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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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2
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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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3
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Fufina TY, Selikhanov GK, Proskuryakov II, Shuvalov VA, Vasilieva LG. Properties of Rhodobacter sphaeroides Reaction Centers with the Ile→Tyr Substitution at Positions L177 and M206. BIOCHEMISTRY (MOSCOW) 2019; 84:570-574. [PMID: 31234771 DOI: 10.1134/s0006297919050110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Studying pigment-protein interactions in the photosynthetic reaction centers (RCs) is important for the understanding of detailed mechanisms of the photochemical process. This paper describes spectral and photochemical characteristics, pigment composition, and stability of the Rhodobacter sphaeroides RCs with the I(L177)Y and I(M206)Y amino acid substitutions. The obtained data are compared with the properties of I(L177)H, I(L177)D, and I(M206)H RCs reported previously. It is shown that the I(L177)Y and I(M206)Y mutations cause a similar shift of the QYP band in the absorption spectra of the mutant RCs and do not affect the distribution of the electron spin density within the photo-oxidized P+ dimer. The differences in the position and amplitude of the QYB band in the I(L177)Y and I(M206)Y RCs were determined. The results indicate the possibility of new pigment-protein interactions in the vicinity of monomeric bacteriochlorophylls in the A and B chains, which might be of interest for future research.
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Affiliation(s)
- T Yu Fufina
- Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia.
| | - G K Selikhanov
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia
| | - I I Proskuryakov
- Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia
| | - V A Shuvalov
- Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia
| | - L G Vasilieva
- Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia
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4
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Fufina TY, Leonova MM, Khatypov RA, Khristin AM, Shuvalov VA, Vasilieva LG. Features of Bacteriochlorophylls Axial Ligation in the Photosynthetic Reaction Center of Purple Bacteria. BIOCHEMISTRY (MOSCOW) 2019; 84:370-379. [DOI: 10.1134/s0006297919040047] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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5
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Stability and properties of quasi-stable conformational states in the LH2 light-harvesting complex of Rbl. acidophilus bacteria formed by hexacoordination of bacteriochlorophyll a magnesium atom. Chem Phys 2017. [DOI: 10.1016/j.chemphys.2017.04.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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6
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Saer RG, Stadnytskyi V, Magdaong NC, Goodson C, Savikhin S, Blankenship RE. Probing the excitonic landscape of the Chlorobaculum tepidum Fenna-Matthews-Olson (FMO) complex: a mutagenesis approach. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2017; 1858:288-296. [PMID: 28159567 DOI: 10.1016/j.bbabio.2017.01.011] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 01/27/2017] [Accepted: 01/30/2017] [Indexed: 12/17/2022]
Abstract
In this paper we report the steady-state optical properties of a series of site-directed mutants in the Fenna-Matthews-Olson (FMO) complex of Chlorobaculum tepidum, a photosynthetic green sulfur bacterium. The FMO antenna complex has historically been used as a model system for energy transfer due to the water-soluble nature of the protein, its stability at room temperature, as well as the availability of high-resolution structural data. Eight FMO mutants were constructed with changes in the environment of each of the bacteriochlorophyll a pigments found within each monomer of the homotrimeric FMO complex. Our results reveal multiple changes in low temperature absorption, as well as room temperature CD in each mutant compared to the wild-type FMO complex. These datasets were subsequently used to model the site energies of each pigment in the FMO complex by employing three different Hamiltonians from the literature. This enabled a basic approximation of the site energy shifts imparted on each pigment by the changed amino acid residue. These simulations suggest that, while the three Hamiltonians used in this work provide good fits to the wild-type FMO absorption spectrum, further efforts are required to obtain good fits to the mutant minus wild-type absorption difference spectra. This demonstrates that the use of FMO mutants can be a valuable tool to refine and iterate the current models of energy transfer in this system.
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Affiliation(s)
- Rafael G Saer
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, United States; Photosynthetic Antenna Research Center, Washington University in St. Louis, St. Louis, MO 63130, United States
| | - Valentyn Stadnytskyi
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN 47907, United States
| | - Nikki C Magdaong
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, United States; Photosynthetic Antenna Research Center, Washington University in St. Louis, St. Louis, MO 63130, United States; Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, United States
| | - Carrie Goodson
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, United States
| | - Sergei Savikhin
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN 47907, United States
| | - Robert E Blankenship
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, United States; Photosynthetic Antenna Research Center, Washington University in St. Louis, St. Louis, MO 63130, United States; Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, United States.
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7
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Vermaas JV, Taguchi AT, Dikanov SA, Wraight CA, Tajkhorshid E. Redox potential tuning through differential quinone binding in the photosynthetic reaction center of Rhodobacter sphaeroides. Biochemistry 2015; 54:2104-16. [PMID: 25734689 DOI: 10.1021/acs.biochem.5b00033] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ubiquinone forms an integral part of the electron transport chain in cellular respiration and photosynthesis across a vast number of organisms. Prior experimental results have shown that the photosynthetic reaction center (RC) from Rhodobacter sphaeroides is only fully functional with a limited set of methoxy-bearing quinones, suggesting that specific interactions with this substituent are required to drive electron transport and the formation of quinol. The nature of these interactions has yet to be determined. Through parameterization of a CHARMM-compatible quinone force field and subsequent molecular dynamics simulations of the quinone-bound RC, we have investigated and characterized the interactions of the protein with the quinones in the Q(A) and Q(B) sites using both equilibrium simulation and thermodynamic integration. In particular, we identify a specific interaction between the 2-methoxy group of ubiquinone in the Q(B) site and the amide nitrogen of GlyL225 that we implicate in locking the orientation of the 2-methoxy group, thereby tuning the redox potential difference between the quinones occupying the Q(A) and Q(B) sites. Disruption of this interaction leads to weaker binding in a ubiquinone analogue that lacks a 2-methoxy group, a finding supported by reverse electron transfer electron paramagnetic resonance experiments of the Q(A)⁻Q(B)⁻ biradical and competitive binding assays.
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Affiliation(s)
- Josh V Vermaas
- †Center for Biophysics and Computational Biology, ‡Department of Biochemistry, §Beckman Institute, and ∥Department of Veterinary Clinical Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Alexander T Taguchi
- †Center for Biophysics and Computational Biology, ‡Department of Biochemistry, §Beckman Institute, and ∥Department of Veterinary Clinical Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Sergei A Dikanov
- †Center for Biophysics and Computational Biology, ‡Department of Biochemistry, §Beckman Institute, and ∥Department of Veterinary Clinical Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Colin A Wraight
- †Center for Biophysics and Computational Biology, ‡Department of Biochemistry, §Beckman Institute, and ∥Department of Veterinary Clinical Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Emad Tajkhorshid
- †Center for Biophysics and Computational Biology, ‡Department of Biochemistry, §Beckman Institute, and ∥Department of Veterinary Clinical Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
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8
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Oba T, Tamiaki H. Asymmetry of chlorophylls in photosynthetic proteins: from the viewpoint of coordination chemistry. J PORPHYR PHTHALOCYA 2014. [DOI: 10.1142/s1088424614500710] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We conducted a meta-analysis of (bacterio)chlorophyll [(B)Chl] molecules in photosynthetic pigment-protein complexes from the viewpoint of coordination chemistry. We surveyed the ligand species and site in the axial coordination of 146 Chl and 21 BChl molecules in 42 reported crystal structures of 12-type proteins. The imidazolyl moiety of histidine (His) is the most abundant ligand, and the second is water, a much weaker ligand. We focused on the positions, the circumstances, and the macrocycle sides for the coordination of the 31 hydrated (B)Chl molecules found in these proteins. A ligand water molecule of a hydrated (B)Chl is not necessarily hydrogen-bonded to the surrounding protein residues. A hydrated (B)Chl seems to occupy the redundant space where more strongly coupled His-Chl complexes cannot be formed. It is noted that 28 of 31 hydrated (B)Chl molecules (90) were coordinated from the α-side of the (bacterio)chlorin macrocycle, the opposite side from which the C 17-propionic ester protrudes. Among them, all five hydrated Chl molecules at the edges of the proteins were coordinated from the α-side, suggesting that (B)Chl molecules prefer this side for the coordination bondings to the β-side. The analysis also revealed that each (B)Chl binding site was composed of both the protein residues and the neighboring pigment molecules contributing roughly equally. It can be safely said that the cofactor pigments aggregated even in the proteins. Penta-coordination is advantageous to flexible adjustment of intermolecular orientations of (B)Chl molecules in the aggregates.
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Affiliation(s)
- Toru Oba
- Department of Material and Environmental Chemistry, Graduate School of Engineering, Utsunomiya University, Utsunomiya, Tochigi 321-8585, Japan
| | - Hitoshi Tamiaki
- Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
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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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Saer RG, Hardjasa A, Rosell FI, Mauk AG, Murphy MEP, Beatty JT. Role of Rhodobacter sphaeroides Photosynthetic Reaction Center Residue M214 in the Composition, Absorbance Properties, and Conformations of HA and BA Cofactors. Biochemistry 2013; 52:2206-17. [DOI: 10.1021/bi400207m] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Rafael G. Saer
- Department
of Microbiology and Immunology and ‡Department of Biochemistry and Molecular Biology
and Centre for Blood Research, The University of British Columbia, 2350 Health Sciences Mall, Vancouver,
BC, Canada V6T 1Z3
| | - Amelia Hardjasa
- Department
of Microbiology and Immunology and ‡Department of Biochemistry and Molecular Biology
and Centre for Blood Research, The University of British Columbia, 2350 Health Sciences Mall, Vancouver,
BC, Canada V6T 1Z3
| | - Federico I. Rosell
- Department
of Microbiology and Immunology and ‡Department of Biochemistry and Molecular Biology
and Centre for Blood Research, The University of British Columbia, 2350 Health Sciences Mall, Vancouver,
BC, Canada V6T 1Z3
| | - A. Grant Mauk
- Department
of Microbiology and Immunology and ‡Department of Biochemistry and Molecular Biology
and Centre for Blood Research, The University of British Columbia, 2350 Health Sciences Mall, Vancouver,
BC, Canada V6T 1Z3
| | - Michael E. P. Murphy
- Department
of Microbiology and Immunology and ‡Department of Biochemistry and Molecular Biology
and Centre for Blood Research, The University of British Columbia, 2350 Health Sciences Mall, Vancouver,
BC, Canada V6T 1Z3
| | - J. Thomas Beatty
- Department
of Microbiology and Immunology and ‡Department of Biochemistry and Molecular Biology
and Centre for Blood Research, The University of British Columbia, 2350 Health Sciences Mall, Vancouver,
BC, Canada V6T 1Z3
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11
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Strümpfer J, Schulten K. Excited state dynamics in photosynthetic reaction center and light harvesting complex 1. J Chem Phys 2012; 137:065101. [PMID: 22897312 DOI: 10.1063/1.4738953] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Key to efficient harvesting of sunlight in photosynthesis is the first energy conversion process in which electronic excitation establishes a trans-membrane charge gradient. This conversion is accomplished by the photosynthetic reaction center (RC) that is, in case of the purple photosynthetic bacterium Rhodobacter sphaeroides studied here, surrounded by light harvesting complex 1 (LH1). The RC employs six pigment molecules to initiate the conversion: four bacteriochlorophylls and two bacteriopheophytins. The excited states of these pigments interact very strongly and are simultaneously influenced by the surrounding thermal protein environment. Likewise, LH1 employs 32 bacteriochlorophylls influenced in their excited state dynamics by strong interaction between the pigments and by interaction with the protein environment. Modeling the excited state dynamics in the RC as well as in LH1 requires theoretical methods, which account for both pigment-pigment interaction and pigment-environment interaction. In the present study we describe the excitation dynamics within a RC and excitation transfer between light harvesting complex 1 (LH1) and RC, employing the hierarchical equation of motion method. For this purpose a set of model parameters that reproduce RC as well as LH1 spectra and observed oscillatory excitation dynamics in the RC is suggested. We find that the environment has a significant effect on LH1-RC excitation transfer and that excitation transfers incoherently between LH1 and RC.
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Affiliation(s)
- Johan Strümpfer
- Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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12
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Tamiaki H, Takebe H, Sasaki SI, Kataoka Y. Synthesis of oligomethylene-strapped chlorophyll derivatives and optical properties of their stereoisomers in a solution. PHOTOSYNTHESIS RESEARCH 2012; 111:1-8. [PMID: 21253859 DOI: 10.1007/s11120-010-9616-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2010] [Accepted: 12/23/2010] [Indexed: 05/30/2023]
Abstract
Methyl pheophorbide-a/a' derivatives covalently linked with oligomethylene chains at the 3-CH(2)OCO- and 13(2)-COO- moieties in a molecule were prepared by modifying chlorophyll-a through intramolecular ring-closing metathesis of vinyl groups. At least, a C10-length between the 3(3)- and 13(4)-positions was necessary for the cyclization and connection of a C12-strap was the most suitable to achieve the highest closure yield. The oligomethylene chain in 13(2) R-epimers derived from methyl pheophorbide-a covered the α-face of the chlorin π-plane and the strap in the corresponding 13(2) S-epimers protected the β-face. Synthetic 13(2) R-epimer with a dodecamethylene chain gave a flat chlorin π-plane, while the decamethylene chain in the 13(2) R-epimer distorted the π-system due to its shorter linkage. The distortion by strapping in the 13(2) R-epimer induced a slight blue-shift of Qy peak in dichloromethane. CD spectra of the 13(2) R-epimers were similarly dependent on the chain length, i.e., the distortion of π-plane. Visible absorption and CD spectra of all the strapped 13(2) S-epimers were almost identical and only slightly different from those of the unstrapped. The strapping in the 13(2) S-epimers shifted the Qy peak bathochromically.
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Affiliation(s)
- Hitoshi Tamiaki
- Department of Bioscience and Biotechnology, Faculty of Science and Engineering, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan.
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13
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Neupane B, Jaschke P, Saer R, Beatty JT, Reppert M, Jankowiak R. Electron Transfer in Rhodobacter sphaeroides Reaction Centers Containing Zn-Bacteriochlorophylls: A Hole-Burning Study. J Phys Chem B 2012; 116:3457-66. [DOI: 10.1021/jp300304r] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - Paul Jaschke
- Department of Microbiology & Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Rafael Saer
- Department of Microbiology & Immunology, University of British Columbia, Vancouver, BC, Canada
| | - J. Thomas Beatty
- Department of Microbiology & Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Mike Reppert
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States
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14
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Vasilieva LG, Fufina TY, Gabdulkhakov AG, Leonova MM, Khatypov RA, Shuvalov VA. The site-directed mutation I(L177)H in Rhodobacter sphaeroides reaction center affects coordination of P(A) and B(B) bacteriochlorophylls. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1817:1407-17. [PMID: 22365928 DOI: 10.1016/j.bbabio.2012.02.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Revised: 01/30/2012] [Accepted: 02/08/2012] [Indexed: 11/18/2022]
Abstract
To explore the influence of the I(L177)H single mutation on the properties of the nearest bacteriochlorophylls (BChls), three reaction centers (RCs) bearing double mutations were constructed in the photosynthetic purple bacterium Rhodobacter sphaeroides, and their properties and pigment content were compared with those of the correspondent single mutant RCs. Each pair of the mutations comprised the amino acid substitution I(L177)H and another mutation altering histidine ligand of BChl P(A) or BChl B(B). Contrary to expectations, the double mutation I(L177)H+H(L173)L does not bring about a heterodimer RC but causes a 46nm blue shift of the long-wavelength P absorbance band. The histidine L177 or a water molecule were suggested as putative ligands for P(A) in the RC I(L177)H+H(L173)L although this would imply a reorientation of the His backbone and additional rearrangements in the primary donor environment or even a repositioning of the BChl dimer. The crystal structure of the mutant I(L177)H reaction center determined to a resolution of 2.9Å shows changes at the interface region between the BChl P(A) and the monomeric BChl B(B). Spectral and pigment analysis provided evidence for β-coordination of the BChl B(B) in the double mutant RC I(L177)H+H(M182)L and for its hexacoordination in the mutant reaction center I(L177)H. Computer modeling suggests involvement of two water molecules in the β-coordination of the BChl B(B). Possible structural consequences of the L177 mutation affecting the coordination of the two BChls P(A) and B(B) are discussed. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial.
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Affiliation(s)
- L G Vasilieva
- Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Moscow, Russia
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15
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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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16
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Yamijala SRKCS, Periyasamy G, Pati SK. Computational Studies on Structural and Excited-State Properties of Modified Chlorophyll f with Various Axial Ligands. J Phys Chem A 2011; 115:12298-306. [DOI: 10.1021/jp2041235] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- SRKC Sharma Yamijala
- Chemistry and Physics of Material Unit, ‡Theoretical Sciences Unit, §New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P.O., Bangalore-560 064, India
| | - Ganga Periyasamy
- Chemistry and Physics of Material Unit, ‡Theoretical Sciences Unit, §New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P.O., Bangalore-560 064, India
| | - Swapan K Pati
- Chemistry and Physics of Material Unit, ‡Theoretical Sciences Unit, §New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P.O., Bangalore-560 064, India
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17
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Fufina TY, Vasilieva LG, Khatypov RA, Shuvalov VA. Properties of Rhodobacter sphaeroides photosynthetic reaction center with double amino acid substitution I(L177)H+H(M182)L. BIOCHEMISTRY (MOSCOW) 2011; 76:450-4. [DOI: 10.1134/s0006297911040079] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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18
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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
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19
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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
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