1
|
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.
Collapse
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.
| |
Collapse
|
2
|
Cherepanov D, Aybush A, Johnson TW, Shelaev I, Gostev F, Mamedov M, Nadtochenko V, Semenov A. Inverted region in the reaction of the quinone reduction in the A 1-site of photosystem I from cyanobacteria. PHOTOSYNTHESIS RESEARCH 2024; 159:115-131. [PMID: 37093503 DOI: 10.1007/s11120-023-01020-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Accepted: 04/13/2023] [Indexed: 05/03/2023]
Abstract
Photosystem I from the menB strain of Synechocystis sp. PCC 6803 containing foreign quinones in the A1 sites was used for studying the primary steps of electron transfer by pump-probe femtosecond laser spectroscopy. The free energy gap (- ΔG) of electron transfer between the reduced primary acceptor A0 and the quinones bound in the A1 site varied from 0.12 eV for the low-potential 1,2-diamino-anthraquinone to 0.88 eV for the high-potential 2,3-dichloro-1,4-naphthoquinone, compared to 0.5 eV for the native phylloquinone. It was shown that the kinetics of charge separation between the special pair chlorophyll P700 and the primary acceptor A0 was not affected by quinone substitutions, whereas the rate of A0 → A1 electron transfer was sensitive to the redox-potential of quinones: the decrease of - ΔG by 400 meV compared to the native phylloquinone resulted in a ~ fivefold slowing of the reaction The presence of the asymmetric inverted region in the ΔG dependence of the reaction rate indicates that the electron transfer in photosystem I is controlled by nuclear tunneling and should be treated in terms of quantum electron-phonon interactions. A three-mode implementation of the multiphonon model, which includes modes around 240 cm-1 (large-scale protein vibrations), 930 cm-1 (out-of-plane bending of macrocycles and protein backbone vibrations), and 1600 cm-1 (double bonds vibrations) was applied to rationalize the observed dependence. The modes with a frequency of at least 1600 cm-1 make the predominant contribution to the reorganization energy, while the contribution of the "classical" low-frequency modes is only 4%.
Collapse
Affiliation(s)
- Dmitry Cherepanov
- N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, Kosygina Street 4, Moscow, Russia, 119991.
- A.N. Belozersky Institute of Physical-Chemical Biology, Lomonosov Moscow State University, Leninskye Gory 1, bldg 40, Moscow, Russia, 119992.
| | - Arseny Aybush
- N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, Kosygina Street 4, Moscow, Russia, 119991
| | - T Wade Johnson
- Department of Chemistry, Susquehanna University, 514 University Ave., Selinsgrove, PA, 17870, USA
| | - Ivan Shelaev
- N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, Kosygina Street 4, Moscow, Russia, 119991
| | - Fedor Gostev
- N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, Kosygina Street 4, Moscow, Russia, 119991
| | - Mahir Mamedov
- A.N. Belozersky Institute of Physical-Chemical Biology, Lomonosov Moscow State University, Leninskye Gory 1, bldg 40, Moscow, Russia, 119992
| | - Victor Nadtochenko
- N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, Kosygina Street 4, Moscow, Russia, 119991
- Department of Chemistry, Lomonosov Moscow State University, Leninskiye Gory 1-3, Moscow, Russia, 119991
| | - Alexey Semenov
- N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, Kosygina Street 4, Moscow, Russia, 119991.
- A.N. Belozersky Institute of Physical-Chemical Biology, Lomonosov Moscow State University, Leninskye Gory 1, bldg 40, Moscow, Russia, 119992.
| |
Collapse
|
3
|
Williams JC, Faillace MS, Gonzalez EJ, Dominguez RE, Knappenberger K, Heredia DA, Moore TA, Moore AL, Allen JP. Mn-porphyrins in a four-helix bundle participate in photo-induced electron transfer with a bacterial reaction center. PHOTOSYNTHESIS RESEARCH 2023:10.1007/s11120-023-01051-9. [PMID: 37910331 DOI: 10.1007/s11120-023-01051-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 09/18/2023] [Indexed: 11/03/2023]
Abstract
Hybrid complexes incorporating synthetic Mn-porphyrins into an artificial four-helix bundle domain of bacterial reaction centers created a system to investigate new electron transfer pathways. The reactions were initiated by illumination of the bacterial reaction centers, whose primary photochemistry involves electron transfer from the bacteriochlorophyll dimer through a series of electron acceptors to the quinone electron acceptors. Porphyrins with diphenyl, dimesityl, or fluorinated substituents were synthesized containing either Mn or Zn. Electrochemical measurements revealed potentials for Mn(III)/Mn(II) transitions that are ~ 0.4 V higher for the fluorinated Mn-porphyrins than the diphenyl and dimesityl Mn-porphyrins. The synthetic porphyrins were introduced into the proteins by binding to a four-helix bundle domain that was genetically fused to the reaction center. Light excitation of the bacteriochlorophyll dimer of the reaction center resulted in new derivative signals, in the 400 to 450 nm region of light-minus-dark spectra, that are consistent with oxidation of the fluorinated Mn(II) porphyrins and reduction of the diphenyl and dimesityl Mn(III) porphyrins. These features recovered in the dark and were not observed in the Zn(II) porphyrins. The amplitudes of the signals were dependent upon the oxidation/reduction midpoint potentials of the bacteriochlorophyll dimer. These results are interpreted as photo-induced charge-separation processes resulting in redox changes of the Mn-porphyrins, demonstrating the utility of the hybrid artificial reaction center system to establish design guidelines for novel electron transfer reactions.
Collapse
Affiliation(s)
- J C Williams
- School of Molecular Sciences, Arizona State University, Tempe, AZ, 85287, USA
| | - M S Faillace
- School of Molecular Sciences, Arizona State University, Tempe, AZ, 85287, USA
| | - E J Gonzalez
- School of Molecular Sciences, Arizona State University, Tempe, AZ, 85287, USA
| | - R E Dominguez
- School of Molecular Sciences, Arizona State University, Tempe, AZ, 85287, USA
| | - K Knappenberger
- School of Molecular Sciences, Arizona State University, Tempe, AZ, 85287, USA
| | - D A Heredia
- School of Molecular Sciences, Arizona State University, Tempe, AZ, 85287, USA
| | - T A Moore
- School of Molecular Sciences, Arizona State University, Tempe, AZ, 85287, USA
| | - A L Moore
- School of Molecular Sciences, Arizona State University, Tempe, AZ, 85287, USA
| | - J P Allen
- School of Molecular Sciences, Arizona State University, Tempe, AZ, 85287, USA.
| |
Collapse
|
4
|
Samaei A, Deshmukh SS, Protheroe C, Nyéki S, Tremblay-Ethier RA, Kálmán L. Photoactivation and conformational gating for manganese binding and oxidation in bacterial reaction centers. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2023; 1864:148928. [PMID: 36216075 DOI: 10.1016/j.bbabio.2022.148928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 09/26/2022] [Accepted: 10/03/2022] [Indexed: 11/05/2022]
Abstract
The influence of illumination history of native bacterial reaction centers (BRCs) on the ability of binding and photo-induced oxidation of manganous ions was investigated in the pH range between 8.0 and 9.4. Binding of manganous ions to a buried site required 6 to 11-fold longer incubation periods, depending on the pH, in dark-adapted BRCs than in BRCs that were previously illuminated prior to manganese binding. The intrinsic electron transfer from the bound manganese ion to the photo-oxidized primary electron donor was found to be limited by a 2 to 5-fold slower precursor conformational step in the dark-adapted samples for the same pH range. The conformational gating could be eliminated by photoactivation, namely if the BRCs were illuminated prior to binding. Unlike in Photosystem II, photoactivation in BRCs did not involve cluster assembly. Photoactivation with manganese already bound was only possible at elevated detergent concentration. In addition, also exclusively in dark-adapted BRCs, a marked breaking point in the Arrhenius-plot was discovered around 15 °C at pH 9.4 indicating a change in the reaction mechanism, most likely caused by the change of orientation of the 2-acetyl group of the inactive bacteriochlorophyll monomer located near the manganese binding site.
Collapse
Affiliation(s)
- Ali Samaei
- Department of Physics, Concordia University, Montreal, QC, Canada
| | | | | | - Sarah Nyéki
- Department of Physics, Concordia University, Montreal, QC, Canada
| | | | - László Kálmán
- Department of Physics, Concordia University, Montreal, QC, Canada.
| |
Collapse
|
5
|
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.
Collapse
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
| |
Collapse
|
6
|
Dubas K, Szewczyk S, Białek R, Burdziński G, Jones MR, Gibasiewicz K. Antagonistic Effects of Point Mutations on Charge Recombination and a New View of Primary Charge Separation in Photosynthetic Proteins. J Phys Chem B 2021; 125:8742-8756. [PMID: 34328746 PMCID: PMC8389993 DOI: 10.1021/acs.jpcb.1c03978] [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] [Indexed: 11/29/2022]
Abstract
![]()
Light-induced electron-transfer
reactions were investigated in
wild-type and three mutant Rhodobacter sphaeroides reaction centers with the secondary electron acceptor (ubiquinone
QA) either removed or permanently reduced. Under such conditions,
charge separation between the primary electron donor (bacteriochlorophyll
dimer, P) and the electron acceptor (bacteriopheophytin, HA) was followed by P+HA– →
PHA charge recombination. Two reaction centers were used
that had different single amino-acid mutations that brought about
either a 3-fold acceleration in charge recombination compared to that
in the wild-type protein, or a 3-fold deceleration. In a third mutant
in which the two single amino-acid mutations were combined, charge
recombination was similar to that in the wild type. In all cases,
data from transient absorption measurements were analyzed using similar
models. The modeling included the energetic relaxation of the charge-separated
states caused by protein dynamics and evidenced the appearance of
an intermediate charge-separated state, P+BA–, with BA being the bacteriochlorophyll
located between P and HA. In all cases, mixing of the states
P+BA– and P+HA– was observed and explained in terms of
electron delocalization over BA and HA. This
delocalization, together with picosecond protein relaxation, underlies
a new view of primary charge separation in photosynthesis.
Collapse
Affiliation(s)
- K Dubas
- Faculty of Physics, Adam Mickiewicz University, ul. Uniwersytetu Poznanskiego 2, 61-614 Poznań, Poland.,Department of Optometry, Poznan University of Medical Sciences, ul. Rokietnicka 5d, 60-806 Poznań, Poland
| | - S Szewczyk
- Faculty of Physics, Adam Mickiewicz University, ul. Uniwersytetu Poznanskiego 2, 61-614 Poznań, Poland
| | - R Białek
- Faculty of Physics, Adam Mickiewicz University, ul. Uniwersytetu Poznanskiego 2, 61-614 Poznań, Poland
| | - G Burdziński
- Faculty of Physics, Adam Mickiewicz University, ul. Uniwersytetu Poznanskiego 2, 61-614 Poznań, Poland
| | - M R Jones
- School of Biochemistry, Medical Sciences Building, University of Bristol, University Walk, Bristol, BS8 1TD, U.K
| | - K Gibasiewicz
- Faculty of Physics, Adam Mickiewicz University, ul. Uniwersytetu Poznanskiego 2, 61-614 Poznań, Poland
| |
Collapse
|
7
|
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.
Collapse
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.
| |
Collapse
|
8
|
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.
Collapse
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
| |
Collapse
|
9
|
Jalviste E, Timpmann K, Chenchiliyan M, Kangur L, Jones MR, Freiberg A. High-Pressure Modulation of Primary Photosynthetic Reactions. J Phys Chem B 2020; 124:718-726. [PMID: 31917566 DOI: 10.1021/acs.jpcb.9b09342] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Photochemical charge separation is key to biological solar energy conversion. Although many features of this highly quantum-efficient process have been described, others remain poorly understood. Herein, ultrafast fluorescence barospectroscopy is used for the first time to obtain insights into the mechanism of primary charge separation in a YM210W mutant bacterial reaction center under novel surrounding modulating conditions. Over a range of applied hydrostatic pressures reaching 10 kbar, the rate of primary charge separation monotonously increased and that of the electron transfer to secondary acceptor decreased. While the inferred free energy gap for charge separation generally narrowed with increasing pressure, a pressure-induced break of a protein-cofactor hydrogen bond observed at ∼2 kbar significantly (by 219 cm-1 or 27 meV) increased this gap, resulting in a drop in fluorescence. The findings strongly favor a model for primary charge separation that incorporates charge recombination and restoration of the excited primary pair state, over a purely sequential model. We show that the main reason for the almost threefold acceleration of the primary electron transfer rate is the pressure-induced increase of the electronic coupling energy, rather than a change of activation energy. We also conclude that across all applied pressures, the primary electron transfer in the mutant reaction center studied can be considered nonadiabatic, normal region, and thermally activated.
Collapse
Affiliation(s)
- Erko Jalviste
- Institute of Physics , University of Tartu , W. Ostwald Str. 1 , Tartu 50411 , Estonia
| | - Kõu Timpmann
- Institute of Physics , University of Tartu , W. Ostwald Str. 1 , Tartu 50411 , Estonia
| | - Manoop Chenchiliyan
- Institute of Physics , University of Tartu , W. Ostwald Str. 1 , Tartu 50411 , Estonia
| | - Liina Kangur
- Institute of Physics , University of Tartu , W. Ostwald Str. 1 , Tartu 50411 , Estonia
| | - Michael R Jones
- School of Biochemistry , University of Bristol , Biomedical Sciences Building, University Walk , Bristol BS8 1TD , U.K
| | - Arvi Freiberg
- Institute of Physics , University of Tartu , W. Ostwald Str. 1 , Tartu 50411 , Estonia.,Institute of Molecular and Cell Biology , University of Tartu , Riia 23 , Tartu 51010 , Estonia.,Estonian Academy of Sciences , Kohtu 6 , 10130 Tallinn , Estonia
| |
Collapse
|
10
|
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.
Collapse
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.
| |
Collapse
|
11
|
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
| |
Collapse
|
12
|
Pan J, Saer R, Lin S, Beatty JT, Woodbury NW. Electron Transfer in Bacterial Reaction Centers with the Photoactive Bacteriopheophytin Replaced by a Bacteriochlorophyll through Coordinating Ligand Substitution. Biochemistry 2016; 55:4909-18. [DOI: 10.1021/acs.biochem.6b00317] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jie Pan
- The
Biodesign Institute at Arizona State University, Arizona State University, Tempe, Arizona 85287-5201, United States
| | - Rafael Saer
- Department
of Microbiology and Immunology, The University of British Columbia, 2350 Health Sciences Mall, Vancouver, British Columbia, Canada V6T 1Z3
| | - Su Lin
- The
Biodesign Institute at Arizona State University, Arizona State University, Tempe, Arizona 85287-5201, United States
- School
of Molecular Sciences, Arizona State University, Tempe, Arizona 85287-1604, United States
| | - J. Thomas Beatty
- Department
of Microbiology and Immunology, The University of British Columbia, 2350 Health Sciences Mall, Vancouver, British Columbia, Canada V6T 1Z3
| | - Neal W. Woodbury
- The
Biodesign Institute at Arizona State University, Arizona State University, Tempe, Arizona 85287-5201, United States
- School
of Molecular Sciences, Arizona State University, Tempe, Arizona 85287-1604, United States
| |
Collapse
|
13
|
Gibasiewicz K, Białek R, Pajzderska M, Karolczak J, Burdziński G, Jones MR, Brettel K. Weak temperature dependence of P (+) H A (-) recombination in mutant Rhodobacter sphaeroides reaction centers. PHOTOSYNTHESIS RESEARCH 2016; 128:243-258. [PMID: 26942583 PMCID: PMC4877430 DOI: 10.1007/s11120-016-0239-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 02/24/2016] [Indexed: 06/05/2023]
Abstract
In contrast with findings on the wild-type Rhodobacter sphaeroides reaction center, biexponential P (+) H A (-) → PH A charge recombination is shown to be weakly dependent on temperature between 78 and 298 K in three variants with single amino acids exchanged in the vicinity of primary electron acceptors. These mutated reaction centers have diverse overall kinetics of charge recombination, spanning an average lifetime from ~2 to ~20 ns. Despite these differences a protein relaxation model applied previously to wild-type reaction centers was successfully used to relate the observed kinetics to the temporal evolution of the free energy level of the state P (+) H A (-) relative to P (+) B A (-) . We conclude that the observed variety in the kinetics of charge recombination, together with their weak temperature dependence, is caused by a combination of factors that are each affected to a different extent by the point mutations in a particular mutant complex. These are as follows: (1) the initial free energy gap between the states P (+) B A (-) and P (+) H A (-) , (2) the intrinsic rate of P (+) B A (-) → PB A charge recombination, and (3) the rate of protein relaxation in response to the appearance of the charge separated states. In the case of a mutant which displays rapid P (+) H A (-) recombination (ELL), most of this recombination occurs in an unrelaxed protein in which P (+) B A (-) and P (+) H A (-) are almost isoenergetic. In contrast, in a mutant in which P (+) H A (-) recombination is relatively slow (GML), most of the recombination occurs in a relaxed protein in which P (+) H A (-) is much lower in energy than P (+) H A (-) . The weak temperature dependence in the ELL reaction center and a YLH mutant was modeled in two ways: (1) by assuming that the initial P (+) B A (-) and P (+) H A (-) states in an unrelaxed protein are isoenergetic, whereas the final free energy gap between these states following the protein relaxation is large (~250 meV or more), independent of temperature and (2) by assuming that the initial and final free energy gaps between P (+) B A (-) and P (+) H A (-) are moderate and temperature dependent. In the case of the GML mutant, it was concluded that the free energy gap between P (+) B A (-) and P (+) H A (-) is large at all times.
Collapse
Affiliation(s)
- Krzysztof Gibasiewicz
- Department of Physics, Adam Mickiewicz University, ul. Umultowska 85, 61-614, Poznań, Poland.
| | - Rafał Białek
- Department of Physics, Adam Mickiewicz University, ul. Umultowska 85, 61-614, Poznań, Poland
| | - Maria Pajzderska
- Department of Physics, Adam Mickiewicz University, ul. Umultowska 85, 61-614, Poznań, Poland
| | - Jerzy Karolczak
- Department of Physics, Adam Mickiewicz University, ul. Umultowska 85, 61-614, Poznań, Poland
- Center for Ultrafast Laser Spectroscopy, A. Mickiewicz University, ul. Umultowska 85, 61-614, Poznań, Poland
| | - Gotard Burdziński
- Department of Physics, Adam Mickiewicz University, ul. Umultowska 85, 61-614, Poznań, Poland
| | - Michael R Jones
- School of Biochemistry, Medical Sciences Building, University of Bristol, University Walk, Bristol, BS8 1TD, UK
| | - Klaus Brettel
- Laboratoire Mécanismes Fondamentaux de la Bioénergétique, UMR 8221, CEA - iBiTec-S, CNRS, Université Paris Sud, 91191, Gif-Sur-Yvette, France
| |
Collapse
|
14
|
Milanovsky GE, Shuvalov VA, Semenov AY, Cherepanov DA. Elastic Vibrations in the Photosynthetic Bacterial Reaction Center Coupled to the Primary Charge Separation: Implications from Molecular Dynamics Simulations and Stochastic Langevin Approach. J Phys Chem B 2015; 119:13656-67. [PMID: 26148224 DOI: 10.1021/acs.jpcb.5b03036] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Primary electron transfer reactions in the bacterial reaction center are difficult for theoretical explication: the reaction kinetics, almost unalterable over a wide range of temperature and free energy changes, revealed oscillatory features observed initially by Shuvalov and coauthors (1997, 2002). Here the reaction mechanism was studied by molecular dynamics and analyzed within a phenomenological Langevin approach. The spectral function of polarization around the bacteriochlorophyll special pair PLPM and the dielectric response upon the formation of PL(+)PM(-) dipole within the special pair were calculated. The system response was approximated by Langevin oscillators; the respective frequencies, friction, and energy coupling coefficients were determined. The protein dynamics around PL and PM were distinctly asymmetric. The polarization around PL included slow modes with the frequency 30-80 cm(-1) and the total amplitude of 130 mV. Two main low-frequency modes of protein response around PM had frequencies of 95 and 155 cm(-1) and the total amplitude of 30 mV. In addition, a slowly damping mode with the frequency of 118 cm(-1) and the damping time >1.1 ps was coupled to the formation of PL(+)PM(-) dipole. It was attributed to elastic vibrations of α-helices in the vicinity of PLPM. The proposed trapping of P excitation energy in the form of the elastic vibrations can rationalize the observed properties of the primary electron transfer reactions, namely, the unusual temperature and ΔG dependences, the oscillating phenomena in kinetics, and the asymmetry of the charge separation reactions.
Collapse
Affiliation(s)
- Georgy E Milanovsky
- A. N. Belozersky Institute of Physical-Chemical Biology, Moscow State University , Leninskiye Gory, 119992 Moscow, Russia
| | - Vladimir A Shuvalov
- A. N. Belozersky Institute of Physical-Chemical Biology, Moscow State University , Leninskiye Gory, 119992 Moscow, Russia.,N. N. Semenov Institute of Chemical Physics, Russian Academy of Sciences , Kosygina st., 4, 117977 Moscow, Russia
| | - Alexey Yu Semenov
- A. N. Belozersky Institute of Physical-Chemical Biology, Moscow State University , Leninskiye Gory, 119992 Moscow, Russia.,N. N. Semenov Institute of Chemical Physics, Russian Academy of Sciences , Kosygina st., 4, 117977 Moscow, Russia
| | - Dmitry A Cherepanov
- A. N. Belozersky Institute of Physical-Chemical Biology, Moscow State University , Leninskiye Gory, 119992 Moscow, Russia.,A. N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences , 31, Leninsky Prospect, 119071 Moscow, Russia
| |
Collapse
|
15
|
Zhu J, van Stokkum IHM, Paparelli L, Jones MR, Groot ML. Early bacteriopheophytin reduction in charge separation in reaction centers of Rhodobacter sphaeroides. Biophys J 2014; 104:2493-502. [PMID: 23746522 DOI: 10.1016/j.bpj.2013.04.026] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Revised: 04/11/2013] [Accepted: 04/12/2013] [Indexed: 11/16/2022] Open
Abstract
A question at the forefront of biophysical sciences is, to what extent do quantum effects and protein conformational changes play a role in processes such as biological sensing and energy conversion? At the heart of photosynthetic energy transduction lie processes involving ultrafast energy and electron transfers among a small number of tetrapyrrole pigments embedded in the interior of a protein. In the purple bacterial reaction center (RC), a highly efficient ultrafast charge separation takes place between a pair of bacteriochlorophylls: an accessory bacteriochlorophyll (B) and bacteriopheophytin (H). In this work, we applied ultrafast spectroscopy in the visible and near-infrared spectral region to Rhodobacter sphaeroides RCs to accurately track the timing of the electron on BA and HA via the appearance of the BA and HA anion bands. We observed an unexpectedly early rise of the HA⁻ band that challenges the accepted simple picture of stepwise electron transfer with 3 ps and 1 ps time constants. The implications for the mechanism of initial charge separation in bacterial RCs are discussed in terms of a possible adiabatic electron transfer step between BA and HA, and the effect of protein conformation on the electron transfer rate.
Collapse
Affiliation(s)
- Jingyi Zhu
- Department of Physics, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands
| | | | | | | | | |
Collapse
|
16
|
Proton Binding Is Part of Protein Relaxation of Flash-Excited Reaction Center from Photosynthetic BacteriaRhodobacter sphaeroides. Isr J Chem 2013. [DOI: 10.1002/ijch.199900050] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
17
|
Gibasiewicz K, Pajzderska M, Dobek A, Karolczak J, Burdziński G, Brettel K, Jones MR. Analysis of the temperature-dependence of P(+)HA(-) charge recombination in the Rhodobacter sphaeroides reaction center suggests nanosecond temperature-independent protein relaxation. Phys Chem Chem Phys 2013; 15:16321-33. [PMID: 23999896 DOI: 10.1039/c3cp44187c] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The temperature dependence of charge recombination of the pair P(+)HA(-) in isolated reaction centers from the purple bacterium Rhodobacter sphaeroides with prereduced quinone QA was studied by sub-nanosecond to microsecond time-scale transient absorption. Overall, the kinetics slowed down substantially upon cooling from room temperature to ∼200 K, and then remained virtually unchanged down to 77 K, indicating the coexistence of two competitive pathways of charge recombination, a thermally-activated pathway appearing only above ~200 K and a temperature-independent pathway. In our modelling, the thermally activated pathway includes an uphill electron transfer from HA(-) to BA(-) leading to transient formation of the state P(+)BA(-), whereas the temperature-independent pathway is due to direct downhill electron transfer from HA(-) to P(+). At all temperatures studied, the kinetics could be approximated by a four-component decay. Detailed analysis of the lifetimes and amplitudes of particular phases over the range of temperatures suggests that the kinetically resolved phases reveal the consecutive appearance of three conformational states characterized by an increasing free energy gap between the states P(+)BA(-) and P(+)HA(-). The initial gap between these states was estimated to be only ~8 meV, the intermediate gap being ~92 meV, and the final gap ~135 meV, with no dependence on temperature. It was also calculated through a very straightforward approach that the relaxation process from the initial to the intermediate state occurs within 0.6 ± 0.1 ns, whereas the second step of relaxation from the intermediate to the final state takes 11 ± 2 ns. Both phases of the protein relaxation process are essentially temperature-independent. Possible alternative models to describe the experimental data that cannot be definitely excluded are also discussed.
Collapse
Affiliation(s)
- Krzysztof Gibasiewicz
- Department of Physics, Adam Mickiewicz University, ul. Umultowska 85, 61-614 Poznań, Poland.
| | | | | | | | | | | | | |
Collapse
|
18
|
Pan J, Saer RG, Lin S, Guo Z, Beatty JT, Woodbury NW. The Protein Environment of the Bacteriopheophytin Anion Modulates Charge Separation and Charge Recombination in Bacterial Reaction Centers. J Phys Chem B 2013; 117:7179-89. [DOI: 10.1021/jp400132k] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jie Pan
- The Biodesign
Institute at Arizona
State University, Arizona State University, Tempe, Arizona 85287-5201, United States
| | - Rafael G. Saer
- Department of Microbiology and
Immunology, The University of British Columbia, 2350 Health Sciences Mall, Vancouver, British Columbia, Canada
V6T 1Z3
| | - Su Lin
- The Biodesign
Institute at Arizona
State University, Arizona State University, Tempe, Arizona 85287-5201, United States
- Department of Chemistry and
Biochemistry, Arizona State University,
Tempe, Arizona 85287-1604, United States
| | - Zhi Guo
- The Biodesign
Institute at Arizona
State University, Arizona State University, Tempe, Arizona 85287-5201, United States
| | - J. Thomas Beatty
- Department of Microbiology and
Immunology, The University of British Columbia, 2350 Health Sciences Mall, Vancouver, British Columbia, Canada
V6T 1Z3
| | - Neal W. Woodbury
- The Biodesign
Institute at Arizona
State University, Arizona State University, Tempe, Arizona 85287-5201, United States
- Department of Chemistry and
Biochemistry, Arizona State University,
Tempe, Arizona 85287-1604, United States
| |
Collapse
|
19
|
Guo Z, Woodbury NW, Pan J, Lin S. Protein dielectric environment modulates the electron-transfer pathway in photosynthetic reaction centers. Biophys J 2013. [PMID: 23199926 DOI: 10.1016/j.bpj.2012.09.027] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The replacement of tyrosine by aspartic acid at position M210 in the photosynthetic reaction center of Rhodobacter sphaeroides results in the generation of a fast charge recombination pathway that is not observed in the wild-type. Apparently, the initially formed charge-separated state (cation of the special pair, P, and anion of the A-side bacteriopheophytin, H(A)) can decay rapidly via recombination through the neighboring bacteriochlorophyll (B(A)) soon after formation. The charge-separated state then relaxes over tens of picoseconds and recombination slows to the hundreds-of-picoseconds or nanosecond timescale. This dielectric relaxation results in a time-dependent blue shift of B(A)(-) absorption, which can be monitored using transient absorbance measurements. Protein dynamics also appear to modulate the electron transfer between H(A) and the next electron carrier, Q(A) (a ubiquinone). The kinetics of this reaction are complex in the mutant, requiring two kinetic terms, and the spectra associated with the two terms are distinct; a red shift of the H(A) ground-state bleaching is observed between the shorter and longer H(A)-to-Q(A) electron-transfer phases. The kinetics appears to be pH-independent, suggesting a negligible contribution of static heterogeneity originating from protonation/deprotonation in the ground state. A dynamic model based on the energy levels of the two early charge-separated states, P(+)B(A)(-) and P(+)H(A)(-), has been developed in which the energetics of these states is modulated by fast protein dielectric relaxations and this in turn alters both the kinetic complexity of the reaction and the reaction pathway.
Collapse
Affiliation(s)
- Zhi Guo
- The Biodesign Institute at Arizona State University, Tempe, Arizona, USA
| | | | | | | |
Collapse
|
20
|
Gibasiewicz K, Pajzderska M, Dobek A, Brettel K, Jones MR. Analysis of the kinetics of P+ HA- recombination in membrane-embedded wild-type and mutant Rhodobacter sphaeroides reaction centers between 298 and 77 K indicates that the adjacent negatively charged QA ubiquinone modulates the free energy of P+ HA- and may influence the rate of the protein dielectric response. J Phys Chem B 2013; 117:11112-23. [PMID: 23477295 DOI: 10.1021/jp4011235] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Time-resolved spectroscopic studies of recombination of the P(+)HA(-) radical pair in photosynthetic reaction centers (RCs) from Rhodobacter sphaeroides give an opportunity to study protein dynamics triggered by light and occurring over the lifetime of P(+)HA(-). The state P(+)HA(-) is formed after the ultrafast light-induced electron transfer from the primary donor pair of bacteriochlorophylls (P) to the acceptor bacteriopheophytin (HA). In order to increase the lifetime of this state, and thus increase the temporal window for the examination of protein dynamics, it is possible to block forward electron transfer from HA(-) to the secondary electron acceptor QA. In this contribution, the dynamics of P(+)HA(-) recombination were compared at a range of temperatures from 77 K to room temperature, electron transfer from HA(-) to QA being blocked either by prereduction of QA or by genetic removal of QA. The observed P(+)HA(-) charge recombination was significantly slower in the QA-deficient RCs, and in both types of complexes, lowering the temperature from RT to 77 K led to a slowing of charge recombination. The effects are explained in the frame of a model in which charge recombination occurs via competing pathways, one of which is thermally activated and includes transient formation of a higher-energy state, P(+)BA(-). An internal electrostatic field supplied by the negative charge on QA increases the free energy levels of the state P(+)HA(-), thus decreasing its energetic distance to the state P(+)BA(-). In addition, the dielectric response of the protein environment to the appearance of the state P(+)HA(-) is accelerated from ∼50-100 ns in the QA-deficient mutant RCs to ∼1-16 ns in WT RCs with a negatively charged QA(-). In both cases, the temperature dependence of the protein dynamics is weak.
Collapse
Affiliation(s)
- Krzysztof Gibasiewicz
- Department of Physics, Adam Mickiewicz University , ul. Umultowska 85, 61-614 Poznań, Poland
| | | | | | | | | |
Collapse
|
21
|
Carter B, Boxer SG, Holten D, Kirmaier C. Photochemistry of a Bacterial Photosynthetic Reaction Center Missing the Initial Bacteriochlorophyll Electron Acceptor. J Phys Chem B 2012; 116:9971-82. [DOI: 10.1021/jp305276m] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Brett Carter
- 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
| | - Dewey Holten
- Department of Chemistry, Washington University, St. Louis, Missouri
63130-4899, United States
| | - Christine Kirmaier
- Department of Chemistry, Washington University, St. Louis, Missouri
63130-4899, United States
| |
Collapse
|
22
|
Wang H, Hao Y, Jiang Y, Lin S, Woodbury NW. Role of Protein Dynamics in Guiding Electron-Transfer Pathways in Reaction Centers from Rhodobacter sphaeroides. J Phys Chem B 2011; 116:711-7. [DOI: 10.1021/jp211702b] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Haiyu Wang
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China
- The Biodesign Institute, and Department of Chemistry and Biochemistry, Arizona State University, 1001 McAllister Ave., Tempe, Arizona 85287, United States
| | - Yawei Hao
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China
| | - Ying, Jiang
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China
| | - Su Lin
- The Biodesign Institute, and Department of Chemistry and Biochemistry, Arizona State University, 1001 McAllister Ave., Tempe, Arizona 85287, United States
| | - Neal W. Woodbury
- The Biodesign Institute, and Department of Chemistry and Biochemistry, Arizona State University, 1001 McAllister Ave., Tempe, Arizona 85287, United States
| |
Collapse
|
23
|
Khatypov RA, Khmelnitskiy AY, Khristin AM, Fufina TY, Vasilieva LG, Shuvalov VA. Primary charge separation within P870* in wild type and heterodimer mutants in femtosecond time domain. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2011; 1817:1392-8. [PMID: 22209778 DOI: 10.1016/j.bbabio.2011.12.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Revised: 12/09/2011] [Accepted: 12/14/2011] [Indexed: 10/14/2022]
Abstract
Primary charge separation dynamics in the reaction center (RC) of purple bacterium Rhodobacter sphaeroides and its P870 heterodimer mutants have been studied using femtosecond time-resolved spectroscopy with 20 and 40fs excitation at 870nm at 293K. Absorbance increase in the 1060-1130nm region that is presumably attributed to P(A)(δ+) cation radical molecule as a part of mixed state with a charge transfer character P*(P(A)(δ+)P(B)(δ-)) was found. This state appears at 120-180fs time delay in the wild type RC and even faster in H(L173)L and H(M202)L heterodimer mutants and precedes electron transfer (ET) to B(A) bacteriochlorophyll with absorption band at 1020nm in WT. The formation of the P(A)(δ+)B(A)(δ-) state is a result of the electron transfer from P*(P(A)(δ+)P(B)(δ-)) to the primary electron acceptor B(A) (still mixed with P*) with the apparent time delay of ~1.1ps. Next step of ET is accompanied by the 3-ps appearance of bacteriopheophytin a(-) (H(A)(-)) band at 960nm. The study of the wave packet formation upon 20-fs illumination has shown that the vibration energy of the wave packet promotes reversible overcoming of an energy barrier between two potential energy surfaces P* and P*(P(A)(δ+)B(A)(δ-)) at ~500fs. For longer excitation pulses (40fs) this promotion is absent and tunneling through an energy barrier takes about 3ps. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial.
Collapse
Affiliation(s)
- R A Khatypov
- Russian Academy of Sciences, Moscow, Russian Federation
| | | | | | | | | | | |
Collapse
|
24
|
Deshmukh SS, Williams JC, Allen JP, Kálmán L. Light-Induced Conformational Changes in Photosynthetic Reaction Centers: Redox-Regulated Proton Pathway near the Dimer. Biochemistry 2011; 50:3321-31. [DOI: 10.1021/bi200169y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sasmit S. Deshmukh
- Department of Physics, Concordia University, Montreal, Quebec H4B 1R6, Canada
| | - JoAnn C. Williams
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, United States
| | - James P. Allen
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, United States
| | - László Kálmán
- Department of Physics, Concordia University, Montreal, Quebec H4B 1R6, Canada
| |
Collapse
|
25
|
Deshmukh SS, Williams JC, Allen JP, Kálmán L. Light-Induced Conformational Changes in Photosynthetic Reaction Centers: Dielectric Relaxation in the Vicinity of the Dimer. Biochemistry 2010; 50:340-8. [DOI: 10.1021/bi101496c] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Sasmit S. Deshmukh
- Department of Physics, Concordia University, Montreal, Quebec H4B 1R6, Canada
| | - JoAnn C. Williams
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, United States
| | - James P. Allen
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, United States
| | - László Kálmán
- Department of Physics, Concordia University, Montreal, Quebec H4B 1R6, Canada
| |
Collapse
|
26
|
Pawlowicz NP, van Stokkum IHM, Breton J, van Grondelle R, Jones MR. An investigation of slow charge separation in a Tyrosine M210 to Tryptophan mutant of the Rhodobacter sphaeroides reaction center by femtosecond mid-infrared spectroscopy. Phys Chem Chem Phys 2010; 12:2693-705. [DOI: 10.1039/b905934b] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
27
|
Gibasiewicz K, Pajzderska M, Karolczak J, Dobek A. Excitation and electron transfer in reaction centers from Rhodobacter sphaeroides probed and analyzed globally in the 1-nanosecond temporal window from 330 to 700 nm. Phys Chem Chem Phys 2009; 11:10484-93. [PMID: 19890535 DOI: 10.1039/b912431d] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Global analysis of a set of room temperature transient absorption spectra of Rhodobacter sphaeroides reaction centers, recorded in wide temporal and spectral ranges and triggered by femtosecond excitation of accessory bacteriochlorophylls at 800 nm, is presented. The data give a comprehensive review of all spectral dynamics features in the visible and near UV, from 330 to 700 nm, related to the primary events in the Rb. sphaeroides reaction center: excitation energy transfer from the accessory bacteriochlorophylls (B) to the primary donor (P), primary charge separation between the primary donor and primary acceptor (bacteriopheophytin, H), and electron transfer from the primary to the secondary electron acceptor (ubiquinone). In particular, engagement of the accessory bacteriochlorophyll in primary charge separation is shown as an intermediate electron acceptor, and the initial free energy gap of approximately 40 meV, between the states P(+)B(A)(-) and P(+)H(A)(-) is estimated. The size of this gap is shown to be constant for the whole 230 ps lifetime of the P(+)H(A)(-) state. The ultrafast spectral dynamics features recorded in the visible range are presented against a background of results from similar studies performed for the last two decades.
Collapse
Affiliation(s)
- K Gibasiewicz
- Department of Physics, Adam Mickiewicz University, ul. Umultowska 85, 61-614 Poznań, Poland.
| | | | | | | |
Collapse
|
28
|
Rappaport F, Lavergne J. Thermoluminescence: theory. PHOTOSYNTHESIS RESEARCH 2009; 101:205-16. [PMID: 19533412 DOI: 10.1007/s11120-009-9437-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2008] [Accepted: 05/14/2009] [Indexed: 05/08/2023]
Abstract
Thermoluminescence (TL) probes the emission of luminescence associated with the de-trapping of a radical pair as the temperature is increased. This technique has proved useful for characterizing the energetic arrangement of cofactors in photosynthetic reaction centers. In the original TL theory, stemming from solid-state physics, the radical pair recombination was considered to coincide with the light-emitting process. In photosynthetic systems, however, recombination takes place through various routes among which the radiative pathway generally represents a relatively minor leak, and the theoretical framework must be modified accordingly. The radiative route is the one with the largest activation energy and is thus (still) more disfavored at low temperature, so that during the heating process, the TL peak tends to lag behind the decay of the radical pair. A consequence is that the integrated luminescence emission increases with the heating rate. In this article, we examine how the characteristics of the TL emission depend on the redox potentials of the cofactors, showing good agreement between theory and experimental studies on Photosystem (PS) II mutants. We also analyze the effect on (thermo-) luminescence of the connectivity of the light-harvesting pigment antenna, and show that while this should affect significantly luminescence kinetics at room temperature, the effect on TL is expected to be small.
Collapse
Affiliation(s)
- Fabrice Rappaport
- Institut de Biologie Physico-Chimique, Unité Mixte de Recherche 7141, Centre National de la Recherche Scientifique, Université Paris 6, 13 Rue Pierre et Marie Curie, Paris, France.
| | | |
Collapse
|
29
|
Szczepaniak M, Sander J, Nowaczyk M, Müller MG, Rögner M, Holzwarth AR. Charge separation, stabilization, and protein relaxation in photosystem II core particles with closed reaction center. Biophys J 2009; 96:621-31. [PMID: 19167309 DOI: 10.1016/j.bpj.2008.09.036] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2008] [Accepted: 09/22/2008] [Indexed: 10/21/2022] Open
Abstract
The fluorescence kinetics of cyanobacterial photosystem II (PSII) core particles with closed reaction centers (RCs) were studied with picosecond resolution. The data are modeled in terms of electron transfer (ET) and associated protein conformational relaxation processes, resolving four different radical pair (RP) states. The target analyses reveal the importance of protein relaxation steps in the ET chain for the functioning of PSII. We also tested previously published data on cyanobacterial PSII with open RCs using models that involved protein relaxation steps as suggested by our data on closed RCs. The rationale for this reanalysis is that at least one short-lived component could not be described in the previous simpler models. This new analysis supports the involvement of a protein relaxation step for open RCs as well. In this model the rate of ET from reduced pheophytin to the primary quinone Q(A) is determined to be 4.1 ns(-1). The rate of initial charge separation is slowed down substantially from approximately 170 ns(-1) in PSII with open RCs to 56 ns(-1) upon reduction of Q(A). However, the free-energy drop of the first RP is not changed substantially between the two RC redox states. The currently assumed mechanistic model, assuming the same early RP intermediates in both states of RC, is inconsistent with the presented energetics of the RPs. Additionally, a comparison between PSII with closed RCs in isolated cores and in intact cells reveals slightly different relaxation kinetics, with a approximately 3.7 ns component present only in isolated cores.
Collapse
Affiliation(s)
- M Szczepaniak
- Max-Planck-Institut für Bioanorganische Chemie, Ruhr, Germany
| | | | | | | | | | | |
Collapse
|
30
|
Hou HJM, Shen G, Boichenko VA, Golbeck JH, Mauzerall D. Thermodynamics of Charge Separation of Photosystem I in the menA and menB Null Mutants of Synechocystis sp. PCC 6803 Determined by Pulsed Photoacoustics. Biochemistry 2009; 48:1829-37. [DOI: 10.1021/bi801951t] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Harvey J. M. Hou
- Department of Chemistry and Biochemistry, University of Massachusetts Dartmouth, North Dartmouth, Massachusetts 02747, Department of Biochemistry and Molecular Biology and Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino 142290, Russia, and The Rockefeller University, 1230 York Avenue, New York, New York 10065
| | - Gaozhong Shen
- Department of Chemistry and Biochemistry, University of Massachusetts Dartmouth, North Dartmouth, Massachusetts 02747, Department of Biochemistry and Molecular Biology and Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino 142290, Russia, and The Rockefeller University, 1230 York Avenue, New York, New York 10065
| | - Vladimir A. Boichenko
- Department of Chemistry and Biochemistry, University of Massachusetts Dartmouth, North Dartmouth, Massachusetts 02747, Department of Biochemistry and Molecular Biology and Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino 142290, Russia, and The Rockefeller University, 1230 York Avenue, New York, New York 10065
| | - John H. Golbeck
- Department of Chemistry and Biochemistry, University of Massachusetts Dartmouth, North Dartmouth, Massachusetts 02747, Department of Biochemistry and Molecular Biology and Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino 142290, Russia, and The Rockefeller University, 1230 York Avenue, New York, New York 10065
| | - David Mauzerall
- Department of Chemistry and Biochemistry, University of Massachusetts Dartmouth, North Dartmouth, Massachusetts 02747, Department of Biochemistry and Molecular Biology and Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino 142290, Russia, and The Rockefeller University, 1230 York Avenue, New York, New York 10065
| |
Collapse
|
31
|
Mechanism of Charge Separation in Purple Bacterial Reaction Centers. THE PURPLE PHOTOTROPHIC BACTERIA 2009. [DOI: 10.1007/978-1-4020-8815-5_19] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
32
|
Chuang JI, Boxer SG, Holten D, Kirmaier C. Temperature Dependence of Electron Transfer to the M-Side Bacteriopheophytin in Rhodobacter capsulatus Reaction Centers. J Phys Chem B 2008; 112:5487-99. [DOI: 10.1021/jp800082m] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jessica I. Chuang
- Department of Chemistry, Stanford University, Stanford, California 94305-5080, and Department of Chemistry, Washington University, St. Louis, Missouri 63130-4899
| | - Steven G. Boxer
- Department of Chemistry, Stanford University, Stanford, California 94305-5080, and Department of Chemistry, Washington University, St. Louis, Missouri 63130-4899
| | - Dewey Holten
- Department of Chemistry, Stanford University, Stanford, California 94305-5080, and Department of Chemistry, Washington University, St. Louis, Missouri 63130-4899
| | - Christine Kirmaier
- Department of Chemistry, Stanford University, Stanford, California 94305-5080, and Department of Chemistry, Washington University, St. Louis, Missouri 63130-4899
| |
Collapse
|
33
|
Parkinson DY, Lee H, Fleming GR. Measuring Electronic Coupling in the Reaction Center of Purple Photosynthetic Bacteria by Two-Color, Three-Pulse Photon Echo Peak Shift Spectroscopy. J Phys Chem B 2007; 111:7449-56. [PMID: 17530796 DOI: 10.1021/jp070029q] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
One- and two-color, three-pulse photon echo peak shift spectroscopy (1C and 2C3PEPS) was used to estimate the electronic coupling between the accessory bacteriochlorophyll (B) and the bacteriopheophytin (H) in the reaction center of the purple photosynthetic bacterium Rhodobacter sphaeroides as approximately 170 +/- 30 cm-1. This is the first direct experimental determination of this parameter; it is within the range of values found in previously published calculations. The 1C3PEPS signal of the Qy band of the bacteriochlorophyll B shows that it is weakly coupled to nuclear motions of the bath, whereas the 1C3PEPS signal of the Qy band of the bacteriopheophytin, H, shows that it is more strongly coupled to the bath, but has minimal inhomogeneous broadening. Our simulations capture the major features of the data with the theoretical framework developed in our group to separately calculate the response functions and population dynamics.
Collapse
Affiliation(s)
- Dilworth Y Parkinson
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | | | | |
Collapse
|
34
|
Laible PD, Morris ZS, Thurnauer MC, Schiffer M, Hanson DK. Inter- and Intraspecific Variation in Excited-state Triplet Energy Transfer Rates in Reaction Centers of Photosynthetic Bacteria¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2003)0780114iaivie2.0.co2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
35
|
Bixon M, Jortner J. Electron Transfer-from Isolated Molecules to Biomolecules. ADVANCES IN CHEMICAL PHYSICS 2007. [DOI: 10.1002/9780470141656.ch3] [Citation(s) in RCA: 232] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
36
|
Thompson M. DNA sequence-directed assembly of two peptide bioconjugates. Bioorg Chem 2006; 34:235-47. [PMID: 16887165 DOI: 10.1016/j.bioorg.2006.06.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2006] [Revised: 06/07/2006] [Accepted: 06/14/2006] [Indexed: 11/23/2022]
Abstract
Peptide bioconjugates combine the molecular recognition features of the polypeptide from a DNA-binding protein and the DNA-sensitive fluorescence of an intercalating dye. Here, DNA template-directed assembly of two bioconjugate probes was examined by steady-state fluorescence resonance energy transfer and time-resolved single photon counting. The Förster critical distance was determined to be approximately 26 A for the oxazole yellow and thiazole orange donor-acceptor pair. The efficiency of energy transfer for two bioconjugates was a function of the number of intervening base pairs between two DNA cognate sites. These probes were sufficiently sensitive to detect sequence dependent curvature and polypeptide induced bending of the DNA. Molecular probes capable of examining spatial aspects of protein complexes at promoter sites could yield important information about the early events in transcription initiation.
Collapse
Affiliation(s)
- M Thompson
- Department of Chemistry, Michigan Technological University, Houghton, MI 49931, USA.
| |
Collapse
|
37
|
Holzwarth AR, Müller MG, Niklas J, Lubitz W. Ultrafast transient absorption studies on photosystem I reaction centers from Chlamydomonas reinhardtii. 2: mutations near the P700 reaction center chlorophylls provide new insight into the nature of the primary electron donor. Biophys J 2006; 90:552-65. [PMID: 16258055 PMCID: PMC1367060 DOI: 10.1529/biophysj.105.059824] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2005] [Accepted: 10/03/2005] [Indexed: 11/18/2022] Open
Abstract
The energy transfer and charge separation kinetics in several core Photosystem I particles of Chlamydomonas reinhardtii with point mutations around the PA and PB reaction center chlorophylls (Chls) have been studied using ultrafast transient absorption spectroscopy in the femtosecond to nanosecond time range to characterize the influence on the early electron transfer processes. The data have been analyzed in terms of kinetic compartment models. The adequate description of the transient absorption kinetics requires three different radical pairs in the time range up to approximately 100 ps. Also a charge recombination process from the first radical pair back to the excited state is present in all the mutants, as already shown previously for the wild-type (Müller, M. G., J. Niklas, W. Lubitz, and A. R. Holzwarth. 2003. Biophys. J. 85:3899-3922; and Holzwarth, A. R., M. G. Müller, J. Niklas, and W. Lubitz. 2005. J. Phys. Chem. B. 109:5903-59115). In all mutants, the primary charge separation occurs with the same effective rate constant within the error limits as in the wild-type (>>350 ns(-1)), which implies an intrinsic rate constant of charge separation of <1 ps(-1). The rate constant of the secondary electron transfer process is slowed down by a factor of approximately 2 in the mutant B-H656C, which lacks the ligand to the central metal of Chl PB. For the mutant A-T739V, which breaks the hydrogen bond to the keto carbonyl of Chl PA, only a slight slowing down of the secondary electron transfer is observed. Finally for mutant A-W679A, which has the Trp near the PA Chl replaced, either no pronounced effect or, at best, a slight increase on the secondary electron transfer rate constants is observed. The effective charge recombination rate constant is modified in all mutants to some extent, with the strongest effect observed in mutant B-H656C. Our data strongly suggest that the Chls of the PA and PB pair, constituting what is traditionally called the "primary electron donor P700", are not oxidized in the first electron transfer process, but rather only in the secondary electron transfer step. We thus propose a new electron transfer mechanism for Photosystem I where the accessory Chl(s) function as the primary electron donor(s) and the A0 Chl(s) are the primary electron acceptor(s). This new mechanism also resolves in a straightforward manner the difficulty with the previous mechanism, where an electron would have to overcome a distance of approximately 14 A in <1 ps in a single step. If interpreted within a scheme of single-sided electron transfer, our data suggest that the B-branch is the active branch, although parallel A-branch activity cannot be excluded. All the mutations do affect to a varying extent the energy difference between the reaction center excited state RC* and the first radical pair and thus affect the rate constant of charge recombination. It is interesting to note that the new mechanism proposed is in fact analogous to the electron transfer mechanism in Photosystem II, where the accessory Chl also plays the role of the primary electron donor, rather than the special Chl pair P680 (Prokhorenko, V. and A. R. Holzwarth. 2000. J. Phys. Chem. B. 104:11563-11578).
Collapse
Affiliation(s)
- Alfred R Holzwarth
- Max-Planck-Institut für Bioanorganische Chemie, D-45470 Mülheim an der Ruhr, Germany.
| | | | | | | |
Collapse
|
38
|
Litvín R, Bína D, Siffel P, Vácha F. Conformational changes and their role in non-radiative energy dissipation in photosystem II reaction centres. Photochem Photobiol Sci 2005; 4:999-1002. [PMID: 16307113 DOI: 10.1039/b506166k] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Accumulation of reduced pheophytin in photosystem II under illumination at low redox potential is known to be accompanied by a pronounced decrease of a chlorophyll fluorescence yield. Simultaneous measurement of this fluorescence quenching and absorbance changes in photosystem II reaction centres, in the presence of dithionite, showed each event to have a different temperature dependence. While fluorescence quenching was suppressed more than 20 times when measured at 77 K, pheophytin accumulation decreased only 5 times. At 77 K, the fluorescence was quenched considerably, but only in those reaction centres where reduced pheophytin had been accumulated at room temperature before sample freezing. This showed that the accumulation of reduced pheophytin above 240 K was accompanied by an additional, most probably conformational, change in the reaction centre that substantially enhanced non-radiative dissipation of excitation energy.
Collapse
Affiliation(s)
- Radek Litvín
- Department of Photosynthesis, Institute of Plant Molecular Biology, Branisovska 31, 37005 Ceske Budejovice, Czech Republic
| | | | | | | |
Collapse
|
39
|
Filus Z, Laczkó G, Wraight CA, Maróti P. Delayed fluorescence from the photosynthetic reaction center measured by electronic gating of the photomultiplier. Biopolymers 2004; 74:92-5. [PMID: 15137102 DOI: 10.1002/bip.20051] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The decay of the delayed fluorescence (920 nm) of reaction centers from the photosynthetic bacterium Rhodobacter sphaeroides R26 in the P(+)Q(A)(-) charge-separated state (P and Q(A) are the primary donor and quinone, respectively) has been monitored in a wide (100 ns to 100 ms) time range. The photomultiplier (Hamamatsu R3310-03) was protected from the intense prompt fluorescence by application of gating potential pulses (-280 V) to the first, third, and fifth dynodes during the laser pulse. The gain of the photomultiplier dropped transiently by a factor of 1 x 10(6). The delayed fluorescence showed a smooth but nonexponential decay from 100 ns to 1 ms that was explained by the relaxation of the average free energy between P* and P(+)Q(A)(-) changing from -580 to -910 meV. This relaxation is due to the slow protein response to charge separation and can be described by a Kohlrausch relaxation function with time constant of 65 micros and a stretching exponent of alpha = 0.45.
Collapse
Affiliation(s)
- Z Filus
- Department of Biophysics, University of Szeged, P.O.Box 655, Szeged, Hungary
| | | | | | | |
Collapse
|
40
|
Francia F, Palazzo G, Mallardi A, Cordone L, Venturoli G. Residual water modulates QA- -to-QB electron transfer in bacterial reaction centers embedded in trehalose amorphous matrices. Biophys J 2004; 85:2760-75. [PMID: 14507738 PMCID: PMC1303499 DOI: 10.1016/s0006-3495(03)74698-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
The role of protein dynamics in the electron transfer from the reduced primary quinone, Q(A)(-), to the secondary quinone, Q(B), was studied at room temperature in isolated reaction centers (RC) from the photosynthetic bacterium Rhodobacter sphaeroides by incorporating the protein in trehalose water systems of different trehalose/water ratios. The effects of dehydration on the reaction kinetics were examined by analyzing charge recombination after different regimes of RC photoexcitation (single laser pulse, double flash, and continuous light) as well as by monitoring flash-induced electrochromic effects in the near infrared spectral region. Independent approaches show that dehydration of RC-containing matrices causes reversible, inhomogeneous inhibition of Q(A)(-)-to-Q(B) electron transfer, involving two subpopulations of RCs. In one of these populations (i.e., active), the electron transfer to Q(B) is slowed but still successfully competing with P(+)Q(A)(-) recombination, even in the driest samples; in the other (i.e., inactive), electron transfer to Q(B) after a laser pulse is hindered, inasmuch as only recombination of the P(+)Q(A)(-) state is observed. Small residual water variations ( approximately 7 wt %) modulate fully the relative fraction of the two populations, with the active one decreasing to zero in the driest samples. Analysis of charge recombination after continuous illumination indicates that, in the inactive subpopulation, the conformational changes that rate-limit electron transfer can be slowed by >4 orders of magnitude. The reported effects are consistent with conformational gating of the reaction and demonstrate that the conformational dynamics controlling electron transfer to Q(B) is strongly enslaved to the structure and dynamics of the surrounding medium. Comparing the effects of dehydration on P(+)Q(A)(-)-->PQ(A) recombination and Q(A)(-)Q(B)-->Q(A)Q(B)(-) electron transfer suggests that conformational changes gating the latter process are distinct from those stabilizing the primary charge-separated state.
Collapse
Affiliation(s)
- Francesco Francia
- Laboratorio di Biochimica e Biofisica, Dipartimento di Biologia, Università di Bologna, Bologna, Italy
| | | | | | | | | |
Collapse
|
41
|
Chen L, Holten D, Bocian DF, Kirmaier C. Effects of Hydrogen Bonding and Structure of the Accessory Bacteriochlorophylls on Charge Separation in Rb. capsulatus Reaction Centers. J Phys Chem B 2004. [DOI: 10.1021/jp049939n] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Lei Chen
- Department of Chemistry, University of California, Riverside, California 92521-0403, and Department of Chemistry, Washington University, St. Louis, Missouri 63130-4899
| | - Dewey Holten
- Department of Chemistry, University of California, Riverside, California 92521-0403, and Department of Chemistry, Washington University, St. Louis, Missouri 63130-4899
| | - David F. Bocian
- Department of Chemistry, University of California, Riverside, California 92521-0403, and Department of Chemistry, Washington University, St. Louis, Missouri 63130-4899
| | - Christine Kirmaier
- Department of Chemistry, University of California, Riverside, California 92521-0403, and Department of Chemistry, Washington University, St. Louis, Missouri 63130-4899
| |
Collapse
|
42
|
Parson WW, Warshel A. Dependence of Photosynthetic Electron-Transfer Kinetics on Temperature and Energy in a Density-Matrix Model. J Phys Chem B 2004. [DOI: 10.1021/jp0495904] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- William W. Parson
- Department of Biochemistry, University of Washington, Box 357350, Seattle, Washington 98195-7350
| | - Arieh Warshel
- Department of Biochemistry, University of Washington, Box 357350, Seattle, Washington 98195-7350
| |
Collapse
|
43
|
Abstract
Recent applications of density functional theory to biologically relevant metal centers are reviewed. The emphasis is on reaction mechanisms, structures, and modeling. The accuracy of different functionals is discussed for standard benchmark tests of first- and second-row molecules and for transition metal systems. Modeling aspects of the protein metal complexes are discussed regarding both the size of the model being treated quantum mechanically and the treatment of the protein surrounding it. To illustrate the effects, structures computed without the effects of the protein are compared with experimental structures from enzymes, and results from simple dielectric models of the protein for electron transfer processes are described. The choice of spin state is discussed for multimetal complexes. Examples of mechanisms studied recently by density functional theory are described, such as O2 and methane activation in methane monooxygenase and O2 formation in photosystem II.
Collapse
Affiliation(s)
- P E Siegbahn
- Department of Physics, Stockholm University, Box 6730, S-113 85 Stockholm, Sweden.
| | | |
Collapse
|
44
|
Katiliene Z, Katilius E, Uyeda GH, Williams JC, Woodbury NW. Increasing the Rate of Energy Transfer between the LHI Antenna and the Reaction Center in the Photosynthetic Bacterium Rhodobacter sphaeroides. J Phys Chem B 2004. [DOI: 10.1021/jp035956l] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Zivile Katiliene
- Department of Chemistry and Biochemistry, Arizona Biodesign Institute and the Center for the Study of Early Events in Photosynthesis, Arizona State University, Tempe, Arizona 85287-1604
| | - Evaldas Katilius
- Department of Chemistry and Biochemistry, Arizona Biodesign Institute and the Center for the Study of Early Events in Photosynthesis, Arizona State University, Tempe, Arizona 85287-1604
| | - Gregory H. Uyeda
- Department of Chemistry and Biochemistry, Arizona Biodesign Institute and the Center for the Study of Early Events in Photosynthesis, Arizona State University, Tempe, Arizona 85287-1604
| | - JoAnn C. Williams
- Department of Chemistry and Biochemistry, Arizona Biodesign Institute and the Center for the Study of Early Events in Photosynthesis, Arizona State University, Tempe, Arizona 85287-1604
| | - Neal W. Woodbury
- Department of Chemistry and Biochemistry, Arizona Biodesign Institute and the Center for the Study of Early Events in Photosynthesis, Arizona State University, Tempe, Arizona 85287-1604
| |
Collapse
|
45
|
A density-matrix model of photosynthetic electron transfer with microscopically estimated vibrational relaxation times. Chem Phys 2004. [DOI: 10.1016/j.chemphys.2003.10.006] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
46
|
Semenov AY, Mamedov MD, Chamorovsky SK. Photoelectric studies of the transmembrane charge transfer reactions in photosystem I pigment-protein complexes. FEBS Lett 2003; 553:223-8. [PMID: 14572628 DOI: 10.1016/s0014-5793(03)01032-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The results of studies of charge transfer in cyanobacterial photosystem I (PS I) using the photoelectric method are reviewed. The electrogenicity in the PS I complex and its interaction with natural donors (plastocyanin, cytochrome c(6)), natural acceptors (ferredoxin, flavodoxin), or artificial acceptors and donors (methyl viologen and other redox dyes) were studied. The operating dielectric constant values in the vicinity of the charge transfer carriers in situ were calculated. The profile of distribution of the dielectric constant along the PS I pigment-protein complex (from plastocyanin or cytochrome c(6) through the chlorophyll dimer P700 to the acceptor complex) was estimated, and possible mechanisms of correlation between the local dielectric constant and electron transfer rate constant were discussed.
Collapse
Affiliation(s)
- Alexey Yu Semenov
- A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, Russia.
| | | | | |
Collapse
|
47
|
Kirmaier C, Laible PD, Hindin E, Hanson DK, Holten D. Detergent effects on primary charge separation in wild-type and mutant Rhodobacter capsulatus reaction centers. Chem Phys 2003. [DOI: 10.1016/s0301-0104(03)00283-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
48
|
Katilius E, Babendure JL, Katiliene Z, Lin S, Taguchi AKW, Woodbury NW. Manipulations of the B-Side Charge-Separated States' Energetics in the Rhodobacter sphaeroides Reaction Center. J Phys Chem B 2003. [DOI: 10.1021/jp035013o] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Evaldas Katilius
- Department of Chemistry and Biochemistry and the Center for the Study of Early Events in Photosynthesis, Arizona State University, Tempe, Arizona 85287-1604
| | - Jennie L. Babendure
- Department of Chemistry and Biochemistry and the Center for the Study of Early Events in Photosynthesis, Arizona State University, Tempe, Arizona 85287-1604
| | - Zivile Katiliene
- Department of Chemistry and Biochemistry and the Center for the Study of Early Events in Photosynthesis, Arizona State University, Tempe, Arizona 85287-1604
| | - Su Lin
- Department of Chemistry and Biochemistry and the Center for the Study of Early Events in Photosynthesis, Arizona State University, Tempe, Arizona 85287-1604
| | - Aileen K. W. Taguchi
- Department of Chemistry and Biochemistry and the Center for the Study of Early Events in Photosynthesis, Arizona State University, Tempe, Arizona 85287-1604
| | - Neal W. Woodbury
- Department of Chemistry and Biochemistry and the Center for the Study of Early Events in Photosynthesis, Arizona State University, Tempe, Arizona 85287-1604
| |
Collapse
|
49
|
Kriegl JM, Forster FK, Nienhaus GU. Charge recombination and protein dynamics in bacterial photosynthetic reaction centers entrapped in a sol-gel matrix. Biophys J 2003; 85:1851-70. [PMID: 12944298 PMCID: PMC1303357 DOI: 10.1016/s0006-3495(03)74613-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Many proteins can be immobilized in silica hydrogel matrices without compromising their function, making this a suitable technique for biosensor applications. Immobilization will in general affect protein structure and dynamics. To study these effects, we have measured the P(+)Q(A)(-) charge recombination kinetics after laser excitation of Q(B)-depleted wild-type photosynthetic reaction centers from Rhodobacter sphaeroides in a tetramethoxysilane (TMOS) sol-gel matrix and, for comparison, also in cryosolvent. The nonexponential electron transfer kinetics observed between 10 and 300 K were analyzed quantitatively using the spin boson model for the intrinsic temperature dependence of the electron transfer and an adiabatic change of the energy gap and electronic coupling caused by protein motions in response to the altered charge distributions. The analysis reveals similarities and differences in the TMOS-matrix and bulk-solvent samples. In both preparations, electron transfer is coupled to the same spectrum of low frequency phonons. As in bulk solvent, charge-solvating protein motions are present in the TMOS matrix. Large-scale conformational changes are arrested in the hydrogel, as evident from the nonexponential kinetics even at room temperature. The altered dynamics is likely responsible for the observed changes in the electronic coupling matrix element.
Collapse
Affiliation(s)
- Jan M Kriegl
- Department of Biophysics, University of Ulm, Ulm, Germany
| | | | | |
Collapse
|
50
|
Ceccarelli M, Marchi M. Simulation and Modeling of the Rhodobacter sphaeroides Bacterial Reaction Center II: Primary Charge Separation. J Phys Chem B 2003. [DOI: 10.1021/jp0303422] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Matteo Ceccarelli
- CECAM, Centre Européen de Calcul Atomique et Moleculaire, Ecole Normale Superieure de Lyon, 46 Allée d'Italie, 69364 Lyon, France
| | - Massimo Marchi
- Commissariat à l'Energie Atomique, DSV-DBJC-SBFM, Centre d'Études, Saclay, 91191 Gif-sur-Yvette Cedex, France
| |
Collapse
|