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Zazubovich V, Jankowiak R. High-Resolution Frequency-Domain Spectroscopic and Modeling Studies of Photosystem I (PSI), PSI Mutants and PSI Supercomplexes. Int J Mol Sci 2024; 25:3850. [PMID: 38612659 PMCID: PMC11011720 DOI: 10.3390/ijms25073850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 03/23/2024] [Accepted: 03/26/2024] [Indexed: 04/14/2024] Open
Abstract
Photosystem I (PSI) is one of the two main pigment-protein complexes where the primary steps of oxygenic photosynthesis take place. This review describes low-temperature frequency-domain experiments (absorption, emission, circular dichroism, resonant and non-resonant hole-burned spectra) and modeling efforts reported for PSI in recent years. In particular, we focus on the spectral hole-burning studies, which are not as common in photosynthesis research as the time-domain spectroscopies. Experimental and modeling data obtained for trimeric cyanobacterial Photosystem I (PSI3), PSI3 mutants, and PSI3-IsiA18 supercomplexes are analyzed to provide a more comprehensive understanding of their excitonic structure and excitation energy transfer (EET) processes. Detailed information on the excitonic structure of photosynthetic complexes is essential to determine the structure-function relationship. We will focus on the so-called "red antenna states" of cyanobacterial PSI, as these states play an important role in photochemical processes and EET pathways. The high-resolution data and modeling studies presented here provide additional information on the energetics of the lowest energy states and their chlorophyll (Chl) compositions, as well as the EET pathways and how they are altered by mutations. We present evidence that the low-energy traps observed in PSI are excitonically coupled states with significant charge-transfer (CT) character. The analysis presented for various optical spectra of PSI3 and PSI3-IsiA18 supercomplexes allowed us to make inferences about EET from the IsiA18 ring to the PSI3 core and demonstrate that the number of entry points varies between sample preparations studied by different groups. In our most recent samples, there most likely are three entry points for EET from the IsiA18 ring per the PSI core monomer, with two of these entry points likely being located next to each other. Therefore, there are nine entry points from the IsiA18 ring to the PSI3 trimer. We anticipate that the data discussed below will stimulate further research in this area, providing even more insight into the structure-based models of these important cyanobacterial photosystems.
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Affiliation(s)
- Valter Zazubovich
- Department of Physics, Concordia University, Montreal, QC H4B 1R6, Canada
| | - Ryszard Jankowiak
- Department of Chemistry, Kansas State University, Manhattan, KS 66506, USA
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Trempe A, Levenberg A, Ortega ADG, Lujan MA, Picorel R, Zazubovich V. Effects of Chlorophyll Triplet States on the Kinetics of Spectral Hole Growth. J Phys Chem B 2021; 125:3278-3285. [PMID: 33764072 DOI: 10.1021/acs.jpcb.0c09042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Spectral hole burning has been employed for decades to study various amorphous solids and proteins. Triplet states and respective transient holes were incorporated into theoretical models and software simulating nonphotochemical spectral hole burning (NPHB) and including all relevant distributions, in particular the distribution of the angle between the electric field of light E and transient dipole moment of the chromophore μ. The presence of a chlorophyll a triplet state with a lifetime of several milliseconds explains the slowdown of NPHB (on the depth vs illumination dose scale) with the increase of the light intensity, as well as larger hole depths observed in weak probe beam experiments, compared to those deduced from the hole growth kinetics (HGK) measurements (signal collected at a fixed wavelength while a stronger burning beam is on) in cytochrome b6f and chemically modified LH2. We also considered the solvent deuteration effects on triplet lifetime and concluded that both triplet states and local heating likely play a role in slowing down the HGK with increasing burn intensity.
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Affiliation(s)
- Alexandra Trempe
- Department of Physics, Concordia University, 7141 Sherbrooke Str. West, Montreal, Quebec H4B 1R6, Canada
| | - Alexander Levenberg
- Department of Physics, Concordia University, 7141 Sherbrooke Str. West, Montreal, Quebec H4B 1R6, Canada
| | | | - Maria A Lujan
- Estacion Experimental de Aula Dei (CSIC), Avda. Montañana 1005, Zaragoza 50059, Spain
| | - Rafael Picorel
- Estacion Experimental de Aula Dei (CSIC), Avda. Montañana 1005, Zaragoza 50059, Spain
| | - Valter Zazubovich
- Department of Physics, Concordia University, 7141 Sherbrooke Str. West, Montreal, Quebec H4B 1R6, Canada
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Shafiei G, Levenberg A, Lujan MA, Picorel R, Zazubovich V. Evidence of Simultaneous Spectral Hole Burning Involving Two Tiers of the Protein Energy Landscape in Cytochrome b6f. J Phys Chem B 2019; 123:10930-10938. [PMID: 31763829 DOI: 10.1021/acs.jpcb.9b09515] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cytochrome b6f, with one chlorophyll molecule per protein monomer, is a simple model system whose studies can help achieve a better understanding of nonphotochemical spectral hole burning (NPHB) and single-complex spectroscopy results obtained in more complicated photosynthetic chlorophyll-protein complexes. We are reporting new data and proposing an alternative explanation for spectral dynamics that was recently observed in cytochrome b6f using NPHB. The relevant distribution of the tunneling parameter λ is a superposition of two components that are nearly degenerate in terms of the resultant NPHB yield and represent two tiers of the energy landscape responsible for NPHB. These two components likely burn competitively; we present the first demonstration of modeling a competitive NPHB process. Similar values of the NPHB yield result from distinctly different combinations of barrier heights, shifts along the generalized coordinate d, and/or masses of the entities involved in conformational changes m, with md2 parameter different by a factor of 2.7. Consequently, in cytochrome b6f, the first (at least) 10 h of fixed-temperature recovery preferentially probe different components of the barrier- and λ-distributions encoded into the spectral holes than thermocycling experiments. Both components most likely represent dynamics of the protein and not of the surrounding buffer/glycerol glass.
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Affiliation(s)
- Golia Shafiei
- Department of Physics , Concordia University , 7141 Sherbrooke Str. West , Montreal , Quebec H4B 1R6 , Canada
| | - Alexander Levenberg
- Department of Physics , Concordia University , 7141 Sherbrooke Str. West , Montreal , Quebec H4B 1R6 , Canada
| | - Maria A Lujan
- Estacion Experimental de Aula Dei (CSIC) , Avda. Montañana 1005 , 50059 Zaragoza , Spain
| | - Rafael Picorel
- Estacion Experimental de Aula Dei (CSIC) , Avda. Montañana 1005 , 50059 Zaragoza , Spain
| | - Valter Zazubovich
- Department of Physics , Concordia University , 7141 Sherbrooke Str. West , Montreal , Quebec H4B 1R6 , Canada
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Levenberg A, Shafiei G, Lujan MA, Giannacopoulos S, Picorel R, Zazubovich V. Probing Energy Landscapes of Cytochrome b 6f with Spectral Hole Burning: Effects of Deuterated Solvent and Detergent. J Phys Chem B 2017; 121:9848-9858. [PMID: 28956922 DOI: 10.1021/acs.jpcb.7b07686] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In non-photochemical spectral hole burning (NPHB) and spectral hole recovery experiments, cytochrome b6f protein exhibits behavior that is almost independent of the deuteration of the buffer/glycerol glassy matrix containing the protein, apart from some differences in heat dissipation. On the other hand, strong dependence of the hole burning properties on sample preparation procedures was observed and attributed to a large increase of the electron-phonon coupling and shortening of the excited-state lifetime occurring when n-dodecyl β-d-maltoside (DM) is used as a detergent instead of n-octyl β-d-glucopyranoside (OGP). The data was analyzed assuming that the tunneling parameter distribution or barrier distribution probed by NPHB and encoded into the spectral holes contains contributions from two nonidentical components with accidentally degenerate excited state λ-distributions. Both components likely reflect protein dynamics, although with some small probability one of them (with larger md2) may still represent the dynamics involving specifically the -OH groups of the water/glycerol solvent. Single proton tunneling in the water/glycerol solvent environment or in the protein can be safely excluded as the origin of observed NPHB and hole recovery dynamics. The intensity dependence of the hole growth kinetics in deuterated samples likely reflects differences in heat dissipation between protonated and deuterated samples. These differences are most probably due to the higher interface thermal resistivity between (still protonated) protein and deuterated water/glycerol outside environment.
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Affiliation(s)
- Alexander Levenberg
- Department of Physics, Concordia University , 7141 Sherbrooke Street West, Montreal, Quebec H4B 1R6, Canada
| | - Golia Shafiei
- Department of Physics, Concordia University , 7141 Sherbrooke Street West, Montreal, Quebec H4B 1R6, Canada
| | - Maria A Lujan
- Estacion Experimental de Aula Dei (CSIC) , Avda. Montañana 1005, 50059 Zaragoza, Spain
| | - Steven Giannacopoulos
- Department of Physics, Concordia University , 7141 Sherbrooke Street West, Montreal, Quebec H4B 1R6, Canada
| | - Rafael Picorel
- Estacion Experimental de Aula Dei (CSIC) , Avda. Montañana 1005, 50059 Zaragoza, Spain
| | - Valter Zazubovich
- Department of Physics, Concordia University , 7141 Sherbrooke Street West, Montreal, Quebec H4B 1R6, Canada
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5
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Najafi M, Herascu N, Shafiei G, Picorel R, Zazubovich V. Conformational Changes in Pigment–Protein Complexes at Low Temperatures—Spectral Memory and a Possibility of Cooperative Effects. J Phys Chem B 2015; 119:6930-40. [PMID: 25985255 DOI: 10.1021/acs.jpcb.5b02845] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mehdi Najafi
- Department
of Physics, Concordia University, 7141 Sherbrooke Street West, Montreal, Quebec H4B 1R6, Canada
| | - Nicoleta Herascu
- Department
of Physics, Concordia University, 7141 Sherbrooke Street West, Montreal, Quebec H4B 1R6, Canada
| | - Golia Shafiei
- Department
of Physics, Concordia University, 7141 Sherbrooke Street West, Montreal, Quebec H4B 1R6, Canada
| | - Rafael Picorel
- Estacion Experimental de Aula Dei (CSIC), Avda. Montañana 1005, 50059 Zaragoza, Spain
| | - Valter Zazubovich
- Department
of Physics, Concordia University, 7141 Sherbrooke Street West, Montreal, Quebec H4B 1R6, Canada
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6
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Najafi M, Herascu N, Seibert M, Picorel R, Jankowiak R, Zazubovich V. Spectral Hole Burning, Recovery, and Thermocycling in Chlorophyll–Protein Complexes: Distributions of Barriers on the Protein Energy Landscape. J Phys Chem B 2012; 116:11780-90. [DOI: 10.1021/jp308055r] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mehdi Najafi
- Department of Physics, Concordia University, 7141 Sherbrooke Str. West, Montreal,
Quebec H4B 1R6 Canada
| | - Nicoleta Herascu
- Department of Physics, Concordia University, 7141 Sherbrooke Str. West, Montreal,
Quebec H4B 1R6 Canada
| | - Michael Seibert
- National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Rafael Picorel
- Estacion Experimental de Aula Dei (CSIC), Avda. Montañana 1005, 50002
Zaragoza, Spain
| | - Ryszard Jankowiak
- Department
of Chemistry, Kansas State University,
Manhattan, Kansas 66505, United
States
| | - Valter Zazubovich
- Department of Physics, Concordia University, 7141 Sherbrooke Str. West, Montreal,
Quebec H4B 1R6 Canada
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7
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Herascu N, Ahmouda S, Picorel R, Seibert M, Jankowiak R, Zazubovich V. Effects of the Distributions of Energy or Charge Transfer Rates on Spectral Hole Burning in Pigment–Protein Complexes at Low Temperatures. J Phys Chem B 2011; 115:15098-109. [DOI: 10.1021/jp208142k] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Nicoleta Herascu
- Department of Physics, Concordia University, 7141 Sherbrooke Street West, Montreal, Quebec H4B 1R6 Canada
| | - Somaya Ahmouda
- Department of Physics, Concordia University, 7141 Sherbrooke Street West, Montreal, Quebec H4B 1R6 Canada
| | - Rafael Picorel
- Estacion Experimental Aula Dei (CSIC), Avda. Montañana, 50059 Zaragoza, Spain
- National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Michael Seibert
- National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Ryszard Jankowiak
- Department of Chemistry, Kansas State University, Manhattan, Kansas 66506, United States
| | - Valter Zazubovich
- Department of Physics, Concordia University, 7141 Sherbrooke Street West, Montreal, Quebec H4B 1R6 Canada
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8
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Jankowiak R, Reppert M, Zazubovich V, Pieper J, Reinot T. Site Selective and Single Complex Laser-Based Spectroscopies: A Window on Excited State Electronic Structure, Excitation Energy Transfer, and Electron–Phonon Coupling of Selected Photosynthetic Complexes. Chem Rev 2011; 111:4546-98. [DOI: 10.1021/cr100234j] [Citation(s) in RCA: 122] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ryszard Jankowiak
- Department of Chemistry, Kansas State University, Manhattan, Kansas 66506, United States
| | - Mike Reppert
- Department of Chemistry, Kansas State University, Manhattan, Kansas 66506, United States
| | - Valter Zazubovich
- Department of Physics, Concordia University, Montreal H4B1R6 Quebec, Canada
| | - Jörg Pieper
- Max-Volmer-Laboratories for Biophysical Chemistry, Technical University of Berlin, Germany
- Institute of Physics, University of Tartu, Riia 142, 51014 Tartu, Estonia
| | - Tonu Reinot
- Department of Chemistry, Kansas State University, Manhattan, Kansas 66506, United States
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9
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Grozdanov D, Herascu N, Reinot T, Jankowiak R, Zazubovich V. Low-temperature protein dynamics of the B800 molecules in the LH2 light-harvesting complex: spectral hole burning study and comparison with single photosynthetic complex spectroscopy. J Phys Chem B 2010; 114:3426-38. [PMID: 20166717 DOI: 10.1021/jp9089358] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Previously published and new spectral hole burning (SHB) data on the B800 band of LH2 light-harvesting antenna complex of Rps. acidophila are analyzed in light of recent single photosynthetic complex spectroscopy (SPCS) results (for a review, see Berlin et al. Phys. Life Rev. 2007, 4, 64.). It is demonstrated that, in general, SHB-related phenomena observed for the B800 band are in qualitative agreement with the SPCS data and the protein models involving multiwell multitier protein energy landscapes. Regarding the quantitative agreement, we argue that the single-molecule behavior associated with the fastest spectral diffusion (smallest barrier) tier of the protein energy landscape is inconsistent with the SHB data. The latter discrepancy can be attributed to SPCS probing not only the dynamics of of the protein complex per se, but also that of the surrounding amorphous host and/or of the host-protein interface. It is argued that SHB (once improved models are developed) should also be able to provide the average magnitudes and probability distributions of light-induced spectral shifts and could be used to determine whether SPCS probes a set of protein complexes that are both intact and statistically relevant. SHB results are consistent with the B800 --> B850 energy-transfer models including consideration of the whole B850 density of states.
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Affiliation(s)
- Daniel Grozdanov
- Department of Physics, Concordia University, 7141 Sherbrooke Street West, Montreal, Quebec H4B 1R6, Canada
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10
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Dang NC, Reinot T, Reppert M, Jankowiak R. Temperature Dependence of Hole Growth Kinetics in Aluminum−Phthalocyanine−Tetrasulfonate in Hyperquenched Glassy Water. J Phys Chem B 2007; 111:1582-9. [PMID: 17256889 DOI: 10.1021/jp065958g] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The temperature (T) dependence of hole growth kinetics (HGK) data that span more than four decades of burn fluence are reported for aluminum-phthalocyanine tetrasulfonate (APT) in fresh and annealed hyperquenched glassy water (HGW) for temperatures between 5 and 20 K. The highly dispersive HGK data are modeled by using the "master" equation based on the two level system (TLS) model described in 2000 by Reinot and Small [J. Chem. Phys. 2000, 113, 10207]. We have demonstrated that thermal line broadening is not enough to account for temperature-dependent HGK for temperatures greater than 10 K. To overcome the discrepancy, the hole growth model must account for thermal hole filling (THF) processes. For the first time, the "master" equation used for HGK simulations is modified to take into account both the temperature dependence of the (single site) absorption spectrum and THF processes, effectively turning off those TLS which do not participate in the hole burning process at higher temperatures. A single set of parameters, some of which were determined directly from the hole spectra, was found to provide satisfactory fits to the HGK data for APT in fresh and annealed HGW for holes burned in the 679.7-676.9 nm range from the high to low energy sides of the Qx absorption band. Furthermore, we propose that HGK modeling at high burn fluences requires that the TLS model be further modified to take into account the existence of extrinsic multiple level systems.
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Affiliation(s)
- N C Dang
- Department of Chemistry, Kansas State University, Manhattan, Kansas 66506, USA
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11
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Matsuzaki S, Hayes JM, Benbrook DM, Jankowiak R. Nonphotochemical Hole-Burning Study of Selectively Stained Normal and Cancerous Human Ovarian Tissues. J Phys Chem B 2006; 110:16124-30. [PMID: 16898770 DOI: 10.1021/jp060114i] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Results are presented of nonphotochemical hole-burning (HB) experiments on cancerous ovarian and analogous normal peritoneal in vitro tissues stained with the mitochondrial-selective dye rhodamine 800. A comparison of fluorescence excitation spectra, hole-growth kinetics data, and external electric field (Stark) effects on the shape of spectral holes burned in cancerous and normal tissues stained with rhodamine 800 revealed significant differences only in the dipole moment change (fDeltamu) measured by a combination of HB and Stark spectroscopies. It is shown that the permanent dipole moment change for the S0--> S1 transition of the rhodamine 800 molecules in cancerous tissue is higher than that of normal tissue by a factor of about 1.4. The finding is similar to the HB results obtained earlier for human ovarian surface epithelial cell lines, i.e., OV167 carcinoma and OSE(tsT)-14 normal cells stained with the same mitochondria-specific dye (Walsh et al. Biophys. J. 2003, 84, 1299). We propose that the observed difference in the permanent dipole moment change in cancerous ovarian tissue is related to a modification in mitochondrial membrane potential.
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Affiliation(s)
- S Matsuzaki
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73190, USA
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12
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Riley K, Jankowiak R, Rätsep M, Small GJ, Zazubovich V. Evidence for Highly Dispersive Primary Charge Separation Kinetics and Gross Heterogeneity in the Isolated PS II Reaction Center of Green Plants. J Phys Chem B 2004. [DOI: 10.1021/jp049562l] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- K. Riley
- Ames Laboratory, USDOE and Department of Chemistry, Iowa State University, Ames, Iowa 50011, and Institute of Physics, University of Tartu, 142 Riia Street, 51014 Tartu, Estonia
| | - R. Jankowiak
- Ames Laboratory, USDOE and Department of Chemistry, Iowa State University, Ames, Iowa 50011, and Institute of Physics, University of Tartu, 142 Riia Street, 51014 Tartu, Estonia
| | - M. Rätsep
- Ames Laboratory, USDOE and Department of Chemistry, Iowa State University, Ames, Iowa 50011, and Institute of Physics, University of Tartu, 142 Riia Street, 51014 Tartu, Estonia
| | - G. J. Small
- Ames Laboratory, USDOE and Department of Chemistry, Iowa State University, Ames, Iowa 50011, and Institute of Physics, University of Tartu, 142 Riia Street, 51014 Tartu, Estonia
| | - V. Zazubovich
- Ames Laboratory, USDOE and Department of Chemistry, Iowa State University, Ames, Iowa 50011, and Institute of Physics, University of Tartu, 142 Riia Street, 51014 Tartu, Estonia
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13
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Dispersive hole growth kinetics and fluence broadening of the zero-phonon hole of impurities in amorphous hosts. Chem Phys 2004. [DOI: 10.1016/j.chemphys.2003.09.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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14
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Reinot T, Dang NC, Small GJ. A model for persistent hole burned spectra and hole growth kinetics that includes photoproduct absorption: Application to free base phthalocyanine in hyperquenched glassy ortho-dichlorobenzene at 5 K. J Chem Phys 2003. [DOI: 10.1063/1.1605371] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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15
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Walsh RJ, Reinot T, Hayes JM, Kalli KR, Hartmann LC, Small GJ. Carcinoma and SV40-transfected normal ovarian surface epithelial cell comparison by nonphotochemical hole burning. Biophys J 2003; 84:1299-307. [PMID: 12547810 PMCID: PMC1302706 DOI: 10.1016/s0006-3495(03)74945-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Results are presented of nonphotochemical-hole-burning experiments on the mitochondrial specific dye rhodamine 800 incubated with two human ovarian surface epithelial cell lines: OSE(tsT)-14 normal cells and OV167 carcinoma cells. This dye is selective for the plasma and inner membranes of the mitochondria, as shown by confocal microscopy images. Dispersive hole-growth kinetics of zero-phonon holes are analyzed with theoretical fits, indicating that subcellular structural heterogeneity of the carcinoma cell line is lower relative to the analogous normal cell line. Broadening of holes in the presence of an applied electric field (Stark effect) was used to determine the permanent dipole moment change for the S(0)-->S(1) transition in the two cell lines. For the carcinoma cell line, the permanent dipole moment change value is a factor of 1.5 higher than for the normal cell line. It is speculated that this difference may be related to differences in mitochondrial membrane potentials in the two cell lines.
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Affiliation(s)
- R J Walsh
- Ames Laboratory--USDOE, Iowa State University, Ames, Iowa 50011, USA
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16
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Reinot T, Small GJ. Non-Lorentzian zero-phonon holes and new insights on nonphotochemical hole burning: Al-phthalocyanine in hyperquenched glassy water. J Chem Phys 2001. [DOI: 10.1063/1.1367259] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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17
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Reinot T, Zazubovich V, Hayes JM, Small GJ. New Insights on Persistent Nonphotochemical Hole Burning and Its Application to Photosynthetic Complexes. J Phys Chem B 2001. [DOI: 10.1021/jp010126y] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Tonu Reinot
- Department of Chemistry and Ames Laboratory-U.S. Department of Energy, Iowa State University, Ames, Iowa 50011
| | - Valter Zazubovich
- Department of Chemistry and Ames Laboratory-U.S. Department of Energy, Iowa State University, Ames, Iowa 50011
| | - John M. Hayes
- Department of Chemistry and Ames Laboratory-U.S. Department of Energy, Iowa State University, Ames, Iowa 50011
| | - Gerald J. Small
- Department of Chemistry and Ames Laboratory-U.S. Department of Energy, Iowa State University, Ames, Iowa 50011
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