branch A pigments that experience a higher polarizing environment. At this work, triplet excitation energy transfer (TEET) in BRC is studied using a computational perspective to gain insights into the roles of the dielectric environment and interpigment orientations. We find in agreement with experimental observations that TEET proceeds through branch B. The TEET process toward branch B pigment is found to be significantly faster than the hypothetical process proceeding through branch A pigments with ps and ms time scales, respectively. Our calculations find that conformational differences play a major role in this branch asymmetry in TEET, where the dielectric environment asymmetry plays only a secondary role in directing the TEET to proceed through branch B. We also address TEET processes asserting the role of carotenoid as the final triplet energy acceptor and in a mutant form, where the branch pigments adjacent to P are replaced by bacteriopheophytins. The necessary electronic excitation energies and electronic state couplings are calculated by the recently developed polarization-consistent framework combining a screened range-separated hybrid functional and a polarizable continuum mode. The polarization-consistent potential energy surfaces are used to parametrize the quantum mechanical approach, implementing Fermi's golden rule expression of the TEET rate calculations.
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Affiliation(s)
- Khadiza Begam
- Department of Physics, Kent State University, Kent, Ohio 44242, United States
| | - Huseyin Aksu
- Department of Physics, Faculty of Science at Canakkale Onsekiz Mart University, Canakkale 17100, Turkey
| | - Barry D Dunietz
- Department of Chemistry and Biochemistry, Kent State University, Kent, Ohio 44242, United States
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5
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Yakovlev AG, Taisova AS. Quenching of bacteriochlorophyll a triplet state by carotenoids in the chlorosome baseplate of green bacterium Chloroflexus aurantiacus. Phys Chem Chem Phys 2024; 26:8815-8823. [PMID: 38421198 DOI: 10.1039/d4cp00287c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2024]
Abstract
To capture weak light fluxes, green photosynthetic bacteria have unique structures - chlorosomes, consisting of 104-5 molecules of bacteriochlorophyll (BChl) c, d, e. Chlorosomes are attached to the cytoplasmic membrane through the baseplate, a paracrystalline protein structure containing BChl a and carotenoids (Car). The most important function of Car is the quenching of triplet states of BChl, which prevents the formation of singlet oxygen and thereby provides photoprotection. In our work, we studied the dynamics of the triplet states of BChl a and Car in the baseplate of Chloroflexus aurantiacus chlorosomes using picosecond differential spectroscopy. BChl a of the baseplate was excited into the Qy band at 810 nm, and the corresponding absorption changes were recorded in the range of 420-880 nm. It was found that the formation of the Car triplet state occurs in ∼1.3 ns, which is ∼3 times faster than the formation of this state in the peripheral antenna of C. aurantiacus according to literature data. The Car triplet state was recorded by the characteristic absorption band T1 → Tn at ∼550 nm. Simultaneously with the appearance of absorption T1 → Tn, there was a bleaching of the singlet absorption of Car in the region of 400-500 nm. Theoretical modeling made it possible to estimate the characteristic time of formation of the triplet state of BChl a as ∼0.5 ns. It is shown that the experimental data are well described by the sequential scheme of formation and quenching of the BChl a triplet state: BChl a* → BChl aT → CarT. Thus, carotenoids from green bacteria effectively protect the baseplate from possible damage by singlet oxygen.
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Affiliation(s)
- Andrei G Yakovlev
- Lomonosov Moscow State University, Belozersky Institute of Physico-Chemical Biology, Leninskie Gory, Moscow 119991, Russian Federation.
| | - Alexandra S Taisova
- Lomonosov Moscow State University, Belozersky Institute of Physico-Chemical Biology, Leninskie Gory, Moscow 119991, Russian Federation.
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6
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Urui T, Hayashi K, Mizuno M, Inoue K, Kandori H, Mizutani Y. Cis- Trans Reisomerization Preceding Reprotonation of the Retinal Chromophore Is Common to the Schizorhodopsin Family: A Simple and Rational Mechanism for Inward Proton Pumping. J Phys Chem B 2024; 128:744-754. [PMID: 38204413 DOI: 10.1021/acs.jpcb.3c07510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2024]
Abstract
The creation of unidirectional ion transporters across membranes represents one of the greatest challenges in chemistry. Proton-pumping rhodopsins are composed of seven transmembrane helices with a retinal chromophore bound to a lysine side chain via a Schiff base linkage and provide valuable insights for designing such transporters. What makes these transporters particularly intriguing is the discovery of both outward and inward proton-pumping rhodopsins. Surprisingly, despite sharing identical overall structures and membrane topologies, these proteins facilitate proton transport in opposite directions, implying an underlying rational mechanism that can transport protons in different directions within similar protein structures. In this study, we unraveled this mechanism by examining the chromophore structures of deprotonated intermediates in schizorhodopsins, a recently discovered subfamily of inward proton-pumping rhodopsins, using time-resolved resonance Raman spectroscopy. The photocycle of schizorhodopsins revealed the cis-trans thermal isomerization that precedes reprotonation at the Schiff base of the retinal chromophore. Notably, this order has not been observed in other proton-pumping rhodopsins, but here, it was observed in all seven schizorhodopsins studied across the archaeal domain, strongly suggesting that cis-trans thermal isomerization preceding reprotonation is a universal feature of the schizorhodopsin family. Based on these findings, we propose a structural basis for the remarkable order of events crucial for facilitating inward proton transport. The mechanism underlying inward proton transport by schizorhodopsins is straightforward and rational. The insights obtained from this study hold great promise for the design of transmembrane unidirectional ion transporters.
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Affiliation(s)
- Taito Urui
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Kouhei Hayashi
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Misao Mizuno
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Keiichi Inoue
- The Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
| | - Hideki Kandori
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya, Aichi 466-8555, Japan
| | - Yasuhisa Mizutani
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
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7
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Thwaites O, Christianson BM, Cowan AJ, Jäckel F, Liu LN, Gardner AM. Unravelling the Roles of Integral Polypeptides in Excitation Energy Transfer of Photosynthetic RC-LH1 Supercomplexes. J Phys Chem B 2023; 127:7283-7290. [PMID: 37556839 PMCID: PMC10461223 DOI: 10.1021/acs.jpcb.3c04466] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 07/24/2023] [Indexed: 08/11/2023]
Abstract
Elucidating the photosynthetic processes that occur within the reaction center-light-harvesting 1 (RC-LH1) supercomplexes from purple bacteria is crucial for uncovering the assembly and functional mechanisms of natural photosynthetic systems and underpinning the development of artificial photosynthesis. Here, we examined excitation energy transfer of various RC-LH1 supercomplexes of Rhodobacter sphaeroides using transient absorption spectroscopy, coupled with lifetime density analysis, and studied the roles of the integral transmembrane polypeptides, PufX and PufY, in energy transfer within the RC-LH1 core complex. Our results show that the absence of PufX increases both the LH1 → RC excitation energy transfer lifetime and distribution due to the role of PufX in defining the interaction and orientation of the RC within the LH1 ring. While the absence of PufY leads to the conformational shift of several LH1 subunits toward the RC, it does not result in a marked change in the excitation energy transfer lifetime.
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Affiliation(s)
- Owen Thwaites
- Stephenson
Institute of Renewable Energy, University
of Liverpool, Liverpool L69 7ZF, U.K.
- Department
of Physics, University of Liverpool, Liverpool L69 7ZE, U.K.
| | - Bern M. Christianson
- Institute
of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool L69 7ZB, U.K.
| | - Alexander J. Cowan
- Stephenson
Institute of Renewable Energy, University
of Liverpool, Liverpool L69 7ZF, U.K.
- Department
of Chemistry, University of Liverpool, Liverpool L69 7ZD, U.K.
| | - Frank Jäckel
- Stephenson
Institute of Renewable Energy, University
of Liverpool, Liverpool L69 7ZF, U.K.
- Department
of Physics, University of Liverpool, Liverpool L69 7ZE, U.K.
| | - Lu-Ning Liu
- Institute
of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool L69 7ZB, U.K.
- College
of Marine Life Sciences, and Frontiers Science Center for Deep Ocean
Multispheres and Earth System, Ocean University
of China, Qingdao 266003, China
| | - Adrian M. Gardner
- Stephenson
Institute of Renewable Energy, University
of Liverpool, Liverpool L69 7ZF, U.K.
- Department
of Chemistry, University of Liverpool, Liverpool L69 7ZD, U.K.
- Early Career
Laser Laboratory, University of Liverpool, Liverpool L69 3BX, U.K.
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8
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Tait CE, Krzyaniak MD, Stoll S. Computational tools for the simulation and analysis of spin-polarized EPR spectra. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2023; 349:107410. [PMID: 36870248 DOI: 10.1016/j.jmr.2023.107410] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 02/10/2023] [Accepted: 02/18/2023] [Indexed: 06/18/2023]
Abstract
The EPR spectra of paramagnetic species induced by photoexcitation typically exhibit enhanced absorptive and emissive features resulting from sublevel populations that differ from thermal equilibrium. The populations and the resulting spin polarization of the spectra are dictated by the selectivity of the photophysical process generating the observed state. Simulation of the spin-polarized EPR spectra is crucial in the characterization of both the dynamics of formation of the photoexcited state as well as its electronic and structural properties. EasySpin, the simulation toolbox for EPR spectroscopy, now includes extended support for the simulation of the EPR spectra of spin-polarized states of arbitrary spin multiplicity and formed by a variety of different mechanisms, including photoexcited triplet states populated by intersystem crossing, charge recombination or spin polarization transfer, spin-correlated radical pairs created by photoinduced electron transfer, triplet pairs formed by singlet fission and multiplet states arising from photoexcitation in systems containing chromophores and stable radicals. In this paper, we highlight EasySpin's capabilities for the simulation of spin-polarized EPR spectra on the basis of illustrative examples from the literature in a variety of fields ranging across chemistry, biology, material science and quantum information science.
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Affiliation(s)
- Claudia E Tait
- Department of Chemistry, University of Oxford, Oxford OX1 3QZ, United Kingdom.
| | - Matthew D Krzyaniak
- Department of Chemistry, Center for Molecular Quantum Transduction and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston 60208, IL, United States
| | - Stefan Stoll
- Department of Chemistry, University of Washington, Seattle, 98195, WA, United States
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9
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Kim J, Kim C, Kim S, Ihee H, Shin W, Kim EJ, Lee JK. The Photoactive Photosynthetic Reaction Center of a Rhodobacter sphaeroides Mutant Lacking 3-Vinyl (Bacterio)Chlorophyllide a Hydratase Contains 3-Vinyl Bacteriochlorophyll a. Microbiol Spectr 2023; 11:e0387822. [PMID: 36971575 PMCID: PMC10101016 DOI: 10.1128/spectrum.03878-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 02/20/2023] [Indexed: 03/29/2023] Open
Abstract
Rhodobacter sphaeroides mutant BF-lacking 3-vinyl (bacterio)chlorophyllide a hydratase (BchF)-accumulates chlorophyllide a (Chlide a) and 3-vinyl bacteriochlorophyllide a (3V-Bchlide a). BF synthesizes 3-vinyl bacteriochlorophyll a (3V-Bchl a) through prenylation of 3V-Bchlide a and assembles a novel reaction center (V-RC) using 3V-Bchl a and Mg-free 3-vinyl bacteriopheophytin a (3V-Bpheo a) at a molar ratio of 2:1. We aimed to verify whether a bchF-deleted R. sphaeroides mutant produces a photochemically active RC that facilitates photoheterotrophic growth. The mutant grew photoheterotrophically-implying a functional V-RC-as confirmed by the emergence of growth-competent suppressors of bchC-deleted mutant (BC) under irradiation. Suppressor mutations in BC were localized to bchF, which diminished BchF activity and caused 3V-Bchlide a accumulation. bchF expression carrying the suppressor mutations in trans resulted in the coproduction of V-RC and wild-type RC (WT-RC) in BF. The V-RC had a time constant (τ) for electron transfer from the primary electron donor P (a dimer of 3V-Bchl a) to the A-side containing 3V-Bpheo a (HA) similar to that of the WT-RC and a 60% higher τ for electron transfer from HA to quinone A (QA). Thus, the electron transfer from HA to QA in the V-RC should be slower than that in the WT-RC. Furthermore, the midpoint redox potential of P/P+ of the V-RC was 33 mV more positive than that of the WT-RC. R. sphaeroides, thus, synthesizes the V-RC when 3V-Bchlide a accumulates. The V-RC can support photoheterotrophic growth; however, its photochemical activity is inferior to that of the WT-RC. IMPORTANCE 3V-Bchlide a is an intermediate in the bacteriochlorophyll a (Bchl a)-specific biosynthetic branch and prenylated by bacteriochlorophyll synthase. R. sphaeroides synthesizes V-RC that absorbs light at short wavelengths. The V-RC was not previously discovered because 3V-Bchlide a does not accumulate during the growth of WT cells synthesizing Bchl a. The levels of reactive oxygen species increased with the onset of photoheterotrophic growth in BF, resulting in a long lag period. Although the inhibitor of BchF is unknown, the V-RC may act as a substitute for the WT-RC when BchF is completely inhibited. Alternatively, it may act synergistically with WT-RC at low levels of BchF activity. The V-RC may broaden the absorption spectra of R. sphaeroides and supplement its photosynthetic ability at various wavelengths of visible light to a greater extent than that by the WT-RC alone.
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Affiliation(s)
- June Kim
- Department of Life Science, Sogang University, Seoul, Republic of Korea
| | - Changwon Kim
- Department of Chemistry and KI for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
- Center for Advanced Reaction Dynamics, Institute for Basic Science, Daejeon, Republic of Korea
| | - Siin Kim
- Department of Chemistry and KI for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
- Center for Advanced Reaction Dynamics, Institute for Basic Science, Daejeon, Republic of Korea
| | - Hyotcherl Ihee
- Department of Chemistry and KI for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
- Center for Advanced Reaction Dynamics, Institute for Basic Science, Daejeon, Republic of Korea
| | - Woonsup Shin
- Department of Chemistry, Sogang University, Seoul, Republic of Korea
| | - Eui-Jin Kim
- Microbial Research Department, Nakdonggang National Institute of Biological Resources, Gyeongsangbuk-do, Republic of Korea
| | - Jeong K. Lee
- Department of Life Science, Sogang University, Seoul, Republic of Korea
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10
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Elbahnasawy MA, Nasr ML. DNA-nanostructure-templated assembly of planar and curved lipid-bilayer membranes. Front Chem 2023; 10:1047874. [PMID: 36844038 PMCID: PMC9944057 DOI: 10.3389/fchem.2022.1047874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 11/21/2022] [Indexed: 02/10/2023] Open
Abstract
Lipid-bilayer nanodiscs and liposomes have been developed to stabilize membrane proteins in order to study their structures and functions. Nanodiscs are detergent-free, water-soluble, and size-controlled planar phospholipid-bilayer platforms. On the other hand, liposomes are curved phospholipid-bilayer spheres with an aqueous core used as drug delivery systems and model membrane platforms for studying cellular activities. A long-standing challenge is the generation of a homogenous and monodispersed lipid-bilayer system with a very wide range of dimensions and curvatures (elongation, bending, and twisting). A DNA-origami template provides a way to control the shapes, sizes, and arrangements of lipid bilayers via enforcing the assembly of lipid bilayers within the cavities created by DNA nanostructures. Here, we provide a concise overview and discuss how to design planar and curved lipid-bilayer membranes by using DNA-origami nanostructures as templates. Finally, we will discuss the potential applications of DNA-origami nanostructures in the structural and functional studies of large membrane proteins and their complexes.
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Affiliation(s)
- Mostafa A. Elbahnasawy
- Immunology Laboratory, Botany and Microbiology Department, Faculty of Science, Al-Azhar University, Cairo, Egypt
| | - Mahmoud L. Nasr
- Renal Division and Engineering in Medicine Division, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, United States
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11
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Magdaong NCM, Faries KM, Buhrmaster JC, Tira GA, Wyllie RM, Kohout CE, Hanson DK, Laible PD, Holten D, Kirmaier C. High Yield of B-Side Electron Transfer at 77 K in the Photosynthetic Reaction Center Protein from Rhodobacter sphaeroides. J Phys Chem B 2022; 126:8940-8956. [PMID: 36315401 DOI: 10.1021/acs.jpcb.2c05905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The primary electron transfer (ET) processes at 295 and 77 K are compared for the Rhodobacter sphaeroides reaction center (RC) pigment-protein complex from 13 mutants including a wild-type control. The engineered RCs bear mutations in the L and M polypeptides that largely inhibit ET from the excited state P* of the primary electron donor (P, a bacteriochlorophyll dimer) to the normally photoactive A-side cofactors and enhance ET to the C2-symmetry related, and normally photoinactive, B-side cofactors. P* decay is multiexponential at both temperatures and modeled as arising from subpopulations that differ in contributions of two-step ET (e.g., P* → P+BB- → P+HB-), one-step superexchange ET (e.g., P* → P+HB-), and P* → ground state. [HB and BB are monomeric bacteriopheophytin and bacteriochlorophyll, respectively.] The relative abundances of the subpopulations and the inherent rate constants of the P* decay routes vary with temperature. Regardless, ET to produce P+HB- is generally faster at 77 K than at 295 K by about a factor of 2. A key finding is that the yield of P+HB-, which ranges from ∼5% to ∼90% among the mutant RCs, is essentially the same at 77 K as at 295 K in each case. Overall, the results show that ET from P* to the B-side cofactors in these mutants does not require thermal activation and involves combinations of ET mechanisms analogous to those operative on the A side in the native RC.
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Affiliation(s)
- Nikki Cecil M Magdaong
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, United States
| | - Kaitlyn M Faries
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, United States
| | - James C Buhrmaster
- Biosciences Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Gregory A Tira
- Biosciences Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Ryan M Wyllie
- Biosciences Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Claire E Kohout
- Biosciences Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Deborah K Hanson
- Biosciences Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Philip D Laible
- Biosciences Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Dewey Holten
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, United States
| | - Christine Kirmaier
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, United States
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12
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Grassino M, Batstone DJ, Yong KW, Capson-Tojo G, Hülsen T. Method development for PPB culture screening, pigment analysis with UPLC-UV-HRMS vs. spectrophotometric methods, and spectral decomposition-based analysis. Talanta 2022; 246:123490. [DOI: 10.1016/j.talanta.2022.123490] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 04/12/2022] [Accepted: 04/15/2022] [Indexed: 11/30/2022]
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13
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Sutherland GA, Qian P, Hunter CN, Swainsbury DJ, Hitchcock A. Engineering purple bacterial carotenoid biosynthesis to study the roles of carotenoids in light-harvesting complexes. Methods Enzymol 2022; 674:137-184. [DOI: 10.1016/bs.mie.2022.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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14
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Gorka M, Baldansuren A, Malnati A, Gruszecki E, Golbeck JH, Lakshmi KV. Shedding Light on Primary Donors in Photosynthetic Reaction Centers. Front Microbiol 2021; 12:735666. [PMID: 34659164 PMCID: PMC8517396 DOI: 10.3389/fmicb.2021.735666] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Accepted: 08/30/2021] [Indexed: 11/17/2022] Open
Abstract
Chlorophylls (Chl)s exist in a variety of flavors and are ubiquitous in both the energy and electron transfer processes of photosynthesis. The functions they perform often occur on the ultrafast (fs-ns) time scale and until recently, these have been difficult to measure in real time. Further, the complexity of the binding pockets and the resulting protein-matrix effects that alter the respective electronic properties have rendered theoretical modeling of these states difficult. Recent advances in experimental methodology, computational modeling, and emergence of new reaction center (RC) structures have renewed interest in these processes and allowed researchers to elucidate previously ambiguous functions of Chls and related pheophytins. This is complemented by a wealth of experimental data obtained from decades of prior research. Studying the electronic properties of Chl molecules has advanced our understanding of both the nature of the primary charge separation and subsequent electron transfer processes of RCs. In this review, we examine the structures of primary electron donors in Type I and Type II RCs in relation to the vast body of spectroscopic research that has been performed on them to date. Further, we present density functional theory calculations on each oxidized primary donor to study both their electronic properties and our ability to model experimental spectroscopic data. This allows us to directly compare the electronic properties of hetero- and homodimeric RCs.
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Affiliation(s)
- Michael Gorka
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States
| | - Amgalanbaatar Baldansuren
- Department of Chemistry and Chemical Biology and The Baruch ’60 Center for Biochemical Solar Energy Research, Rensselaer Polytechnic Institute, Troy, NY, United States
| | - Amanda Malnati
- Department of Chemistry and Chemical Biology and The Baruch ’60 Center for Biochemical Solar Energy Research, Rensselaer Polytechnic Institute, Troy, NY, United States
| | - Elijah Gruszecki
- Department of Chemistry and Chemical Biology and The Baruch ’60 Center for Biochemical Solar Energy Research, Rensselaer Polytechnic Institute, Troy, NY, United States
| | - John H. Golbeck
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States
- Department of Chemistry, The Pennsylvania State University, University Park, PA, United States
| | - K. V. Lakshmi
- Department of Chemistry and Chemical Biology and The Baruch ’60 Center for Biochemical Solar Energy Research, Rensselaer Polytechnic Institute, Troy, NY, United States
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15
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Zabelin AA, Shkuropatov AY. Pigment-modified reaction centers of Chloroflexus aurantiacus: chemical exchange of bacteriopheophytins with plant-type pheophytins. PHOTOSYNTHESIS RESEARCH 2021; 149:313-328. [PMID: 34138452 DOI: 10.1007/s11120-021-00855-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 06/06/2021] [Indexed: 06/12/2023]
Abstract
The pigment composition of isolated reaction centers (RCs) of the green filamentous bacterium Chloroflexus (Cfl.) aurantiacus was changed by chemical exchange of native bacteriopheophytin a (BPheo) molecules with externally added pheophytin a (Pheo) or [3-acetyl]-Pheo upon incubation of RC/pheophytin mixtures at room temperature and 45 °C. The modified RCs were characterized by Vis/NIR absorption spectroscopy, and the effect of pigment exchange on RC photochemical activity was assessed by measuring the photoaccumulation of the reduced pigment at the binding site HA. It is shown that both pheophytins can be exchanged into the HA site instead of BPheo by incubation at room temperature. While the newly introduced Pheo molecule is not active in electron transfer, the [3-acetyl]-Pheo molecule is able to replace functionally the photoreducible HA BPheo molecule with the formation of the [3-acetyl]-Pheo- radical anion instead of the BPheo-. After incubation at 45 °C, the majority (~ 90%) of HA BPheo molecules is replaced by both Pheo and [3-acetyl]-Pheo. Only a partial replacement of inactive BPheo molecules with pheophytins is observed even when the incubation temperature is raised to 50 °C. The results are discussed in terms of (i) differences in the accessibility of BPheo binding sites for extraneous pigments depending on structural constraints and incubation temperature and (ii) the effect of the reduction potential of pigments introduced into the HA site on the energetics of the charge separation process. The possible implication of Pheo-exchanged preparations for studying early electron-transfer events in Cfl. aurantiacus RCs is considered.
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Affiliation(s)
- Alexey A Zabelin
- Federal Research Center "Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences", Institute of Basic Biological Problems of the Russian Academy of Sciences, 142290, Pushchino, Moscow Region, Russian Federation
| | - Anatoly Ya Shkuropatov
- Federal Research Center "Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences", Institute of Basic Biological Problems of the Russian Academy of Sciences, 142290, Pushchino, Moscow Region, Russian Federation.
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16
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Bukartė E, Paleček D, Edlund P, Westenhoff S, Zigmantas D. Dynamic band-shift signal in two-dimensional electronic spectroscopy: A case of bacterial reaction center. J Chem Phys 2021; 154:115102. [PMID: 33752351 DOI: 10.1063/5.0033805] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Optical nonlinear spectroscopies carry a high amount of information about the systems under investigation; however, as they report polarization signals, the resulting spectra are often congested and difficult to interpret. To recover the landscape of energy states and physical processes such as energy and electron transfer, a clear interpretation of the nonlinear signals is prerequisite. Here, we focus on the interpretation of the electrochromic band-shift signal, which is generated when an internal electric field is established in the system following optical excitation. Whereas the derivative shape of the band-shift signal is well understood in transient absorption spectroscopy, its emergence in two-dimensional electronic spectroscopy (2DES) has not been discussed. In this work, we employed 2DES to follow the dynamic band-shift signal in reaction centers of purple bacteria Rhodobacter sphaeroides at 77 K. The prominent two-dimensional derivative-shape signal appears with the characteristic formation time of the charge separated state. To explain and characterize the band-shift signal, we use expanded double-sided Feynman diagram formalism. We propose to distinguish two types of Feynman diagrams that lead to signals with negative amplitude: excited state absorption and re-excitation. The presented signal decomposition and modeling analysis allows us to recover precise electrochromic shifts of accessory bacteriochlorophylls, identify additional signals in the B band range, and gain a further insight into the electron transfer mechanism. In a broader perspective, expanded Feynman diagram formalism will allow for interpretation of all 2D signals in a clearer and more intuitive way and therefore facilitate studying the underlying photophysics.
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Affiliation(s)
- Eglė Bukartė
- Chemical Physics, Lund University, P.O. Box 124, SE-22100 Lund, Sweden
| | - David Paleček
- Chemical Physics, Lund University, P.O. Box 124, SE-22100 Lund, Sweden
| | - Petra Edlund
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, SE-40530 Gothenburg, Sweden
| | - Sebastian Westenhoff
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, SE-40530 Gothenburg, Sweden
| | - Donatas Zigmantas
- Chemical Physics, Lund University, P.O. Box 124, SE-22100 Lund, Sweden
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17
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Ma F, Romero E, Jones MR, Novoderezhkin VI, Yu LJ, van Grondelle R. Dynamic Stark Effect in Two-Dimensional Spectroscopy Revealing Modulation of Ultrafast Charge Separation in Bacterial Reaction Centers by an Inherent Electric Field. J Phys Chem Lett 2021; 12:5526-5533. [PMID: 34096727 DOI: 10.1021/acs.jpclett.1c01059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Despite extensive study, mysteries remain regarding the highly efficient ultrafast charge separation processes in photosynthetic reaction centers (RCs). In this work, transient Stark signals were found to be present in ultrafast two-dimensional electronic spectra recorded for purple bacterial RCs at 77 K. These arose from the electric field that is inherent to the intradimer charge-transfer intermediate of the bacteriochlorophyll pair (P), PA+PB-. By comparing three mutated RCs, a correlation was found between the efficient formation of PA+PB- and a fast charge separation rate. Importantly, the energy level of P* was changed due to the Stark shift, influencing the driving force for P* → P+BA- electron transfer and hence its rate. Furthermore, the orientation and amplitude of the inherent electric field varied in different ways upon different mutation, leading to contrasting changes in the rates. This mechanism of modulation provides a solution to a long-lasting inconsistency between experimental observations and activation energy theory.
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Affiliation(s)
- Fei Ma
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Nanxincun 20, Xiangshan, Beijing 100093, China
- Department of Biophysics, Faculty of Sciences, VU University Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Elisabet Romero
- Department of Biophysics, Faculty of Sciences, VU University Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Michael R Jones
- School of Biochemistry, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, U.K
| | - Vladimir I Novoderezhkin
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Leninskie Gory, 119992 Moscow, Russia
| | - Long-Jiang Yu
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Nanxincun 20, Xiangshan, Beijing 100093, China
| | - Rienk van Grondelle
- Department of Biophysics, Faculty of Sciences, VU University Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
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18
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Poluektov OG, Utschig LM. Quantum Sensing of Electron Transfer Pathways in Natural Photosynthesis Using Time-Resolved High-Field Electron Paramagnetic Resonance/Electron-Nuclear Double Resonance Spectroscopy. J Phys Chem B 2021; 125:4025-4030. [PMID: 33877826 DOI: 10.1021/acs.jpcb.1c00946] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Photosynthetic integral membrane reaction center (RC) proteins capture and convert sunlight into chemical energy via efficient charge separation achieved through a series of rapid, photoinitiated electron transfer steps. These fast electron transfers create an entangled spin qubit (radical) pair that contains detailed information about the weak magnetic interactions, structure, and dynamics of localized protein environments involved in charge separation events. Herein, we investigate how these entangled electron spin qubits interact with nuclear spins of the protein environment using the high spectral resolution of 130 GHz electron paramagnetic resonance (EPR) and electron-nuclear double resonance (ENDOR). Spectroscopic interrogation enabled the observation and probing of protons located in the electron transfer pathway between the membrane-spanning electron pair P+QA- (where P+ is the primary donor, a special pair of bacteriochlorophylls, and QA is the primary quinone acceptor) in the bacterial RC. Spectroscopic analysis reveals hydrogen-bonding interactions involved in regulating the route that light-induced electrons travel through the RC protein during charge separation.
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Affiliation(s)
- Oleg G Poluektov
- Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Lemont, Illinois 60439, United States
| | - Lisa M Utschig
- Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Lemont, Illinois 60439, United States
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19
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Białek R, Thakur K, Ruff A, Jones MR, Schuhmann W, Ramanan C, Gibasiewicz K. Insight into Electron Transfer from a Redox Polymer to a Photoactive Protein. J Phys Chem B 2020; 124:11123-11132. [PMID: 33236901 PMCID: PMC7735723 DOI: 10.1021/acs.jpcb.0c08714] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 11/10/2020] [Indexed: 11/29/2022]
Abstract
Biohybrid photoelectrochemical systems in photovoltaic or biosensor applications have gained considerable attention in recent years. While the photoactive proteins engaged in such systems usually maintain an internal charge separation quantum yield of nearly 100%, the subsequent steps of electron and hole transfer beyond the protein often limit the overall system efficiency and their kinetics remain largely uncharacterized. To reveal the dynamics of one of such charge-transfer reactions, we report on the reduction of Rhodobacter sphaeroides reaction centers (RCs) by Os-complex-modified redox polymers (P-Os) characterized using transient absorption spectroscopy. RCs and P-Os were mixed in buffered solution in different molar ratios in the presence of a water-soluble quinone as an electron acceptor. Electron transfer from P-Os to the photoexcited RCs could be described by a three-exponential function, the fastest lifetime of which was on the order of a few microseconds, which is a few orders of magnitude faster than the internal charge recombination of RCs with fully separated charge. This was similar to the lifetime for the reduction of RCs by their natural electron donor, cytochrome c2. The rate of electron donation increased with increasing ratio of polymer to protein concentrations. It is proposed that P-Os and RCs engage in electrostatic interactions to form complexes, the sizes of which depend on the polymer-to-protein ratio. Our findings throw light on the processes within hydrogel-based biophotovoltaic devices and will inform the future design of materials optimally suited for this application.
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Affiliation(s)
- Rafał Białek
- Faculty
of Physics, Adam Mickiewicz University, Poznań, ul. Uniwersytetu
Poznańskiego 2, 61-614 Poznań, Poland
| | - Kalyani Thakur
- Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Adrian Ruff
- Analytical
Chemistry—Center for Electrochemical Sciences, Faculty of Biochemistry
and Chemistry, Faculty of Biochemistry and Chemistry, Ruhr-University Bochum, Universitätsstrasse 150, D-44780 Bochum, Germany
| | - Michael R. Jones
- School
of Biochemistry, Biomedical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, U.K.
| | - Wolfgang Schuhmann
- Analytical
Chemistry—Center for Electrochemical Sciences, Faculty of Biochemistry
and Chemistry, Faculty of Biochemistry and Chemistry, Ruhr-University Bochum, Universitätsstrasse 150, D-44780 Bochum, Germany
| | - Charusheela Ramanan
- Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Krzysztof Gibasiewicz
- Faculty
of Physics, Adam Mickiewicz University, Poznań, ul. Uniwersytetu
Poznańskiego 2, 61-614 Poznań, Poland
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20
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Khristin AM, Zabelin AA, Fufina TY, Khatypov RA, Proskuryakov II, Shuvalov VA, Shkuropatov AY, Vasilieva LG. Mutation H(M202)L does not lead to the formation of a heterodimer of the primary electron donor in reaction centers of Rhodobacter sphaeroides when combined with mutation I(M206)H. PHOTOSYNTHESIS RESEARCH 2020; 146:109-121. [PMID: 32125564 DOI: 10.1007/s11120-020-00728-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 02/17/2020] [Indexed: 06/10/2023]
Abstract
In photosynthetic reaction centers (RCs) of purple bacteria, conserved histidine residues [His L173 and His M202 in Rhodobacter (Rba.) sphaeroides] are known to serve as fifth axial ligands to the central Mg atom of the bacteriochlorophyll (BChl) molecules (PA and PB, respectively) that constitute the homodimer (BChl/BChl) primary electron donor P. In a number of previous studies, it has been found that replacing these residues with leucine, which cannot serve as a ligand to the Mg ion of BChl, leads to the assembly of heterodimer RCs with P represented by the BChl/BPheo pair. Here, we show that a homodimer P is assembled in Rba. sphaeroides RCs if the mutation H(M202)L is combined with the mutation of isoleucine to histidine at position M206 located in the immediate vicinity of PB. The resulting mutant H(M202)L/I(M206)H RCs are characterized using pigment analysis, redox titration, and a number of spectroscopic methods. It is shown that, compared to wild-type RCs, the double mutation causes significant changes in the absorption spectrum of the P homodimer and the electronic structure of the radical cation P+, but has only minor effect on the pigment composition, the P/P+ midpoint potential, and the initial electron-transfer reaction. The results are discussed in terms of the nature of the axial ligand to the Mg of PB in mutant H(M202)L/I(M206)H RCs and the possibility of His M202 participation in the previously proposed through-bond route for electron transfer from the excited state P* to the monomeric BChl BA in wild-type RCs.
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Affiliation(s)
- Anton M Khristin
- Institute of Basic Biological Problems of the Russian Academy of Sciences, Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences, Pushchino, 142290, Moscow, Russian Federation
| | - Alexey A Zabelin
- Institute of Basic Biological Problems of the Russian Academy of Sciences, Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences, Pushchino, 142290, Moscow, Russian Federation
| | - Tatiana Yu Fufina
- Institute of Basic Biological Problems of the Russian Academy of Sciences, Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences, Pushchino, 142290, Moscow, Russian Federation
| | - Ravil A Khatypov
- Institute of Basic Biological Problems of the Russian Academy of Sciences, Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences, Pushchino, 142290, Moscow, Russian Federation
| | - Ivan I Proskuryakov
- Institute of Basic Biological Problems of the Russian Academy of Sciences, Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences, Pushchino, 142290, Moscow, Russian Federation
| | - Vladimir A Shuvalov
- Institute of Basic Biological Problems of the Russian Academy of Sciences, Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences, Pushchino, 142290, Moscow, Russian Federation
| | - Anatoly Ya Shkuropatov
- Institute of Basic Biological Problems of the Russian Academy of Sciences, Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences, Pushchino, 142290, Moscow, Russian Federation
| | - Lyudmila G Vasilieva
- Institute of Basic Biological Problems of the Russian Academy of Sciences, Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences, Pushchino, 142290, Moscow, Russian Federation.
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21
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Zabelin AA, Khristin AM, Shkuropatova VA, Khatypov RA, Shkuropatov AY. Primary electron transfer in Rhodobacter sphaeroides R-26 reaction centers under dehydration conditions. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1861:148238. [PMID: 32533935 DOI: 10.1016/j.bbabio.2020.148238] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 05/28/2020] [Accepted: 06/03/2020] [Indexed: 11/26/2022]
Abstract
The photoinduced charge separation in QB-depleted reaction centers (RCs) from Rhodobacter sphaeroides R-26 in solid air-dried and vacuum-dried (~10-2 Torr) films, obtained in the presence of detergent n-dodecyl-β-D-maltoside (DM), is characterized using ultrafast transient absorption spectroscopy. It is shown that drying of RC-DM complexes is accompanied by reversible blue shifts of the ground-state absorption bands of the pigment ensemble, which suggest that no dehydration-induced structural destruction of RCs occurs in both types of films. In air-dried films, electron transfer from the excited primary electron donor P⁎ to the photoactive bacteriopheophytin HA proceeds in 4.7 ps to form the P+HA- state with essentially 100% yield. P+HA- decays in 260 ps both by electron transfer to the primary quinone QA to give the state P+QA- (87% yield) and by charge recombination to the ground state (13% yield). In vacuum-dried films, P⁎ decay is characterized by two kinetic components with time constants of 4.1 and 46 ps in a proportion of ~55%/45%, and P+HA- decays about 2-fold slower (462 ps) than in air-dried films. Deactivation of both P⁎ and P+HA- to the ground state effectively competes with the corresponding forward electron-transfer reactions in vacuum-dried RCs, reducing the yield of P+QA- to 68%. The results are compared with the data obtained for fully hydrated RCs in solution and are discussed in terms of the presence in the RC complexes of different water molecules, the removal/displacement of which affects spectral properties of pigment cofactors and rates and yields of the electron-transfer reactions.
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Affiliation(s)
- Alexey A Zabelin
- Institute of Basic Biological Problems of the Russian Academy of Sciences, Federal Research Center "Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences", 142290 Pushchino, Moscow Region, Russian Federation
| | - Anton M Khristin
- Institute of Basic Biological Problems of the Russian Academy of Sciences, Federal Research Center "Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences", 142290 Pushchino, Moscow Region, Russian Federation
| | - Valentina A Shkuropatova
- Institute of Basic Biological Problems of the Russian Academy of Sciences, Federal Research Center "Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences", 142290 Pushchino, Moscow Region, Russian Federation
| | - Ravil A Khatypov
- Institute of Basic Biological Problems of the Russian Academy of Sciences, Federal Research Center "Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences", 142290 Pushchino, Moscow Region, Russian Federation
| | - Anatoly Ya Shkuropatov
- Institute of Basic Biological Problems of the Russian Academy of Sciences, Federal Research Center "Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences", 142290 Pushchino, Moscow Region, Russian Federation.
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22
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Gorka M, Cherepanov DA, Semenov AY, Golbeck JH. Control of electron transfer by protein dynamics in photosynthetic reaction centers. Crit Rev Biochem Mol Biol 2020; 55:425-468. [PMID: 32883115 DOI: 10.1080/10409238.2020.1810623] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Trehalose and glycerol are low molecular mass sugars/polyols that have found widespread use in the protection of native protein states, in both short- and long-term storage of biological materials, and as a means of understanding protein dynamics. These myriad uses are often attributed to their ability to form an amorphous glassy matrix. In glycerol, the glass is formed only at cryogenic temperatures, while in trehalose, the glass is formed at room temperature, but only upon dehydration of the sample. While much work has been carried out to elucidate a mechanistic view of how each of these matrices interact with proteins to provide stability, rarely have the effects of these two independent systems been directly compared to each other. This review aims to compile decades of research on how different glassy matrices affect two types of photosynthetic proteins: (i) the Type II bacterial reaction center from Rhodobacter sphaeroides and (ii) the Type I Photosystem I reaction center from cyanobacteria. By comparing aggregate data on electron transfer, protein structure, and protein dynamics, it appears that the effects of these two distinct matrices are remarkably similar. Both seem to cause a "tightening" of the solvation shell when in a glassy state, resulting in severely restricted conformational mobility of the protein and associated water molecules. Thus, trehalose appears to be able to mimic, at room temperature, nearly all of the effects on protein dynamics observed in low temperature glycerol glasses.
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Affiliation(s)
- Michael Gorka
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
| | - Dmitry A Cherepanov
- N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, Moscow, Russia.,A.N. Belozersky Institute of Physical-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Alexey Yu Semenov
- N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, Moscow, Russia.,A.N. Belozersky Institute of Physical-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - John H Golbeck
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA.,Department of Chemistry, The Pennsylvania State University, University Park, PA, USA
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23
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Oja V, Laisk A. Time- and reduction-dependent rise of photosystem II fluorescence during microseconds-long inductions in leaves. PHOTOSYNTHESIS RESEARCH 2020; 145:209-225. [PMID: 32918663 DOI: 10.1007/s11120-020-00783-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 09/02/2020] [Indexed: 05/16/2023]
Abstract
Lettuce (Lactuca sativa) and benth (Nicotiana benthamiana) leaves were illuminated with 720 nm background light to mix S-states and oxidize electron carriers. Green-filtered xenon flashes of different photon dose were applied and O2 evolution induced by a flash was measured. After light intensity gradient across the leaf was mathematically considered, the flash-induced PSII electron transport (= 4·O2 evolution) exponentially increased with the flash photon dose in any differential layer of the leaf optical density. This proved the absence of excitonic connectivity between PSII units. Time courses of flash light intensity and 680 nm chlorophyll fluorescence emission were recorded. While with connected PSII the sigmoidal fluorescence rise has been explained by quenching of excitation in closed PSII by its open neighbors, in the absence of connectivity the sigmoidicity indicates gradual rise of the fluorescence yield of an individual closed PSII during the induction. Two phases were discerned: the specific fluorescence yield immediately increased from Fo to 1.8Fo in a PSII, whose reaction center became closed; fluorescence yield of the closed PSII was keeping time-dependent rise from 1.8Fo to about 3Fo, approaching the flash fluorescence yield Ff = 0.6Fm during 40 μs. The time-dependent fluorescence rise was resolved from the quenching by 3Car triplets and related to protein conformational change. We suggest that QA reduction induces a conformational change, which by energetic or structural means closes the gate for excitation entrance into the central radical pair trap-efficiently when QB cannot accept the electron, but less efficiently when it can.
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Affiliation(s)
- Vello Oja
- Institute of Technology, University of Tartu, Nooruse st. 1, 50411, Tartu, Estonia
| | - Agu Laisk
- Institute of Technology, University of Tartu, Nooruse st. 1, 50411, Tartu, Estonia.
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24
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Modafferi D, Zazubovich V, Kálmán L. Bound detergent molecules in bacterial reaction centers facilitate detection of tetryl explosive. PHOTOSYNTHESIS RESEARCH 2020; 145:145-157. [PMID: 32632533 DOI: 10.1007/s11120-020-00770-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 06/24/2020] [Indexed: 06/11/2023]
Abstract
Bacterial reaction centers (BRC) from Rhodobacter sphaeroides were found to accelerate, about 100-fold, the reaction between tetryl (2,4,6-trinitrophenylmethylnitramine) explosive and n-lauryl-N-N-dimethylamine-N-oxide (LDAO) that results in the formation of picric acid-like product with characteristic UV-VIS absorption spectrum with peaks at 345 and 415 nm. Moreover, this product also affects the spectra of BRC cofactors in the NIR spectral region and stabilizes the conformational changes associated with slow charge recombination. The evolution of the NIR absorption changes correlated with the kinetics of the product formation. Comparison between the wild-type and the R26 carotenoid-less strain indicates that tetryl-LDAO reaction is roughly five times faster for R26, which allows for identifying the carotenoid binding site as the optimal reaction site. Another, less-defined reaction site is located in the BRC's hydrophobic cavity. These effects are highly selective for tetryl and not observed for several other widespread nitric explosives; slowed-down charge recombination allows for distinguishing between tetryl and QB-site herbicides. The current limit of detection is in the ppb range or ~ 100 nM. Details of the molecular mechanisms of the reactions and perspectives of using these effects in bioassays or biosensors for explosives detection are also discussed.
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Affiliation(s)
- Daniel Modafferi
- Department of Physics, Concordia University, 7141 Sherbrooke Street West, Montreal, QC, H4B 1R6, Canada
- Department of Chemical Engineering, McGill University, Montreal, QC, Canada
| | - Valter Zazubovich
- Department of Physics, Concordia University, 7141 Sherbrooke Street West, Montreal, QC, H4B 1R6, Canada.
| | - László Kálmán
- Department of Physics, Concordia University, 7141 Sherbrooke Street West, Montreal, QC, H4B 1R6, Canada.
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25
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Aksu H, Schubert A, Bhandari S, Yamada A, Geva E, Dunietz BD. On the Role of the Special Pair in Photosystems as a Charge Transfer Rectifier. J Phys Chem B 2020; 124:1987-1994. [PMID: 32109062 DOI: 10.1021/acs.jpcb.9b11431] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The special pair, a bacteriochlorophyll a (BChl) dimer found at the core of bacterial reaction centers, is known to play a key role in the functionality of photosystems as a precursor to the photosynthesis process. In this paper, we analyze the inherent affinity of the special pair to rectify the intrapair photo-induced charge transfer (CT). In particular, we show that the molecular environment affects the nuclear geometry, resulting in symmetry breaking between the two possible intrapair CT processes. To this end, we study the relationships of the intrapair CT and the molecular geometry with respect to the effective dielectric constant provided by the molecular environment. We identify the special pair structural feature that breaks the symmetry between the two molecules, leading to CT rectification. Excited state energies, oscillator strengths, and electronic coupling values are obtained via time-dependent density functional theory, employing a recently developed framework based on a screened range-separated hybrid functional within a polarizable continuum model (SRSH-PCM). We analyze the rectification capability of the special pair by calculating the CT rates using a first-principles-based Fermi's golden rule approach.
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Affiliation(s)
- Huseyin Aksu
- Department of Chemistry and Biochemistry, Kent State University, Kent, Ohio 44242, United States
| | - Alexander Schubert
- Department of Chemistry and Biochemistry, Kent State University, Kent, Ohio 44242, United States.,Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Srijana Bhandari
- Department of Chemistry and Biochemistry, Kent State University, Kent, Ohio 44242, United States
| | - Atsushi Yamada
- Center for Computational Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577 Japan
| | - Eitan Geva
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Barry D Dunietz
- Department of Chemistry and Biochemistry, Kent State University, Kent, Ohio 44242, United States
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26
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Switching sides-Reengineered primary charge separation in the bacterial photosynthetic reaction center. Proc Natl Acad Sci U S A 2019; 117:865-871. [PMID: 31892543 DOI: 10.1073/pnas.1916119117] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We report 90% yield of electron transfer (ET) from the singlet excited state P* of the primary electron-donor P (a bacteriochlorophyll dimer) to the B-side bacteriopheophytin (HB) in the bacterial photosynthetic reaction center (RC). Starting from a platform Rhodobacter sphaeroides RC bearing several amino acid changes, an Arg in place of the native Leu at L185-positioned over one face of HB and only ∼4 Å from the 4 central nitrogens of the HB macrocycle-is the key additional mutation providing 90% yield of P+HB - This all but matches the near-unity yield of A-side P+HA - charge separation in the native RC. The 90% yield of ET to HB derives from (minimally) 3 P* populations with distinct means of P* decay. In an ∼40% population, P* decays in ∼4 ps via a 2-step process involving a short-lived P+BB - intermediate, analogous to initial charge separation on the A side of wild-type RCs. In an ∼50% population, P* → P+HB - conversion takes place in ∼20 ps by a superexchange mechanism mediated by BB An ∼10% population of P* decays in ∼150 ps largely by internal conversion. These results address the long-standing dichotomy of A- versus B-side initial charge separation in native RCs and have implications for the mechanism(s) and timescale of initial ET that are required to achieve a near-quantitative yield of unidirectional charge separation.
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27
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Aksu H, Schubert A, Geva E, Dunietz BD. Explaining Spectral Asymmetries and Excitonic Characters of the Core Pigment Pairs in the Bacterial Reaction Center Using a Screened Range-Separated Hybrid Functional. J Phys Chem B 2019; 123:8970-8975. [DOI: 10.1021/acs.jpcb.9b07646] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Huseyin Aksu
- Department of Chemistry and Biochemistry, Kent State University, Kent, Ohio 44242, United States
| | - Alexander Schubert
- Department of Chemistry and Biochemistry, Kent State University, Kent, Ohio 44242, United States
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Eitan Geva
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Barry D. Dunietz
- Department of Chemistry and Biochemistry, Kent State University, Kent, Ohio 44242, United States
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28
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Kumar A, Iyengar SS. Fragment-Based Electronic Structure for Potential Energy Surfaces Using a Superposition of Fragmentation Topologies. J Chem Theory Comput 2019; 15:5769-5786. [DOI: 10.1021/acs.jctc.9b00608] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Anup Kumar
- Department of Chemistry and Department of Physics, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana-47405, United States
| | - Srinivasan S. Iyengar
- Department of Chemistry and Department of Physics, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana-47405, United States
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29
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Faries KM, Kohout CE, Wang GX, Hanson DK, Holten D, Laible PD, Kirmaier C. Consequences of saturation mutagenesis of the protein ligand to the B-side monomeric bacteriochlorophyll in reaction centers from Rhodobacter capsulatus. PHOTOSYNTHESIS RESEARCH 2019; 141:273-290. [PMID: 30859455 DOI: 10.1007/s11120-019-00626-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Accepted: 02/07/2019] [Indexed: 06/09/2023]
Abstract
In bacterial reaction centers (RCs), photon-induced initial charge separation uses an A-side bacteriochlorophyll (BChl, BA) and bacteriopheophytin (BPh, HA), while the near-mirror image B-side BB and HB cofactors are inactive. Two new sets of Rhodobacter capsulatus RC mutants were designed, both bearing substitution of all amino acids for the native histidine M180 (M-polypeptide residue 180) ligand to the core Mg ion of BB. Residues are identified that largely result in retention of a BChl in the BB site (Asp, Ser, Pro, Gln, Asn, Gly, Cys, Lys, and Thr), ones that largely harbor the Mg-free BPh in the BB site (Leu and Ile), and ones for which isolated RCs are comprised of a substantial mixture of these two RC types (Ala, Glu, Val, Met and, in one set, Arg). No protein was isolated when M180 is Trp, Tyr, Phe, or (in one set) Arg. These findings are corroborated by ground state spectra, pigment extractions, ultrafast transient absorption studies, and the yields of B-side transmembrane charge separation. The changes in coordination chemistries did not reveal an RC with sufficiently precise poising of the redox properties of the BB-site cofactor to result in a high yield of B-side electron transfer to HB. Insights are gleaned into the amino acid properties that support BChl in the BB site and into the widely observed multi-exponential decay of the excited state of the primary electron donor. The results also have direct implications for tuning free energies of the charge-separated intermediates in RCs and mimetic systems.
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Affiliation(s)
- Kaitlyn M Faries
- Department of Chemistry, Washington University, St. Louis, MO, 63130, USA
| | - Claire E Kohout
- Biosciences Division, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Grace Xiyu Wang
- Biosciences Division, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Deborah K Hanson
- Biosciences Division, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Dewey Holten
- Department of Chemistry, Washington University, St. Louis, MO, 63130, USA
| | - Philip D Laible
- Biosciences Division, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Christine Kirmaier
- Department of Chemistry, Washington University, St. Louis, MO, 63130, USA.
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30
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Koua FHM. Structural Changes in the Acceptor Site of Photosystem II upon Ca 2+/Sr 2+ Exchange in the Mn 4CaO 5 Cluster Site and the Possible Long-Range Interactions. Biomolecules 2019; 9:E371. [PMID: 31416291 PMCID: PMC6722538 DOI: 10.3390/biom9080371] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 08/12/2019] [Indexed: 01/15/2023] Open
Abstract
The Mn4CaO5 cluster site in the oxygen-evolving complex (OEC) of photosystem II (PSII) undergoes structural perturbations, such as those induced by Ca2+/Sr2+ exchanges or Ca/Mn removal. These changes have been known to induce long-range positive shifts (between +30 and +150 mV) in the redox potential of the primary quinone electron acceptor plastoquinone A (QA), which is located 40 Å from the OEC. To further investigate these effects, we reanalyzed the crystal structure of Sr-PSII resolved at 2.1 Å and compared it with the native Ca-PSII resolved at 1.9 Å. Here, we focus on the acceptor site and report the possible long-range interactions between the donor, Mn4Ca(Sr)O5 cluster, and acceptor sites.
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Affiliation(s)
- Faisal Hammad Mekky Koua
- Center for Free Electron Laser Science, Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, 22607 Hamburg, Germany.
- National University Biomedical Research Institute, National University-Sudan, Air St. PO Box 3783, Khartoum, Sudan.
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31
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Poluektov OG, Niklas J, Utschig LM. Spin-Correlated Radical Pairs as Quantum Sensors of Bidirectional ET Mechanisms in Photosystem I. J Phys Chem B 2019; 123:7536-7544. [DOI: 10.1021/acs.jpcb.9b06636] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Oleg G. Poluektov
- Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 S. Cass Avenue, Lemont, Illinois 60439, United States
| | - Jens Niklas
- Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 S. Cass Avenue, Lemont, Illinois 60439, United States
| | - Lisa M. Utschig
- Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 S. Cass Avenue, Lemont, Illinois 60439, United States
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32
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Studying hydrogen bonding and dynamics of the acetylate groups of the Special Pair of Rhodobacter sphaeroides WT. Sci Rep 2019; 9:10528. [PMID: 31324886 PMCID: PMC6642110 DOI: 10.1038/s41598-019-46903-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 07/08/2019] [Indexed: 11/17/2022] Open
Abstract
Although the cofactors in the bacterial reaction centre of Rhodobacter sphaeroides wild type (WT) are arranged almost symmetrically in two branches, the light-induced electron transfer occurs selectively in one branch. As origin of this functional symmetry break, a hydrogen bond between the acetyl group of PL in the primary donor and His-L168 has been discussed. In this study, we investigate the existence and rigidity of this hydrogen bond with solid-state photo-CIDNP MAS NMR methods offering information on the local electronic structure due to highly sensitive and selective NMR experiments. On the time scale of the experiment, the hydrogen bond between PL and His-L168 appears to be stable and not to be affected by illumination confirming a structural asymmetry within the Special Pair.
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33
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Barabash Y, Serdenko T, Knox P, Golub A. Use of a system of differential equations to analyze the functioning of a catalytic bio macromolecule under non equilibrium conditions. Heliyon 2019; 5:e02108. [PMID: 31372558 PMCID: PMC6656994 DOI: 10.1016/j.heliyon.2019.e02108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 05/13/2019] [Accepted: 07/15/2019] [Indexed: 10/31/2022] Open
Abstract
The aim of the work is to analyze the response of a biomolecule to an external influence based on the study of its hidden states by identifying differential equations with constant coefficients. The relevance of the work lies in the fact that often the main reaction of an object to an external action can be represented as a sum of various exponential functions with a common starting point and a material balance equation. In this case, the response of an object to an external action corresponds to a system of differential equations with constant coefficients. This character of the main reaction may be due to the influence of the hidden properties of the object, which play the role of regulatory parameters. The problem is that the hidden factors and the system of differential equations are not identified. As an object, isolated reaction centers (RC) of the bacteria Rhodobacter sphaeroides, which possess the above properties, has used. Their structure is well studied. As result of studying of photo excitation processes of the reaction center has shown that electron transfer kinetics (the main reaction) can be approximated by three normalized exponential functions. Program was developed to identify for four differential equations of electron transfer and the balance equation, the behavior of hidden states of the reaction center. It was concluded that time the dependence the probability density of finding an electron in different conformational states of the reaction center characterizes the space-time changes in the structure of the reaction center.
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34
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Perets EA, Yan ECY. Chiral Water Superstructures around Antiparallel β-Sheets Observed by Chiral Vibrational Sum Frequency Generation Spectroscopy. J Phys Chem Lett 2019; 10:3395-3401. [PMID: 31070921 PMCID: PMC9059516 DOI: 10.1021/acs.jpclett.9b00878] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Hydration modulates every aspect of protein structure and function. However, studying water structures in hydration shells remains challenging mostly due to overwhelming background from bulk water. We used vibrational sum frequency generation (SFG) spectroscopy to characterize hydrated films of an antiparallel β-sheet peptide (LK7β) adsorbed on glass slides. The hydrated films give chiral SFG response from water only when the peptide self-assembles into antiparallel β-sheets. Experiments of isotopic labeling, isotopic dilution of water, and H2O-D2O exchange kinetics corroborate the assignments of the chiral SFG response to water stretching modes. Because individual water molecules are achiral, the chiral SFG response indicates formation of chiral superstructures of water around the antiparallel β-sheet, implying that a protein secondary structure can imprint its chirality onto the surrounding water. This result demonstrates chiral SFG spectroscopy as a promising tool for probing water structures in protein hydration and addressing fundamental questions of protein structure-function.
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Affiliation(s)
- Ethan A. Perets
- Department of Chemistry, Yale University, New Haven, Connecticut 06520 United States
| | - E. Chui-Ying Yan
- Department of Chemistry, Yale University, New Haven, Connecticut 06520 United States
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35
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Proton leakage across lipid bilayers: Oxygen atoms of phospholipid ester linkers align water molecules into transmembrane water wires. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1860:439-451. [PMID: 30904457 DOI: 10.1016/j.bbabio.2019.03.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 02/20/2019] [Accepted: 03/10/2019] [Indexed: 12/31/2022]
Abstract
Up to half of the cellular energy gets lost owing to membrane proton leakage. The permeability of lipid bilayers to protons is by several orders of magnitude higher than to other cations, which implies efficient proton-specific passages. The nature of these passages remains obscure. By combining experimental measurements of proton flow across phosphatidylcholine vesicles, steered molecular dynamics (MD) simulations of phosphatidylcholine bilayers and kinetic modelling, we have analyzed whether protons could pass between opposite phospholipid molecules when they sporadically converge. The MD simulations showed that each time, when the phosphorus atoms of the two phosphatidylcholine molecules got closer than 1.6 nm, the eight oxygen atoms of their ester linkages could form a transmembrane 'oxygen passage' along which several water molecules aligned into a water wire. Proton permeability along such water wires would be limited by rearrangement of oxygen atoms, which could explain the experimentally shown independence of the proton permeability of pH, H2O/D2O substitution, and membrane dipole potential. We suggest that protons can cross lipid bilayers by moving along short, self-sustaining water wires supported by oxygen atoms of lipid ester linkages.
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36
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Ma F, Romero E, Jones MR, Novoderezhkin VI, van Grondelle R. Both electronic and vibrational coherences are involved in primary electron transfer in bacterial reaction center. Nat Commun 2019; 10:933. [PMID: 30804346 PMCID: PMC6389996 DOI: 10.1038/s41467-019-08751-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 01/15/2019] [Indexed: 11/09/2022] Open
Abstract
Understanding the mechanism behind the near-unity efficiency of primary electron transfer in reaction centers is essential for designing performance-enhanced artificial solar conversion systems to fulfill mankind’s growing demands for energy. One of the most important challenges is distinguishing electronic and vibrational coherence and establishing their respective roles during charge separation. In this work we apply two-dimensional electronic spectroscopy to three structurally-modified reaction centers from the purple bacterium Rhodobacter sphaeroides with different primary electron transfer rates. By comparing dynamics and quantum beats, we reveal that an electronic coherence with dephasing lifetime of ~190 fs connects the initial excited state, P*, and the charge-transfer intermediate \documentclass[12pt]{minimal}
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\begin{document}$${\mathrm{P}}_{\mathrm{A}}^ + {\mathrm{P}}_{\mathrm{B}}^ -$$\end{document}PA+PB-; this \documentclass[12pt]{minimal}
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\begin{document}$${\mathrm{P}}^ \ast \to {\mathrm{P}}_{\mathrm{A}}^ + {\mathrm{P}}_{\mathrm{B}}^ -$$\end{document}P*→PA+PB- step is associated with a long-lived quasi-resonant vibrational coherence; and another vibrational coherence is associated with stabilizing the primary photoproduct, \documentclass[12pt]{minimal}
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\begin{document}$${\mathrm{P}}^ + {\mathrm{B}}_{\mathrm{A}}^ -$$\end{document}P+BA-. The results show that both electronic and vibrational coherences are involved in primary electron transfer process and they correlate with the super-high efficiency. Distinguishing electronic and vibrational coherences helps to clarify the near-unity efficiency of primary electron transfer in reaction centres. Here, the authors report their respective correlation with the electron transfer rate by comparing the 2D electronic spectra of three mutant reaction centres.
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Affiliation(s)
- Fei Ma
- Department of Biophysics, Faculty of Sciences, VU University Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands.
| | - Elisabet Romero
- Department of Biophysics, Faculty of Sciences, VU University Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Michael R Jones
- School of Biochemistry, University of Bristol, Biomedical Sciences Building, University Walk, Bristol, BS8 1TD, UK
| | - Vladimir I Novoderezhkin
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Leninskie Gory, Moscow, 119992, Russia
| | - Rienk van Grondelle
- Department of Biophysics, Faculty of Sciences, VU University Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
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37
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Saggu M, Fried SD, Boxer SG. Local and Global Electric Field Asymmetry in Photosynthetic Reaction Centers. J Phys Chem B 2019; 123:1527-1536. [PMID: 30668130 DOI: 10.1021/acs.jpcb.8b11458] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The origin of unidirectional electron transfer in photosynthetic reaction centers (RCs) has been widely discussed. Despite the high level of structural similarity between the two branches of pigments that participate in the initial electron transfer steps of photosynthesis, electron transfer only occurs along one branch. One possible explanation for this functional asymmetry is the differences in the electrostatic environment between the active and the inactive branches arising from the charges and dipoles of the organized protein structure. We present an analysis of electric fields in the RC of the purple bacterium Rhodobacter sphaeroides using the intrinsic carbonyl groups of the pigments as vibrational reporters whose vibrational frequency shifts can be converted into electric fields based on the vibrational Stark effect and also provide Stark effect data for plant pigments that can be used in future studies. The carbonyl stretches of the isolated pigments show pronounced Stark effects. We use these data, solvatochromism, molecular dynamics simulations, and data in the literature from IR and Raman spectra to evaluate differences in fields at symmetry-related positions, in particular at the 9-keto and 2-acetyl positions of the pigments involved in primary charge separation.
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Affiliation(s)
- Miguel Saggu
- Department of Chemistry , Stanford University , Stanford , California 94305-5080 , United States
| | - Stephen D Fried
- Department of Chemistry , Stanford University , Stanford , California 94305-5080 , United States
| | - Steven G Boxer
- Department of Chemistry , Stanford University , Stanford , California 94305-5080 , United States
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38
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Leiger K, Linnanto JM, Rätsep M, Timpmann K, Ashikhmin AA, Moskalenko AA, Fufina TY, Gabdulkhakov AG, Freiberg A. Controlling Photosynthetic Excitons by Selective Pigment Photooxidation. J Phys Chem B 2018; 123:29-38. [DOI: 10.1021/acs.jpcb.8b08083] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Kristjan Leiger
- Institute of Physics, University of Tartu, W. Ostwaldi 1, Tartu 50411, Estonia
| | - Juha Matti Linnanto
- Institute of Physics, University of Tartu, W. Ostwaldi 1, Tartu 50411, Estonia
| | - Margus Rätsep
- Institute of Physics, University of Tartu, W. Ostwaldi 1, Tartu 50411, Estonia
| | - Kõu Timpmann
- Institute of Physics, University of Tartu, W. Ostwaldi 1, Tartu 50411, Estonia
| | | | | | | | | | - Arvi Freiberg
- Institute of Physics, University of Tartu, W. Ostwaldi 1, Tartu 50411, Estonia
- Institute of Molecular and Cell Biology, University of Tartu, Riia 23, Tartu 51014, Estonia
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39
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Konar A, Sechrist R, Song Y, Policht VR, Laible PD, Bocian DF, Holten D, Kirmaier C, Ogilvie JP. Electronic Interactions in the Bacterial Reaction Center Revealed by Two-Color 2D Electronic Spectroscopy. J Phys Chem Lett 2018; 9:5219-5225. [PMID: 30136848 DOI: 10.1021/acs.jpclett.8b02394] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The bacterial reaction center (BRC) serves as an important model system for understanding the charge separation processes in photosynthesis. Knowledge of the electronic structure of the BRC is critical for understanding its charge separation mechanism. While it is well-accepted that the "special pair" pigments are strongly coupled, the degree of coupling among other BRC pigments has been thought to be relatively weak. Here we study the W(M250)V mutant BRC by two-color two-dimensional electronic spectroscopy to correlate changes in the Q x region with excitation of the Q y transitions. The resulting Q y-Q x cross-peaks provide a sensitive measure of the electronic interactions throughout the BRC pigment network and complement one-color 2D studies in which such interactions are often obscured by energy transfer and excited-state absorption signals. Our observations should motivate the refinement of electronic structure models of the BRC to facilitate improved understanding of the charge separation mechanism.
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Affiliation(s)
- Arkaprabha Konar
- Department of Physics , University of Michigan , Ann Arbor , Michigan 49109-1040 , United States
| | - Riley Sechrist
- Department of Physics , University of Michigan , Ann Arbor , Michigan 49109-1040 , United States
| | - Yin Song
- Department of Physics , University of Michigan , Ann Arbor , Michigan 49109-1040 , United States
| | - Veronica R Policht
- Department of Physics , University of Michigan , Ann Arbor , Michigan 49109-1040 , United States
| | - Philip D Laible
- Biosciences Division , Argonne National Laboratory , Argonne , Illinois 60439 , United States
| | - David F Bocian
- Department of Chemistry , University of California , Riverside , California 92521 , United States
| | - Dewey Holten
- Department of Chemistry , Washington University , St. Louis , Missouri 63130 , United States
| | - Christine Kirmaier
- Department of Chemistry , Washington University , St. Louis , Missouri 63130 , United States
| | - Jennifer P Ogilvie
- Department of Physics , University of Michigan , Ann Arbor , Michigan 49109-1040 , United States
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40
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Zhao Z, Zhang M, Hogle JM, Shih WM, Wagner G, Nasr ML. DNA-Corralled Nanodiscs for the Structural and Functional Characterization of Membrane Proteins and Viral Entry. J Am Chem Soc 2018; 140:10639-10643. [PMID: 30094995 PMCID: PMC6206850 DOI: 10.1021/jacs.8b04638] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Here we present a modular method for manufacturing large-sized nanodiscs using DNA-origami barrels as scaffolding corrals. Large-sized nanodiscs can be produced by first decorating the inside of DNA barrels with small lipid-bilayer nanodiscs, which open up when adding extra lipid to form large nanodiscs of diameters ∼45 or ∼70 nm as prescribed by the enclosing barrel dimension. Densely packed membrane protein arrays are then reconstituted within these large nanodiscs for potential structure determination. Furthermore, we demonstrate the potential of these nanodiscs as model membranes to study poliovirus entry.
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Affiliation(s)
- Zhao Zhao
- Wyss Institute for Biologically Inspired Engineering at Harvard , Boston , Massachusetts 02115 , United States
| | - Meng Zhang
- Department of Biological Chemistry and Molecular Pharmacology , Harvard Medical School , Boston , Massachusetts 02115 , United States
| | - James M Hogle
- Department of Biological Chemistry and Molecular Pharmacology , Harvard Medical School , Boston , Massachusetts 02115 , United States
| | - William M Shih
- Department of Biological Chemistry and Molecular Pharmacology , Harvard Medical School , Boston , Massachusetts 02115 , United States
- Wyss Institute for Biologically Inspired Engineering at Harvard , Boston , Massachusetts 02115 , United States
- Department of Cancer Biology , Dana-Farber Cancer Institute , Boston , Massachusetts 02215 , United States
| | - Gerhard Wagner
- Department of Biological Chemistry and Molecular Pharmacology , Harvard Medical School , Boston , Massachusetts 02115 , United States
| | - Mahmoud L Nasr
- Department of Biological Chemistry and Molecular Pharmacology , Harvard Medical School , Boston , Massachusetts 02115 , United States
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41
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Maragani R, Thomas MB, Misra R, D’Souza F. C3-Symmetric Positional Isomers of BODIPY Substituted Triazines: Synthesis and Excited State Properties. J Phys Chem A 2018; 122:4829-4837. [DOI: 10.1021/acs.jpca.8b02967] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ramesh Maragani
- Department of Chemistry, Indian Institute of Technology, Indore 453552, India
| | - Michael B. Thomas
- Department of Chemistry, University of North Texas, 1155 Union Circle, #305070, Denton, Texas 76203-5017, United States
| | - Rajneesh Misra
- Department of Chemistry, Indian Institute of Technology, Indore 453552, India
| | - Francis D’Souza
- Department of Chemistry, University of North Texas, 1155 Union Circle, #305070, Denton, Texas 76203-5017, United States
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42
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Deshmukh SS, Protheroe C, Ivanescu MA, Lag S, Kálmán L. Low potential manganese ions as efficient electron donors in native anoxygenic bacteria. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1859:227-233. [PMID: 29355486 DOI: 10.1016/j.bbabio.2018.01.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 12/20/2017] [Accepted: 01/16/2018] [Indexed: 12/14/2022]
Abstract
Systematic control over molecular driving forces is essential for understanding the natural electron transfer processes as well as for improving the efficiency of the artificial mimics of energy converting enzymes. Oxygen producing photosynthesis uniquely employs manganese ions as rapid electron donors. Introducing this attribute to anoxygenic photosynthesis may identify evolutionary intermediates and provide insights to the energetics of biological water oxidation. This work presents effective environmental methods that substantially and simultaneously tune the redox potentials of manganese ions and the cofactors of a photosynthetic enzyme from native anoxygenic bacteria without the necessity of genetic modification or synthesis. A spontaneous coordination with bis-tris propane lowered the redox potential of the manganese (II) to manganese (III) transition to an unusually low value (~400 mV) at pH 9.4 and allowed its binding to the bacterial reaction center. Binding to a novel buried binding site elevated the redox potential of the primary electron donor, a dimer of bacteriochlorophylls, by up to 92 mV also at pH 9.4 and facilitated the electron transfer that is able to compete with the wasteful charge recombination. These events impaired the function of the natural electron donor and made BTP-coordinated manganese a viable model for an evolutionary alternative.
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Affiliation(s)
| | | | | | - Sarah Lag
- Department of Physics, Concordia University, Montreal, QC, Canada
| | - László Kálmán
- Department of Physics, Concordia University, Montreal, QC, Canada.
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43
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Rancova O, Jankowiak R, Abramavicius D. Role of Bath Fluctuations in the Double-Excitation Manifold in Shaping the 2DES of Bacterial Reaction Centers at Low Temperature. J Phys Chem B 2018; 122:1348-1366. [DOI: 10.1021/acs.jpcb.7b08905] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Olga Rancova
- Institute
of Chemical Physics, Vilnius University, Sauletekio al 9-III, 10222 Vilnius, Lithuania
| | - Ryszard Jankowiak
- Department
of Chemistry and Department of Physics, Kansas State University, 213 CBC Building, Manhattan, Kansas 66506-0401, United States
| | - Darius Abramavicius
- Institute
of Chemical Physics, Vilnius University, Sauletekio al 9-III, 10222 Vilnius, Lithuania
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44
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Faries KM, Dylla NP, Hanson DK, Holten D, Laible PD, Kirmaier C. Manipulating the Energetics and Rates of Electron Transfer in Rhodobacter capsulatus Reaction Centers with Asymmetric Pigment Content. J Phys Chem B 2017; 121:6989-7004. [DOI: 10.1021/acs.jpcb.7b01389] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Kaitlyn M. Faries
- Department
of Chemistry, Washington University, St. Louis, Missouri 63130, United States
| | - Nicholas P. Dylla
- Biosciences Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Deborah K. Hanson
- Biosciences Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Dewey Holten
- Department
of Chemistry, Washington University, St. Louis, Missouri 63130, United States
| | - Philip D. Laible
- Biosciences Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Christine Kirmaier
- Department
of Chemistry, Washington University, St. Louis, Missouri 63130, United States
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45
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Mandal S, Carey AM, Locsin J, Gao BR, Williams JC, Allen JP, Lin S, Woodbury NW. Mechanism of Triplet Energy Transfer in Photosynthetic Bacterial Reaction Centers. J Phys Chem B 2017; 121:6499-6510. [DOI: 10.1021/acs.jpcb.7b03373] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Sarthak Mandal
- Center
for Innovations in Medicine, The Biodesign Institute at ASU, Arizona State University, Tempe, Arizona 85287, United States
| | - Anne-Marie Carey
- Center
for Innovations in Medicine, The Biodesign Institute at ASU, Arizona State University, Tempe, Arizona 85287, United States
| | - Joshua Locsin
- Center
for Innovations in Medicine, The Biodesign Institute at ASU, Arizona State University, Tempe, Arizona 85287, United States
| | | | - JoAnn C. Williams
- School
of Molecular Sciences, Arizona State University, Tempe, Arizona 85287−1604, United States
| | - James P. Allen
- School
of Molecular Sciences, Arizona State University, Tempe, Arizona 85287−1604, United States
| | - Su Lin
- Center
for Innovations in Medicine, The Biodesign Institute at ASU, Arizona State University, Tempe, Arizona 85287, United States
- School
of Molecular Sciences, Arizona State University, Tempe, Arizona 85287−1604, United States
| | - Neal W. Woodbury
- Center
for Innovations in Medicine, The Biodesign Institute at ASU, Arizona State University, Tempe, Arizona 85287, United States
- School
of Molecular Sciences, Arizona State University, Tempe, Arizona 85287−1604, United States
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46
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Shi Y, Yu J, Yu LJ, Wang P, Fu LM, Zhang JP, Wang-Otomo ZY. Dependence of the hydration status of bacterial light-harvesting complex 2 on polyol cosolvents. Photochem Photobiol Sci 2017; 16:795-807. [DOI: 10.1039/c6pp00270f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Tch. tepidumLH2 hydration correlates with water activity in water–polyol binary solvents as sensitively probed by near infrared electronic spectra and characteristic triplet carotenoid–bacteriochlorophyll interaction bands.
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Affiliation(s)
- Ying Shi
- Department of Chemistry
- Renmin University of China
- Beijing 1000872
- P. R. China
| | - Jie Yu
- Department of Chemistry
- Renmin University of China
- Beijing 1000872
- P. R. China
| | - Long-Jiang Yu
- Faculty of Science
- Ibaraki University
- Mito 310-8512
- Japan
| | - Peng Wang
- Department of Chemistry
- Renmin University of China
- Beijing 1000872
- P. R. China
| | - Li-Min Fu
- Department of Chemistry
- Renmin University of China
- Beijing 1000872
- P. R. China
| | - Jian-Ping Zhang
- Department of Chemistry
- Renmin University of China
- Beijing 1000872
- P. R. China
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47
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Nalepa A, Malferrari M, Lubitz W, Venturoli G, Möbius K, Savitsky A. Local water sensing: water exchange in bacterial photosynthetic reaction centers embedded in a trehalose glass studied using multiresonance EPR. Phys Chem Chem Phys 2017; 19:28388-28400. [DOI: 10.1039/c7cp03942e] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Pulsed EPR spectroscopies and isotope labeled water are applied to detect and quantify the local water in a bacterial reaction center embedded into a trehalose glass.
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Affiliation(s)
- Anna Nalepa
- Max-Planck-Institut für Chemische Energiekonversion
- D-45470 Mülheim an der Ruhr
- Germany
| | - Marco Malferrari
- Laboratorio di Biochimica e Biofisica
- Dipartimento di Farmacia e Biotecnologie
- FaBiT
- Università di Bologna
- I-40126 Bologna
| | - Wolfgang Lubitz
- Max-Planck-Institut für Chemische Energiekonversion
- D-45470 Mülheim an der Ruhr
- Germany
| | - Giovanni Venturoli
- Laboratorio di Biochimica e Biofisica
- Dipartimento di Farmacia e Biotecnologie
- FaBiT
- Università di Bologna
- I-40126 Bologna
| | - Klaus Möbius
- Max-Planck-Institut für Chemische Energiekonversion
- D-45470 Mülheim an der Ruhr
- Germany
- Department of Physics
- Free University Berlin
| | - Anton Savitsky
- Max-Planck-Institut für Chemische Energiekonversion
- D-45470 Mülheim an der Ruhr
- Germany
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48
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Zheng F, Jin M, Mančal T, Zhao Y. Study of Electronic Structures and Pigment–Protein Interactions in the Reaction Center of Thermochromatium tepidum with a Dynamic Environment. J Phys Chem B 2016; 120:10046-10058. [DOI: 10.1021/acs.jpcb.6b06628] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Fulu Zheng
- Division
of Materials Science, Nanyang Technological University, Singapore 639798, Singapore
| | - Mengting Jin
- Division
of Materials Science, Nanyang Technological University, Singapore 639798, Singapore
| | - Tomáš Mančal
- Faculty
of Mathematics and Physics, Charles University in Prague, Ke Karlovu
5, 121 16 Prague
2, Czech Republic
| | - Yang Zhao
- Division
of Materials Science, Nanyang Technological University, Singapore 639798, Singapore
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49
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Löhner A, Ashraf K, Cogdell RJ, Köhler J. Fluorescence-excitation and Emission Spectroscopy on Single FMO Complexes. Sci Rep 2016; 6:31875. [PMID: 27545197 PMCID: PMC4992959 DOI: 10.1038/srep31875] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 07/29/2016] [Indexed: 12/26/2022] Open
Abstract
In green-sulfur bacteria sunlight is absorbed by antenna structures termed chlorosomes, and transferred to the RC via the Fenna-Matthews-Olson (FMO) complex. FMO consists of three monomers arranged in C3 symmetry where each monomer accommodates eight Bacteriochlorophyll a (BChl a) molecules. It was the first pigment-protein complex for which the structure has been determined with high resolution and since then this complex has been the subject of numerous studies both experimentally and theoretically. Here we report about fluorescence-excitation spectroscopy as well as emission spectroscopy from individual FMO complexes at low temperatures. The individual FMO complexes are subjected to very fast spectral fluctuations smearing out any possible different information from the ensemble data that were recorded under the same experimental conditions. In other words, on the time scales that are experimentally accessible by single-molecule techniques, the FMO complex exhibits ergodic behaviour.
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Affiliation(s)
- Alexander Löhner
- Experimental Physics IV and Bayreuth Institute for Macromolecular Research (BIMF), University of Bayreuth, Germany
| | - Khuram Ashraf
- Institute of Molecular, Cell & Systems Biology, College of Medical Veterinary and Life Sciences, University of Glasgow, United Kingdom
| | - Richard J. Cogdell
- Institute of Molecular, Cell & Systems Biology, College of Medical Veterinary and Life Sciences, University of Glasgow, United Kingdom
| | - Jürgen Köhler
- Experimental Physics IV and Bayreuth Institute for Macromolecular Research (BIMF), University of Bayreuth, Germany
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50
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Dylla NP, Faries KM, Wyllie RM, Swenson AM, Hanson DK, Holten D, Kirmaier C, Laible PD. Species differences in unlocking B‐side electron transfer in bacterial reaction centers. FEBS Lett 2016; 590:2515-26. [DOI: 10.1002/1873-3468.12264] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 06/13/2016] [Indexed: 11/09/2022]
Affiliation(s)
| | | | - Ryan M. Wyllie
- Biosciences Division Argonne National Laboratory Lemont IL USA
| | | | | | - Dewey Holten
- Department of Chemistry Washington University St. Louis MO USA
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