1
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Faries KM, Hanson DK, Buhrmaster JC, Hippleheuser S, Tira GA, Wyllie RM, Kohout CE, Magdaong NCM, Holten D, Laible PD, Kirmaier C. Two pathways to understanding electron transfer in reaction centers from photosynthetic bacteria: A comparison of Rhodobacter sphaeroides and Rhodobacter capsulatus mutants. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2024; 1865:149047. [PMID: 38692451 DOI: 10.1016/j.bbabio.2024.149047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 04/23/2024] [Accepted: 04/24/2024] [Indexed: 05/03/2024]
Abstract
The rates, yields, mechanisms and directionality of electron transfer (ET) are explored in twelve pairs of Rhodobacter (R.) sphaeroides and R. capsulatus mutant RCs designed to defeat ET from the excited primary donor (P*) to the A-side cofactors and re-direct ET to the normally inactive mirror-image B-side cofactors. In general, the R. sphaeroides variants have larger P+HB- yields (up to ∼90%) than their R. capsulatus analogs (up to ∼60%), where HB is the B-side bacteriopheophytin. Substitution of Tyr for Phe at L-polypeptide position L181 near BB primarily increases the contribution of fast P* → P+BB- → P+HB- two-step ET, where BB is the "bridging" B-side bacteriochlorophyll. The second step (∼6-8 ps) is slower than the first (∼3-4 ps), unlike A-side two-step ET (P* → P+BA- → P+HA-) where the second step (∼1 ps) is faster than the first (∼3-4 ps) in the native RC. Substitutions near HB, at L185 (Leu, Trp or Arg) and at M-polypeptide site M133/131 (Thr, Val or Glu), strongly affect the contribution of slower (20-50 ps) P* → P+HB- one-step superexchange ET. Both ET mechanisms are effective in directing electrons "the wrong way" to HB and both compete with internal conversion of P* to the ground state (∼200 ps) and ET to the A-side cofactors. Collectively, the work demonstrates cooperative amino-acid control of rates, yields and mechanisms of ET in bacterial RCs and how A- vs. B-side charge separation can be tuned in both species.
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Affiliation(s)
- Kaitlyn M Faries
- Department of Chemistry, Washington University, St. Louis, MO 63130, United States of America
| | - Deborah K Hanson
- Biosciences Division, Argonne National Laboratory, Lemont, IL 60439, United States of America
| | - James C Buhrmaster
- Biosciences Division, Argonne National Laboratory, Lemont, IL 60439, United States of America
| | - Stephen Hippleheuser
- Biosciences Division, Argonne National Laboratory, Lemont, IL 60439, United States of America
| | - Gregory A Tira
- Biosciences Division, Argonne National Laboratory, Lemont, IL 60439, United States of America
| | - Ryan M Wyllie
- Biosciences Division, Argonne National Laboratory, Lemont, IL 60439, United States of America
| | - Claire E Kohout
- Biosciences Division, Argonne National Laboratory, Lemont, IL 60439, United States of America
| | - Nikki Cecil M Magdaong
- Department of Chemistry, Washington University, St. Louis, MO 63130, United States of America
| | - Dewey Holten
- Department of Chemistry, Washington University, St. Louis, MO 63130, United States of America
| | - Philip D Laible
- Biosciences Division, Argonne National Laboratory, Lemont, IL 60439, United States of America
| | - Christine Kirmaier
- Department of Chemistry, Washington University, St. Louis, MO 63130, United States of America.
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2
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Yakovlev AG, Taisova AS. Downhill excitation energy flow in reaction centers of purple bacteria Rhodospirillum rubrum G9. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2024; 1865:149499. [PMID: 39069149 DOI: 10.1016/j.bbabio.2024.149499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2024] [Revised: 07/24/2024] [Accepted: 07/24/2024] [Indexed: 07/30/2024]
Abstract
Using femtosecond differential spectroscopy, excitation energy transfer in reaction centers (RCs) of the carotenoidless strain of purple bacteria Rhodospirillum rubrum G9 was studied at room temperature. Excitation and probing of the Qy, Qx and Soret absorption bands of the RCs were carried out by pulses with duration of 25-30 fs. Modeling of ΔA (light - dark) kinetics made it possible to estimate the characteristic time of various stages of excitation energy transformation. It is shown that the dynamics of the downhill energy flow in the RCs is determined both by the internal energy conversion Soret→ Qx → Qy in each cofactor and by the energy transfer H* → B* → P* (H - bacteriopheophytin, B - bacteriochlorophyll a, P - bacteriochlorophyll a dimer) between cofactors. The transfer of energy between the upper excited levels (Soret and Qx) of the cofactors accelerates its arrival to the lower exciton level of the P, from where charge separation begins. It turned out that all conversion and energy transfer processes occur within 40-160 fs: the conversion Soret → Qx occurs in 40-50 fs, the conversion Qx → Qy occurs in 100-140 fs, the transfer H* → B* has a time constant of 80-120 fs, and the transfer B* → P* has a time constant of 130-160 fs. The rate of energy transfer between the upper excited levels is close to the rate of transfer between Qy levels.
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Affiliation(s)
- Andrei G Yakovlev
- Lomonosov Moscow State University, Belozersky Institute of Physico-Chemical Biology, Leninskie Gory, 119991 Moscow, Russian Federation.
| | - Alexandra S Taisova
- Lomonosov Moscow State University, Belozersky Institute of Physico-Chemical Biology, Leninskie Gory, 119991 Moscow, Russian Federation
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3
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Xie XS. Round-Trip Journey of a Physical Chemist. J Phys Chem B 2023; 127:7800-7809. [PMID: 37731371 DOI: 10.1021/acs.jpcb.3c05597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Affiliation(s)
- Xiaoliang Sunney Xie
- Biomedical Pioneering Innovation Center, Peking University, 5 Yiheyuan Road, Beijing 100871, China
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4
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Magdaong NCM, Faries KM, Buhrmaster JC, Tira GA, Wyllie RM, Kohout CE, Hanson DK, Laible PD, Holten D, Kirmaier C. High Yield of B-Side Electron Transfer at 77 K in the Photosynthetic Reaction Center Protein from Rhodobacter sphaeroides. J Phys Chem B 2022; 126:8940-8956. [PMID: 36315401 DOI: 10.1021/acs.jpcb.2c05905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The primary electron transfer (ET) processes at 295 and 77 K are compared for the Rhodobacter sphaeroides reaction center (RC) pigment-protein complex from 13 mutants including a wild-type control. The engineered RCs bear mutations in the L and M polypeptides that largely inhibit ET from the excited state P* of the primary electron donor (P, a bacteriochlorophyll dimer) to the normally photoactive A-side cofactors and enhance ET to the C2-symmetry related, and normally photoinactive, B-side cofactors. P* decay is multiexponential at both temperatures and modeled as arising from subpopulations that differ in contributions of two-step ET (e.g., P* → P+BB- → P+HB-), one-step superexchange ET (e.g., P* → P+HB-), and P* → ground state. [HB and BB are monomeric bacteriopheophytin and bacteriochlorophyll, respectively.] The relative abundances of the subpopulations and the inherent rate constants of the P* decay routes vary with temperature. Regardless, ET to produce P+HB- is generally faster at 77 K than at 295 K by about a factor of 2. A key finding is that the yield of P+HB-, which ranges from ∼5% to ∼90% among the mutant RCs, is essentially the same at 77 K as at 295 K in each case. Overall, the results show that ET from P* to the B-side cofactors in these mutants does not require thermal activation and involves combinations of ET mechanisms analogous to those operative on the A side in the native RC.
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Affiliation(s)
- Nikki Cecil M Magdaong
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, United States
| | - Kaitlyn M Faries
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, United States
| | - James C Buhrmaster
- Biosciences Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Gregory A Tira
- Biosciences Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Ryan M Wyllie
- Biosciences Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Claire E Kohout
- Biosciences Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Deborah K Hanson
- Biosciences Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Philip D Laible
- Biosciences Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Dewey Holten
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, United States
| | - Christine Kirmaier
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, United States
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5
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Magdaong NCM, Buhrmaster JC, Faries KM, Liu H, Tira GA, Lindsey JS, Hanson DK, Holten D, Laible PD, Kirmaier C. In Situ, Protein-Mediated Generation of a Photochemically Active Chlorophyll Analogue in a Mutant Bacterial Photosynthetic Reaction Center. Biochemistry 2021; 60:1260-1275. [PMID: 33835797 DOI: 10.1021/acs.biochem.1c00137] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
All possible natural amino acids have been substituted for the native LeuL185 positioned near the B-side bacteriopheophytin (HB) in the bacterial reaction center (RC) from Rhodobacter sphaeroides. Additional mutations that enhance electron transfer to the normally inactive B-side cofactors are present. Approximately half of the isolated RCs with Glu at L185 contain a magnesium chlorin (CB) in place of HB. The chlorin is not the common BChl a oxidation product 3-desvinyl-3-acetyl chlorophyll a with a C-C bond in ring D and a C═C bond in ring B but has properties consistent with reversal of these bond orders, giving 17,18-didehydro BChl a. In such RCs, charge-separated state P+CB- forms in ∼5% yield. The other half of the GluL185-containing RCs have a bacteriochlorophyll a (BChl a) denoted βB in place of HB. Residues His, Asp, Asn, and Gln at L185 yield RCs with ≥85% βB in the HB site, while most other amino acids result in RCs that retain HB (≥95%). To the best of our knowledge, neither bacterial RCs that harbor five BChl a molecules and one chlorophyll analogue nor those with six BChl a molecules have been reported previously. The finding that altering the local environment within a cofactor binding site of a transmembrane complex leads to in situ generation of a photoactive chlorin with an unusual ring oxidation pattern suggests new strategies for amino acid control over pigment type at specific sites in photosynthetic proteins.
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Affiliation(s)
- Nikki Cecil M Magdaong
- Department of Chemistry, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - James C Buhrmaster
- Biosciences Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Kaitlyn M Faries
- Department of Chemistry, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Haijun Liu
- Department of Chemistry, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Gregory A Tira
- Biosciences Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Jonathan S Lindsey
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Deborah K Hanson
- Biosciences Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Dewey Holten
- Department of Chemistry, Washington University in St. Louis, 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 in St. Louis, St. Louis, Missouri 63130, United States
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6
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Zabelin AA, Khristin AM, Shkuropatova VA, Khatypov RA, Shkuropatov AY. Primary electron transfer in Rhodobacter sphaeroides R-26 reaction centers under dehydration conditions. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1861:148238. [PMID: 32533935 DOI: 10.1016/j.bbabio.2020.148238] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 05/28/2020] [Accepted: 06/03/2020] [Indexed: 11/26/2022]
Abstract
The photoinduced charge separation in QB-depleted reaction centers (RCs) from Rhodobacter sphaeroides R-26 in solid air-dried and vacuum-dried (~10-2 Torr) films, obtained in the presence of detergent n-dodecyl-β-D-maltoside (DM), is characterized using ultrafast transient absorption spectroscopy. It is shown that drying of RC-DM complexes is accompanied by reversible blue shifts of the ground-state absorption bands of the pigment ensemble, which suggest that no dehydration-induced structural destruction of RCs occurs in both types of films. In air-dried films, electron transfer from the excited primary electron donor P⁎ to the photoactive bacteriopheophytin HA proceeds in 4.7 ps to form the P+HA- state with essentially 100% yield. P+HA- decays in 260 ps both by electron transfer to the primary quinone QA to give the state P+QA- (87% yield) and by charge recombination to the ground state (13% yield). In vacuum-dried films, P⁎ decay is characterized by two kinetic components with time constants of 4.1 and 46 ps in a proportion of ~55%/45%, and P+HA- decays about 2-fold slower (462 ps) than in air-dried films. Deactivation of both P⁎ and P+HA- to the ground state effectively competes with the corresponding forward electron-transfer reactions in vacuum-dried RCs, reducing the yield of P+QA- to 68%. The results are compared with the data obtained for fully hydrated RCs in solution and are discussed in terms of the presence in the RC complexes of different water molecules, the removal/displacement of which affects spectral properties of pigment cofactors and rates and yields of the electron-transfer reactions.
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Affiliation(s)
- Alexey A Zabelin
- Institute of Basic Biological Problems of the Russian Academy of Sciences, Federal Research Center "Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences", 142290 Pushchino, Moscow Region, Russian Federation
| | - Anton M Khristin
- Institute of Basic Biological Problems of the Russian Academy of Sciences, Federal Research Center "Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences", 142290 Pushchino, Moscow Region, Russian Federation
| | - Valentina A Shkuropatova
- Institute of Basic Biological Problems of the Russian Academy of Sciences, Federal Research Center "Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences", 142290 Pushchino, Moscow Region, Russian Federation
| | - Ravil A Khatypov
- Institute of Basic Biological Problems of the Russian Academy of Sciences, Federal Research Center "Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences", 142290 Pushchino, Moscow Region, Russian Federation
| | - Anatoly Ya Shkuropatov
- Institute of Basic Biological Problems of the Russian Academy of Sciences, Federal Research Center "Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences", 142290 Pushchino, Moscow Region, Russian Federation.
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7
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Switching sides-Reengineered primary charge separation in the bacterial photosynthetic reaction center. Proc Natl Acad Sci U S A 2019; 117:865-871. [PMID: 31892543 DOI: 10.1073/pnas.1916119117] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We report 90% yield of electron transfer (ET) from the singlet excited state P* of the primary electron-donor P (a bacteriochlorophyll dimer) to the B-side bacteriopheophytin (HB) in the bacterial photosynthetic reaction center (RC). Starting from a platform Rhodobacter sphaeroides RC bearing several amino acid changes, an Arg in place of the native Leu at L185-positioned over one face of HB and only ∼4 Å from the 4 central nitrogens of the HB macrocycle-is the key additional mutation providing 90% yield of P+HB - This all but matches the near-unity yield of A-side P+HA - charge separation in the native RC. The 90% yield of ET to HB derives from (minimally) 3 P* populations with distinct means of P* decay. In an ∼40% population, P* decays in ∼4 ps via a 2-step process involving a short-lived P+BB - intermediate, analogous to initial charge separation on the A side of wild-type RCs. In an ∼50% population, P* → P+HB - conversion takes place in ∼20 ps by a superexchange mechanism mediated by BB An ∼10% population of P* decays in ∼150 ps largely by internal conversion. These results address the long-standing dichotomy of A- versus B-side initial charge separation in native RCs and have implications for the mechanism(s) and timescale of initial ET that are required to achieve a near-quantitative yield of unidirectional charge separation.
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8
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Faries KM, Kohout CE, Wang GX, Hanson DK, Holten D, Laible PD, Kirmaier C. Consequences of saturation mutagenesis of the protein ligand to the B-side monomeric bacteriochlorophyll in reaction centers from Rhodobacter capsulatus. PHOTOSYNTHESIS RESEARCH 2019; 141:273-290. [PMID: 30859455 DOI: 10.1007/s11120-019-00626-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Accepted: 02/07/2019] [Indexed: 06/09/2023]
Abstract
In bacterial reaction centers (RCs), photon-induced initial charge separation uses an A-side bacteriochlorophyll (BChl, BA) and bacteriopheophytin (BPh, HA), while the near-mirror image B-side BB and HB cofactors are inactive. Two new sets of Rhodobacter capsulatus RC mutants were designed, both bearing substitution of all amino acids for the native histidine M180 (M-polypeptide residue 180) ligand to the core Mg ion of BB. Residues are identified that largely result in retention of a BChl in the BB site (Asp, Ser, Pro, Gln, Asn, Gly, Cys, Lys, and Thr), ones that largely harbor the Mg-free BPh in the BB site (Leu and Ile), and ones for which isolated RCs are comprised of a substantial mixture of these two RC types (Ala, Glu, Val, Met and, in one set, Arg). No protein was isolated when M180 is Trp, Tyr, Phe, or (in one set) Arg. These findings are corroborated by ground state spectra, pigment extractions, ultrafast transient absorption studies, and the yields of B-side transmembrane charge separation. The changes in coordination chemistries did not reveal an RC with sufficiently precise poising of the redox properties of the BB-site cofactor to result in a high yield of B-side electron transfer to HB. Insights are gleaned into the amino acid properties that support BChl in the BB site and into the widely observed multi-exponential decay of the excited state of the primary electron donor. The results also have direct implications for tuning free energies of the charge-separated intermediates in RCs and mimetic systems.
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Affiliation(s)
- Kaitlyn M Faries
- Department of Chemistry, Washington University, St. Louis, MO, 63130, USA
| | - Claire E Kohout
- Biosciences Division, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Grace Xiyu Wang
- Biosciences Division, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Deborah K Hanson
- Biosciences Division, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Dewey Holten
- Department of Chemistry, Washington University, St. Louis, MO, 63130, USA
| | - Philip D Laible
- Biosciences Division, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Christine Kirmaier
- Department of Chemistry, Washington University, St. Louis, MO, 63130, USA.
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9
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Saggu M, Carter B, Zhou X, Faries K, Cegelski L, Holten D, Boxer SG, Kirmaier C. Putative hydrogen bond to tyrosine M208 in photosynthetic reaction centers from Rhodobacter capsulatus significantly slows primary charge separation. J Phys Chem B 2014; 118:6721-32. [PMID: 24902471 PMCID: PMC4064694 DOI: 10.1021/jp503422c] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
![]()
Slow, ∼50
ps, P* → P+HA– electron
transfer is observed in Rhodobacter
capsulatus reaction centers (RCs) bearing the native
Tyr residue at M208 and the single amino acid change of isoleucine
at M204 to glutamic acid. The P* decay kinetics are unusually homogeneous
(single exponential) at room temperature. Comparative solid-state
NMR of [4′-13C]Tyr labeled wild-type and M204E RCs
show that the chemical shift of Tyr M208 is significantly altered
in the M204E mutant and in a manner consistent with formation of a
hydrogen bond to the Tyr M208 hydroxyl group. Models based on RC crystal
structure coordinates indicate that if such a hydrogen bond is formed
between the Glu at M204 and the M208 Tyr hydroxyl group, the −OH
would be oriented in a fashion expected (based on the calculations
by Alden et al., J. Phys. Chem.1996, 100, 16761–16770) to destabilize P+BA– in free energy. Alteration
of the environment of Tyr M208 and BA by Glu M204 via this
putative hydrogen bond has a powerful influence on primary charge
separation.
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Affiliation(s)
- Miguel Saggu
- Department of Chemistry, Stanford University , Stanford, California 94305-5012, United States
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10
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Kosumi D, Nakagawa K, Sakai S, Nagaoka Y, Maruta S, Sugisaki M, Dewa T, Nango M, Hashimoto H. Ultrafast intramolecular relaxation dynamics of Mg- and Zn-bacteriochlorophyll a. J Chem Phys 2014; 139:034311. [PMID: 23883031 DOI: 10.1063/1.4813526] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Ultrafast excited-state dynamics of the photosynthetic pigment (Mg-)bacteriochlorophyll a and its Zn-substituted form were investigated by steady-state absorption∕fluorescence and femtosecond pump-probe spectroscopic measurements. The obtained steady-state absorption and fluorescence spectra of bacteriochlorophyll a in solution showed that the central metal compound significantly affects the energy of the Qx state, but has almost no effect on the Qy state. Photo-induced absorption spectra were recorded upon excitation of Mg- and Zn-bacteriochlorophyll a into either their Qx or Qy state. By comparing the kinetic traces of transient absorption, ground-state beaching, and stimulated emission after excitation to the Qx or Qy state, we showed that the Qx state was substantially incorporated in the ultrafast excited-state dynamics of bacteriochlorophyll a. Based on these observations, the lifetime of the Qx state was determined to be 50 and 70 fs for Mg- and Zn-bacteriochlorophyll a, respectively, indicating that the lifetime was influenced by the central metal atom due to the change of the energy gap between the Qx and Qy states.
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Affiliation(s)
- Daisuke Kosumi
- The Osaka City University Advanced Research Institute for Natural Science and Technology, 3-3-138 Sugimoto, Osaka 558-8585, Japan.
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11
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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]
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12
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Chin CH, Shiu HJ, Wang HW, Chen YL, Wang CC, Lin SH, Hayashi M. Theoretical Treatments of Radiationless Transitions. J CHIN CHEM SOC-TAIP 2013. [DOI: 10.1002/jccs.200600016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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13
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Models of Ultrafast Energy and Electron Transfers in Bacterial Reaction Centers. J CHIN CHEM SOC-TAIP 2013. [DOI: 10.1002/jccs.200000101] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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14
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Chang CH, Hayashi M, Chang R, Liang KK, Yang TS, Lin SH. A Theoretical Analysis of Absorption Spectra and Dynamics of Photosynthetic Reaction Centers. J CHIN CHEM SOC-TAIP 2013. [DOI: 10.1002/jccs.200000107] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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15
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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.
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Affiliation(s)
- Zhi Guo
- The Biodesign Institute at Arizona State University, Tempe, Arizona, USA
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16
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Khmelnitskiy AY, Khatypov RA, Khristin AM, Leonova MM, Vasilieva LG, Shuvalov VA. Charge separation in Rhodobacter sphaeroides mutant reaction centers with increased midpoint potential of the primary electron donor. BIOCHEMISTRY (MOSCOW) 2013; 78:60-7. [DOI: 10.1134/s0006297913010070] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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17
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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
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Abstract
Photosynthetic reaction centers (PRCs) employ multiple-step tunneling (hopping) to separate electrons and holes that ultimately drive the chemistry required for metabolism. We recently developed hopping maps that can be used to interpret the rates and energetics of electron/hole hopping in three-site (donor-intermediate-acceptor) tunneling reactions, including those in PRCs. Here we analyze several key ET reactions in PRCs, including forward ET in the L-branch, and hopping that could involve thermodynamically uphill intermediates in the M-branch, which is ET-inactive in vivo. We also explore charge recombination reactions, which could involve hopping. Our hopping maps support the view that electron flow in PRCs involves strong electronic coupling between cofactors and reorganization energies that are among the lowest in biology (≤ 0.4 eV).
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Paschenko VZ, Gorokhov VV, Korvatovskiy BN, Bocharov EA, Knox PP, Sarkisov OM, Theiss C, Eichler HJ, Renger G, Rubin AB. The rate of Q(x)→Q(y) relaxation in bacteriochlorophylls of reaction centers from Rhodobacter sphaeroides determined by kinetics of the ultrafast carotenoid bandshift. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1817:1399-406. [PMID: 22366029 DOI: 10.1016/j.bbabio.2012.02.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Revised: 01/23/2012] [Accepted: 02/07/2012] [Indexed: 10/14/2022]
Abstract
Transient absorption changes induced by excitation of isolated reaction centers (RCs) from Rhodobacter sphaeroides with 600nm laser pulses of 20fs (full width at half maximum) were monitored in the wavelength region of 420-560nm. The spectral features of the spectrum obtained are characteristic for an electrochromic band shift of the single carotenoid (Car) molecule spheroidene, which is an integral constituent of these RCs. This effect is assigned to an electrochromic bandshift of Car due to the local electric field of the dipole moment formed by electronic excitation of bacteriochlorophyll (BChl) molecule(s) in the neighborhood of Car. Based on the known distances between the pigments, the monomeric BChl (B(B)) in the inactive B-branch is inferred to dominate this effect. The excitation of B(B) at 600nm leads to a transition into the S(2) state (Q(x) band), which is followed by rapid internal conversion to the S(1) state (Q(y) band), thus leading to a change of strength and orientation of the dipole moment, i.e., of the electric field acting on the Car molecule. Therefore, the time course of the electrochromic bandshift reflects the rate of the internal conversion from S(2) to S(1) of B(B). The evaluation of the kinetics leads to a value of 30fs for this relaxation process. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial.
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Affiliation(s)
- Vladimir Z Paschenko
- Department of Biophysics, Biology Faculty of the M.V. Lomonosov Moscow State University, Moscow, Russia.
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Leonova MM, Fufina TY, Vasilieva LG, Shuvalov VA. Structure-function investigations of bacterial photosynthetic reaction centers. BIOCHEMISTRY (MOSCOW) 2012; 76:1465-83. [DOI: 10.1134/s0006297911130074] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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21
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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
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22
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Guo Z, Lin S, Xin Y, Wang H, Blankenship RE, Woodbury NW. Comparing the temperature dependence of photosynthetic electron transfer in Chloroflexus aurantiacus and Rhodobactor sphaeroides reaction centers. J Phys Chem B 2011; 115:11230-8. [PMID: 21827152 DOI: 10.1021/jp204239v] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The process of electron transfer from the special pair, P, to the primary electron donor, H(A), in quinone-depleted reaction centers (RCs) of Chloroflexus (Cf.) aurantiacus has been investigated over the temperature range from 10 to 295 K using time-resolved pump-probe spectroscopic techniques. The kinetics of the electron transfer reaction, P* → P(+)H(A)(-), was found to be nonexponential, and the degree of nonexponentiality increased strongly as temperature decreased. The temperature-dependent behavior of electron transfer in Cf. aurantiacus RCs was compared with that of the purple bacterium Rhodobacter (Rb.) sphaeroides . Distinct transitions were found in the temperature-dependent kinetics of both Cf. aurantiacus and Rb. sphaeroides RCs, at around 220 and 160 K, respectively. Structural differences between these two RCs, which may be associated with those differences, are discussed. It is suggested that weaker protein-cofactor hydrogen bonding, stronger electrostatic interactions at the protein surface, and larger solvent interactions likely contribute to the higher transition temperature in Cf. aurantiacus RCs temperature-dependent kinetics compared with that of Rb. sphaeroides RCs. The reaction-diffusion model provides an accurate description for the room-temperature electron transfer kinetics in Cf. aurantiacus RCs with no free parameters, using coupling and reorganization energy values previously determined for Rb. sphaeroides , along with an experimental measure of protein conformational diffusion dynamics and an experimental literature value of the free energy gap between P* and P(+)H(A)(-).
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Affiliation(s)
- Zhi Guo
- The Biodesign Institute at Arizona State University, Arizona State University, Tempe, Arizona 85287-5201, USA
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23
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Nabiev I, Rakovich A, Sukhanova A, Lukashev E, Zagidullin V, Pachenko V, Rakovich YP, Donegan JF, Rubin AB, Govorov AO. Fluorescent Quantum Dots as Artificial Antennas for Enhanced Light Harvesting and Energy Transfer to Photosynthetic Reaction Centers. Angew Chem Int Ed Engl 2010. [DOI: 10.1002/ange.201003067] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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24
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Nabiev I, Rakovich A, Sukhanova A, Lukashev E, Zagidullin V, Pachenko V, Rakovich YP, Donegan JF, Rubin AB, Govorov AO. Fluorescent Quantum Dots as Artificial Antennas for Enhanced Light Harvesting and Energy Transfer to Photosynthetic Reaction Centers. Angew Chem Int Ed Engl 2010; 49:7217-21. [DOI: 10.1002/anie.201003067] [Citation(s) in RCA: 145] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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25
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Abstract
Although the three-dimensional structure of the bacterial photosynthetic reaction center (RC) reveals a high level of structural symmetry, with two nearly equivalent potential electron transfer pathways, the RC is functionally asymmetric: Electron transfer occurs along only one of the two possible pathways. In order to determine the origins of this symmetry breaking, the internal electric field present in the RC when charge is separated onto structurally characterized sites was probed by using absorption band shifts of the chromophores within the RC. The sensitivity of each probe chromophore to an electric field was calibrated by measuring the Stark effect spectrum, the change in absorption due to an externally applied electric field. A quantitative comparison of the observed absorption band shifts and those predicted from vacuum electrostatics gives information on the effective dielectric constant of the protein complex. These results reveal a significant asymmetry in the effective dielectric strength of the protein complex along the two potential electron transfer pathways, with a substantially higher dielectric strength along the functional pathway. This dielectric asymmetry could be a dominant factor in determining the functional asymmetry of electron transfer in the RC.
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26
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Müller P, Bieser G, Hartwich G, Langenbacher T, Lossau H, Ogrodnik A, Michel-Beyerle ME. The internal conversion rate of the primary donor in reaction centers of Rhodobacter sphaeroides. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/bbpc.19961001207] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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27
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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.
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Affiliation(s)
- K Gibasiewicz
- Department of Physics, Adam Mickiewicz University, ul. Umultowska 85, 61-614 Poznań, Poland.
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28
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Gibasiewicz K, Pajzderska M, Ziółek M, Karolczak J, Dobek A. Internal Electrostatic Control of the Primary Charge Separation and Recombination in Reaction Centers from Rhodobacter sphaeroides Revealed by Femtosecond Transient Absorption. J Phys Chem B 2009; 113:11023-31. [DOI: 10.1021/jp811234q] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- K. Gibasiewicz
- Department of Physics, Adam Mickiewicz University, ul. Umultowska 85, 61-614 Poznań, Poland
| | - M. Pajzderska
- Department of Physics, Adam Mickiewicz University, ul. Umultowska 85, 61-614 Poznań, Poland
| | - M. Ziółek
- Department of Physics, Adam Mickiewicz University, ul. Umultowska 85, 61-614 Poznań, Poland
| | - J. Karolczak
- Department of Physics, Adam Mickiewicz University, ul. Umultowska 85, 61-614 Poznań, Poland
| | - A. Dobek
- Department of Physics, Adam Mickiewicz University, ul. Umultowska 85, 61-614 Poznań, Poland
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29
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Multipulse spectroscopy on the wild-type and YM210W Bacterial Reaction Centre uncovers a new intermediate state in the special pair excited state. Chem Phys Lett 2009. [DOI: 10.1016/j.cplett.2009.04.081] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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30
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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]
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31
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Wang H, Lin S, Woodbury NW. Excitation wavelength dependence of primary charge separation in reaction centers from Rhodobacter sphaeroides. J Phys Chem B 2008; 112:14296-301. [PMID: 18939793 DOI: 10.1021/jp8058799] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The excitation wavelength dependence of the initial electron transfer rate in both wild type and mutant reaction centers from Rhodobacter sphaeroides has been studied between 840 and 920 nm as a function of temperature (10-295 K). The dynamics of primary charge separation show no resolvable excitation wavelength dependence at room temperature over this spectral range. A small variation in rate with excitation wavelength is observed at cryogenic temperatures. The low temperature results cannot be explained in terms either of a nonequilibrium model that assumes that the primary charge separation starts from a vibrationally hot state or a model that assumes a static inhomogeneous distribution of electron transfer driving forces. Instead these results are consistent with the concept that primary charge separation kinetics are controlled by the dynamics of protein conformational diffusion.
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Affiliation(s)
- Haiyu Wang
- Biodesign Institute at Arizona State University and Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-5201, USA
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32
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Huang L, Wiederrecht GP, Utschig LM, Schlesselman SL, Xydis C, Laible PD, Hanson DK, Tiede DM. Correlating Ultrafast Function with Structure in Single Crystals of the Photosynthetic Reaction Center. Biochemistry 2008; 47:11387-9. [DOI: 10.1021/bi801026g] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Libai Huang
- Chemical Sciences and Engineering Division, Center for Nanoscale Materials, and Biosciences Division, Argonne National Laboratory, Argonne, Illinois 60439-4831
| | - Gary P. Wiederrecht
- Chemical Sciences and Engineering Division, Center for Nanoscale Materials, and Biosciences Division, Argonne National Laboratory, Argonne, Illinois 60439-4831
| | - Lisa M. Utschig
- Chemical Sciences and Engineering Division, Center for Nanoscale Materials, and Biosciences Division, Argonne National Laboratory, Argonne, Illinois 60439-4831
| | - Sandra L. Schlesselman
- Chemical Sciences and Engineering Division, Center for Nanoscale Materials, and Biosciences Division, Argonne National Laboratory, Argonne, Illinois 60439-4831
| | - Christina Xydis
- Chemical Sciences and Engineering Division, Center for Nanoscale Materials, and Biosciences Division, Argonne National Laboratory, Argonne, Illinois 60439-4831
| | - Philip D. Laible
- Chemical Sciences and Engineering Division, Center for Nanoscale Materials, and Biosciences Division, Argonne National Laboratory, Argonne, Illinois 60439-4831
| | - Deborah K. Hanson
- Chemical Sciences and Engineering Division, Center for Nanoscale Materials, and Biosciences Division, Argonne National Laboratory, Argonne, Illinois 60439-4831
| | - David M. Tiede
- Chemical Sciences and Engineering Division, Center for Nanoscale Materials, and Biosciences Division, Argonne National Laboratory, Argonne, Illinois 60439-4831
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33
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LeBard DN, Kapko V, Matyushov DV. Energetics and kinetics of primary charge separation in bacterial photosynthesis. J Phys Chem B 2008; 112:10322-42. [PMID: 18636767 DOI: 10.1021/jp8016503] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We report the results of molecular dynamics (MD) simulations and formal modeling of the free-energy surfaces and reaction rates of primary charge separation in the reaction center of Rhodobacter sphaeroides. Two simulation protocols were used to produce MD trajectories. Standard force-field potentials were employed in the first protocol. In the second protocol, the special pair was made polarizable to reproduce a high polarizability of its photoexcited state observed by Stark spectroscopy. The charge distribution between covalent and charge-transfer states of the special pair was dynamically adjusted during the simulation run. We found from both protocols that the breadth of electrostatic fluctuations of the protein/water environment far exceeds previous estimates, resulting in about 1.6 eV reorganization energy of electron transfer in the first protocol and 2.5 eV in the second protocol. Most of these electrostatic fluctuations become dynamically frozen on the time scale of primary charge separation, resulting in much smaller solvation contributions to the activation barrier. While water dominates solvation thermodynamics on long observation times, protein emerges as the major thermal bath coupled to electron transfer on the picosecond time of the reaction. Marcus parabolas were obtained for the free-energy surfaces of electron transfer by using the first protocol, while a highly asymmetric surface was obtained in the second protocol. A nonergodic formulation of the diffusion-reaction electron-transfer kinetics has allowed us to reproduce the experimental results for both the temperature dependence of the rate and the nonexponential decay of the population of the photoexcited special pair.
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Affiliation(s)
- David N LeBard
- Center for Biological Physics, Arizona State University, Tempe, AZ 85287-1604, USA
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34
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Leupold D. PHOTOBIOLOGICAL APPLICATION OF NONLINEAR VISIBLE/NIR-SPECTROSCOPIC TECHNIQUES, EXEMPLIFIED BY THE PRIMARY PROCESSES OF BACTERIAL PHOTOSYNTHESIS. Photochem Photobiol 2008. [DOI: 10.1111/j.1751-1097.1995.tb02398.x] [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]
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35
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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.
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Affiliation(s)
- Dilworth Y Parkinson
- Department of Chemistry, University of California, Berkeley, California 94720, USA
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36
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Wang H, Lin S, Allen JP, Williams JC, Blankert S, Laser C, Woodbury NW. Protein Dynamics Control the Kinetics of Initial Electron Transfer in Photosynthesis. Science 2007; 316:747-50. [PMID: 17478721 DOI: 10.1126/science.1140030] [Citation(s) in RCA: 183] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The initial electron transfer dynamics during photosynthesis have been studied in Rhodobacter sphaeroides reaction centers from wild type and 14 mutants in which the driving force and the kinetics of charge separation vary over a broad range. Surprisingly, the protein relaxation kinetics, as measured by tryptophan absorbance changes, are invariant in these mutants. By applying a reaction-diffusion model, we can fit the complex electron transfer kinetics of each mutant quantitatively, varying only the driving force. These results indicate that initial photosynthetic charge separation is limited by protein dynamics rather than by a static electron transfer barrier.
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Affiliation(s)
- Haiyu Wang
- Biodesign Institute, Arizona State University, 1001 South McAllister Avenue, Tempe, AZ 85287-5201, USA
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37
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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]
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38
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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]
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39
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Domcke W, Stock G. Theory of Ultrafast Nonadiabatic Excited-State Processes and their Spectroscopic Detection in Real Time. ADVANCES IN CHEMICAL PHYSICS 2007. [DOI: 10.1002/9780470141595.ch1] [Citation(s) in RCA: 250] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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40
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Tomi T, Shibata Y, Ikeda Y, Taniguchi S, Haik C, Mataga N, Shimada K, Itoh S. Energy and electron transfer in the photosynthetic reaction center complex of Acidiphilium rubrum containing Zn-bacteriochlorophyll a studied by femtosecond up-conversion spectroscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2007; 1767:22-30. [PMID: 17169326 DOI: 10.1016/j.bbabio.2006.10.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2006] [Revised: 10/11/2006] [Accepted: 10/27/2006] [Indexed: 11/21/2022]
Abstract
A photosynthetic reaction center (RC) complex was isolated from a purple bacterium, Acidiphilium rubrum. The RC contains bacteriochlorophyll a containing Zn as a central metal (Zn-BChl a) and bacteriopheophytin a (BPhe a) but no Mg-BChl a. The absorption peaks of the Zn-BChl a dimer (P(Zn)), the accessory Zn-BChl a (B(Zn)), and BPhe a (H) at 4 K in the RC showed peaks at 875, 792, and 753 nm, respectively. These peaks were shorter than the corresponding peaks in Rhodobacter sphaeroides RC that has Mg-BChl a. The kinetics of fluorescence from P(Zn)(*), measured by fluorescence up-conversion, showed the rise and the major decay with time constants of 0.16 and 3.3 ps, respectively. The former represents the energy transfer from B(Zn)(*) to P(Zn), and the latter, the electron transfer from P(Zn) to H. The angle between the transition dipoles of B(Zn) and P(Zn) was estimated to be 36 degrees based on the fluorescence anisotropy. The time constants and the angle are almost equal to those in the Rb. sphaeroides RC. The high efficiency of A. rubrum RC seems to be enabled by the chemical property of Zn-BChl a and by the L168HE modification of the RC protein that modifies P(Zn).
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Affiliation(s)
- Tetsuo Tomi
- Department of Material Science (Physics), Graduate School of Science, Nagoya University, Furocho, Chikusa, Nagoya 464-8602, Japan
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41
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Gorokhov VV, Pashchenko VZ, Sarkisov OM, Rubin AB. Spectral and temporal dynamics of transitional processes in the reaction centers of Rhodobacter sphaeroides in the region of 780–830 nm. DOKL BIOCHEM BIOPHYS 2006; 406:40-3. [PMID: 16584005 DOI: 10.1134/s160767290601011x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- V V Gorokhov
- Biological Faculty, Moscow State University, Vorob'evy gory, Moscow 119899 Russia
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42
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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]
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43
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Pisliakov AV, Gelin MF, Domcke W. Detection of Electronic and Vibrational Coherence Effects in Electron-Transfer Systems by Femtosecond Time-Resolved Fluorescence Spectroscopy: Theoretical Aspects. J Phys Chem A 2003. [DOI: 10.1021/jp027491p] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- A. V. Pisliakov
- Institute of Physical and Theoretical Chemistry, Technical University of Munich, Lichtenbergstrasse 4, 85747 Garching, Germany, and Institute of Molecular and Atomic Physics, National Academy of Sciences of Belarus, Skaryna Avenue 70, Minsk 220072, Belarus
| | - M. F. Gelin
- Institute of Physical and Theoretical Chemistry, Technical University of Munich, Lichtenbergstrasse 4, 85747 Garching, Germany, and Institute of Molecular and Atomic Physics, National Academy of Sciences of Belarus, Skaryna Avenue 70, Minsk 220072, Belarus
| | - W. Domcke
- Institute of Physical and Theoretical Chemistry, Technical University of Munich, Lichtenbergstrasse 4, 85747 Garching, Germany, and Institute of Molecular and Atomic Physics, National Academy of Sciences of Belarus, Skaryna Avenue 70, Minsk 220072, Belarus
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44
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Barter LMC, Durrant JR, Klug DR. A quantitative structure-function relationship for the Photosystem II reaction center: supermolecular behavior in natural photosynthesis. Proc Natl Acad Sci U S A 2003; 100:946-51. [PMID: 12538865 PMCID: PMC298706 DOI: 10.1073/pnas.0136891100] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Light-induced charge separation is the primary photochemical event of photosynthesis. Efficient charge separation in photosynthetic reaction centers requires the balancing of electron and excitation energy transfer processes, and in Photosystem II (PSII), these processes are particularly closely entangled. Calculations that treat the cofactors of the PSII reaction center as a supermolecular complex allow energy and electron transfer reactions to be described in a unified way. This calculational approach is shown to be in good agreement with experimentally observed energy and electron transfer dynamics. This supermolecular view also correctly predicts the effect of changing the redox potentials of cofactors by site-directed mutagenesis, thus providing a unified and quantitative structure-function relationship for the PSII reaction center.
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Affiliation(s)
- Laura M C Barter
- Department of Chemistry, Imperial College, London SW7 2AY, United Kingdom
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Ceccarelli M, Marchi M. Simulation and Modeling of the Rhodobacter sphaeroides Bacterial Reaction Center: Structure and Interactions. J Phys Chem B 2003. [DOI: 10.1021/jp0270001] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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
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Huppman P, Arlt T, Penzkofer H, Schmidt S, Bibikova M, Dohse B, Oesterhelt D, Wachtveit J, Zinth W. Kinetics, energetics, and electronic coupling of the primary electron transfer reactions in mutated reaction centers of Blastochloris viridis. Biophys J 2002; 82:3186-97. [PMID: 12023243 PMCID: PMC1302108 DOI: 10.1016/s0006-3495(02)75661-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Femtosecond spectroscopy in combination with site-directed mutagenesis has been used to study the dynamics of primary electron transfer in native and 12 mutated reaction centers of Blastochloris (B) (formerly called Rhodopseudomonas) viridis. The decay times of the first excited state P* vary at room temperature between of 0.6 and 50 ps, and at low temperatures between 0.25 and 90 ps. These changes in time constants are discussed within the scope of nonadiabatic electron transfer theory using different models: 1) If the mutation is assumed to predominantly influence the energetics of the primary electron transfer intermediates, the analysis of the room temperature data for the first electron transfer step to the intermediate P(+)B(A)(-) yields a reorganization energy lambda = 600 +/- 200 cm(-1) and a free energy gap Delta G ranging from -600 cm(-1) to 800 cm(-1). However, this analysis fails to describe the temperature dependence of the reaction rates. 2) A more realistic description of the temperature dependence of the primary electron transfer requires different values for the energetics and specific variations of the electronic coupling upon mutation. Apparently the mutations also lead to pronounced changes in the electronic coupling, which may even dominate the change in the reaction rate. One main message of the paper is that a simple relationship between mutation and a change in one reaction parameter cannot be given and that at the very least the electronic coupling is changed upon mutation.
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Affiliation(s)
- P Huppman
- Institut für BioMolekulare Optik, Sektion Physik, Ludwig-Maximilians-Universität, D-80538 München, Germany
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Schenkl S, Spörlein S, Müh F, Witt H, Lubitz W, Zinth W, Wachtveitl J. Selective perturbation of the second electron transfer step in mutant bacterial reaction centers. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1554:36-47. [PMID: 12034469 DOI: 10.1016/s0005-2728(02)00211-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
In order to specifically perturb the primary electron acceptor B(A) -- a monomeric bacteriochlorophyll (BChl) a -- involved in bacterial photosynthetic charge separation (CS), the protein environment of B(A) in the reaction center (RC) of Rhodobacter sphaeroides was modified by site-directed mutagenesis. Isolated RCs were characterized by redox titrations, low temperature optical spectroscopy, ENDOR/TRIPLE resonance spectroscopy and femtosecond time-resolved spectroscopy. Two mutations were studied: In the GS(M203) mutant a serine is introduced near the ring E keto group of B(A), while in FY(L146) a phenylalanine near the ring A acetyl group of B(A) is replaced by tyrosine. In all mutations the oxidation potential of the primary electron donor P as well as the electronic structure of both the P(*+) radical cation and the radical anion of the secondary electron acceptor, H(A)(*-), are not significantly altered compared to the wild type (WT), while changes of the optical absorption spectra at 77 K in the BChl Q(X) and Q(Y) regions are observed. The GS(M203) mutation only leads to a minor retardation of the CS reactions at room temperature, whereas for FY(L146) significant deviations from the native electron transfer (ET) rates could be detected: In addition to a faster first (2.9 ps) and a slower second (1 ps) ET step, a new 8-ps time constant was found in the FY(L146) mutant, which can be ascribed to a fraction of RCs with slowed down secondary ET. The results allow us to address the functional role of the acetyl group of B(A) and question the role of the free energy changes as the main determining factor of ET rates in RCs. It is concluded that structural rearrangements alter the electronic coupling between the pigments and thereby influence the rate of fast CS.
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Affiliation(s)
- Selma Schenkl
- Sektion Physik, Ludwig-Maximilians-Universität München, Oettingenstr. 67, 80538 Munich, Germany
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Abstract
The bacterial reaction centre is undoubtedly one of the most heavily studied electron transfer proteins and, as this article has tried to describe, it has made some unique contributions to our understanding of biological electron transfer and coupled protonation reactions, and has provided fascinating information in areas that concern basic properties such as protein heterogeneity and protein dynamics. Despite intensive study, much remains to be learned about how this protein catalyses the conversion of solar energy into a form that can be used by the cell. In particular, the dynamic roles played by the protein are still poorly understood. The wide range of time-scales over which the reaction centre catalyses electron transfer, and the relative ease with which electron transfer can be triggered and monitored, will ensure that the reaction centre will continue to be used as a laboratory for testing ideas about the nature of biological electron transfer for many years to come.
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Affiliation(s)
- M E van Brederode
- Faculty of Sciences, Division of Physics and Astronomy, Department of Biophysics and Physics of Complex Systems, Free University of Amsterdam, de Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
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Chang CH, Hayashi M, Liang KK, Chang R, Lin SH. A Theoretical Analysis of Absorption Spectra of Photosynthetic Reaction Centers: Mechanism of Temperature Dependent Peak Shift. J Phys Chem B 2001. [DOI: 10.1021/jp0020438] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- C. H. Chang
- Department of Chemistry, National Taiwan University, Taipei 106, Taiwan R.O.C., Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei 106, Taiwan R.O.C., and Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604
| | - M. Hayashi
- Department of Chemistry, National Taiwan University, Taipei 106, Taiwan R.O.C., Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei 106, Taiwan R.O.C., and Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604
| | - K. K. Liang
- Department of Chemistry, National Taiwan University, Taipei 106, Taiwan R.O.C., Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei 106, Taiwan R.O.C., and Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604
| | - R. Chang
- Department of Chemistry, National Taiwan University, Taipei 106, Taiwan R.O.C., Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei 106, Taiwan R.O.C., and Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604
| | - S. H. Lin
- Department of Chemistry, National Taiwan University, Taipei 106, Taiwan R.O.C., Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei 106, Taiwan R.O.C., and Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604
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Spörlein S, Zinth W, Meyer M, Scheer H, Wachtveitl J. Primary electron transfer in modified bacterial reaction centers: optimization of the first events in photosynthesis. Chem Phys Lett 2000. [DOI: 10.1016/s0009-2614(00)00471-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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