1
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Ashworth EK, Kao MH, Anstöter CS, Riesco-Llach G, Blancafort L, Solntsev KM, Meech SR, Verlet JRR, Bull JN. Alkylated green fluorescent protein chromophores: dynamics in the gas phase and in aqueous solution. Phys Chem Chem Phys 2023; 25:23626-23636. [PMID: 37649445 DOI: 10.1039/d3cp03250g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
Fluorescent labelling of macromolecular samples, including using the green fluorescent protein (GFP), has revolutionised the field of bioimaging. The ongoing development of fluorescent proteins require a detailed understanding of the photophysics of the biochromophore, and how chemical derivatisation influences the excited state dynamics. Here, we investigate the photophysical properties associated with the S1 state of three alkylated derivatives of the chromophore in GFP, in the gas phase using time-resolved photoelectron imaging, and in water using femtosecond fluorescence upconversion. The gas-phase lifetimes (1.6-10 ps), which are associated with the intrinsic (environment independent) dynamics, are substantially longer than the lifetimes in water (0.06-3 ps), attributed to stabilisation of both twisted intermediate structures and conical intersection seams in the condensed phase. In the gas phase, alkylation on the 3 and 5 positions of the phenyl ring slows the dynamics due to inertial effects, while a 'pre-twist' of the methine bridge through alkylation on the 2 and 6 positions significantly shortens the excited state lifetimes. Formation of a minor, long-lived (≫ 40 ps) excited state population in the gas phase is attributed to intersystem crossing to a triplet state, accessed because of a T1/S1 degeneracy in the so-called P-trap potential energy minimum associated with torsion of the single-bond in the bridging unit connecting to the phenoxide ring. A small amount of intersystem crossing is supported through TD-DFT molecular dynamics trajectories and MS-CASPT2 calculations. No such intersystem crossing occurs in water at T = 300 K or in ethanol at T ≈ 77 K, due to a significantly altered potential energy surface and P-trap geometry.
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Affiliation(s)
- Eleanor K Ashworth
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich, NR4 7TJ, UK.
| | - Min-Hsien Kao
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich, NR4 7TJ, UK.
| | - Cate S Anstöter
- Department of Chemistry, Durham University, Durham, DH1 3LE, UK
| | - Gerard Riesco-Llach
- Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, C/M.A. Capmany 69, 17003 Girona, Spain
| | - Lluís Blancafort
- Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, C/M.A. Capmany 69, 17003 Girona, Spain
| | - Kyril M Solntsev
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Stephen R Meech
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich, NR4 7TJ, UK.
| | - Jan R R Verlet
- Department of Chemistry, Durham University, Durham, DH1 3LE, UK
| | - James N Bull
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich, NR4 7TJ, UK.
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2
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Chen MS, Mao Y, Snider A, Gupta P, Montoya-Castillo A, Zuehlsdorff TJ, Isborn CM, Markland TE. Elucidating the Role of Hydrogen Bonding in the Optical Spectroscopy of the Solvated Green Fluorescent Protein Chromophore: Using Machine Learning to Establish the Importance of High-Level Electronic Structure. J Phys Chem Lett 2023; 14:6610-6619. [PMID: 37459252 DOI: 10.1021/acs.jpclett.3c01444] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/28/2023]
Abstract
Hydrogen bonding interactions with chromophores in chemical and biological environments play a key role in determining their electronic absorption and relaxation processes, which are manifested in their linear and multidimensional optical spectra. For chromophores in the condensed phase, the large number of atoms needed to simulate the environment has traditionally prohibited the use of high-level excited-state electronic structure methods. By leveraging transfer learning, we show how to construct machine-learned models to accurately predict the high-level excitation energies of a chromophore in solution from only 400 high-level calculations. We show that when the electronic excitations of the green fluorescent protein chromophore in water are treated using EOM-CCSD embedded in a DFT description of the solvent the optical spectrum is correctly captured and that this improvement arises from correctly treating the coupling of the electronic transition to electric fields, which leads to a larger response upon hydrogen bonding between the chromophore and water.
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Affiliation(s)
- Michael S Chen
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Yuezhi Mao
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Andrew Snider
- Chemistry and Biochemistry, University of California Merced, Merced, California 95343, United States
| | - Prachi Gupta
- Chemistry and Biochemistry, University of California Merced, Merced, California 95343, United States
| | - Andrés Montoya-Castillo
- Department of Chemistry, University of Colorado, Boulder, Boulder, Colorado 80309, United States
| | - Tim J Zuehlsdorff
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, United States
| | - Christine M Isborn
- Chemistry and Biochemistry, University of California Merced, Merced, California 95343, United States
| | - Thomas E Markland
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
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3
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Li J, Li N. Revisit on the assignment of electronic spectra of C11H9+ isomers. COMPUT THEOR CHEM 2023. [DOI: 10.1016/j.comptc.2023.114028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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4
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List NH, Jones CM, Martínez TJ. Internal conversion of the anionic GFP chromophore: in and out of the I-twisted S 1/S 0 conical intersection seam. Chem Sci 2022; 13:373-385. [PMID: 35126970 PMCID: PMC8729814 DOI: 10.1039/d1sc05849e] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2021] [Accepted: 11/11/2021] [Indexed: 11/21/2022] Open
Abstract
The functional diversity of the green fluorescent protein (GFP) family is intimately connected to the interplay between competing photo-induced transformations of the chromophore motif, anionic p-hydroxybenzylidene-2,3-dimethylimidazolinone (HBDI-). Its ability to undergo Z/E-isomerization is of particular importance for super-resolution microscopy and emerging opportunities in optogenetics. Yet, key dynamical features of the underlying internal conversion process in the native HBDI- chromophore remain largely elusive. We investigate the intrinsic excited-state behavior of isolated HBDI- to resolve competing decay pathways and map out the factors governing efficiency and the stereochemical outcome of photoisomerization. Based on non-adiabatic dynamics simulations, we demonstrate that non-selective progress along the two bridge-torsional (i.e., phenolate, P, or imidazolinone, I) pathways accounts for the three decay constants reported experimentally, leading to competing ultrafast relaxation primarily along the I-twisted pathway and S1 trapping along the P-torsion. The majority of the population (∼70%) is transferred to S0 in the vicinity of two approximately enantiomeric minima on the I-twisted intersection seam (MECI-Is). Despite their sloped, reactant-biased topographies (suggesting low photoproduct yields), we find that decay through these intersections leads to products with a surprisingly high quantum yield of ∼30%. This demonstrates that E-isomer generation results at least in part from direct isomerization on the excited state. A photoisomerization committor analysis reveals a difference in intrinsic photoreactivity of the two MECI-Is and that the observed photoisomerization is the combined result of two effects: early, non-statistical dynamics around the less reactive intersection followed by later, near-statistical behavior around the more reactive MECI-I. Our work offers new insight into internal conversion of HBDI- that both establishes the intrinsic properties of the chromophore and enlightens principles for the design of chromophore derivatives and protein variants with improved photoswitching properties.
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Affiliation(s)
- Nanna H List
- Department of Chemistry and the PULSE Institute, Stanford University Stanford CA 94305 USA .,SLAC National Accelerator Laboratory 2575 Sand Hill Road Menlo Park CA 94025 USA
| | - Chey M Jones
- Department of Chemistry and the PULSE Institute, Stanford University Stanford CA 94305 USA .,SLAC National Accelerator Laboratory 2575 Sand Hill Road Menlo Park CA 94025 USA
| | - Todd J Martínez
- Department of Chemistry and the PULSE Institute, Stanford University Stanford CA 94305 USA .,SLAC National Accelerator Laboratory 2575 Sand Hill Road Menlo Park CA 94025 USA
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5
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Grigorenko BL, Domratcheva T, Polyakov IV, Nemukhin AV. Protonation States of Molecular Groups in the Chromophore-Binding Site Modulate Properties of the Reversibly Switchable Fluorescent Protein rsEGFP2. J Phys Chem Lett 2021; 12:8263-8271. [PMID: 34424693 DOI: 10.1021/acs.jpclett.1c02415] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The role of protonation states of the chromophore and its neighboring amino acid side chains of the reversibly switching fluorescent protein rsEGFP2 upon photoswitching is characterized by molecular modeling methods. Numerous conformations of the chromophore-binding site in computationally derived model systems are obtained using the quantum chemistry and QM/MM approaches. Excitation energies are computed using the extended multiconfigurational quasidegenerate perturbation theory (XMCQDPT2). The obtained structures and absorption spectra allow us to provide an interpretation of the observed structural and spectral properties of rsEGFP2 in the active ON and inactive OFF states. The results demonstrate that in addition to the dominating anionic and neutral forms of the chromophore, the cationic and zwitterionic forms may participate in the photoswitching of rsEGFP2. Conformations and protonation forms of the Glu223 and His149 side chains in the chromophore-binding site play an essential role in stabilizing specific protonation forms of the chromophore.
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Affiliation(s)
- Bella L Grigorenko
- Department of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow 119334, Russia
| | - Tatiana Domratcheva
- Department of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
- Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany
| | - Igor V Polyakov
- Department of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow 119334, Russia
| | - Alexander V Nemukhin
- Department of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow 119334, Russia
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6
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Raucci U, Perrella F, Donati G, Zoppi M, Petrone A, Rega N. Ab-initio molecular dynamics and hybrid explicit-implicit solvation model for aqueous and nonaqueous solvents: GFP chromophore in water and methanol solution as case study. J Comput Chem 2020; 41:2228-2239. [PMID: 32770577 DOI: 10.1002/jcc.26384] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 06/21/2020] [Accepted: 06/27/2020] [Indexed: 12/15/2022]
Abstract
Solute-solvent interactions are proxies for understanding how the electronic density of a chromophore interacts with the environment in a more exhaustive way. The subtle balance between polarization, electrostatic, and non-bonded interactions need to be accurately described to obtain good agreement between simulations and experiments. First principles approaches providing accurate configurational sampling through molecular dynamics may be a suitable choice to describe solvent effects on solute chemical-physical properties and spectroscopic features, such as optical absorption of dyes. In this context, accurate energy potentials, obtained by hybrid implicit/explicit solvation methods along with employing nonperiodic boundary conditions, are required to represent bulk solvent around a large solute-solvent cluster. In this work, a novel strategy to simulate methanol solutions is proposed combining ab initio molecular dynamics, a hybrid implicit/explicit flexible solvent model, nonperiodic boundary conditions, and time dependent density functional theory. As case study, the robustness of the proposed protocol has been gauged by investigating the microsolvation and electronic absorption of the anionic green fluorescent protein chromophore in methanol and aqueous solution. Satisfactory results are obtained, reproducing the microsolvation layout of the chromophore and, as a consequence, the experimental trends shown by the optical absorption in different solvents.
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Affiliation(s)
- Umberto Raucci
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario di M.S. Angelo, Naples, Italy
| | - Fulvio Perrella
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario di M.S. Angelo, Naples, Italy
| | - Greta Donati
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario di M.S. Angelo, Naples, Italy.,Dipartimento di Chimica e Biologia "Adolfo Zambelli", Università di Salerno, Fisciano, Italy
| | - Maria Zoppi
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario di M.S. Angelo, Naples, Italy
| | - Alessio Petrone
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario di M.S. Angelo, Naples, Italy
| | - Nadia Rega
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario di M.S. Angelo, Naples, Italy.,Center for Advanced Biomaterials for Healthcare@CRIB, Naples, Italy
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7
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Romei MG, Lin CY, Mathews II, Boxer SG. Electrostatic control of photoisomerization pathways in proteins. Science 2020; 367:76-79. [PMID: 31896714 DOI: 10.1126/science.aax1898] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 06/04/2019] [Accepted: 10/31/2019] [Indexed: 12/23/2022]
Abstract
Rotation around a specific bond after photoexcitation is central to vision and emerging opportunities in optogenetics, super-resolution microscopy, and photoactive molecular devices. Competing roles for steric and electrostatic effects that govern bond-specific photoisomerization have been widely discussed, the latter originating from chromophore charge transfer upon excitation. We systematically altered the electrostatic properties of the green fluorescent protein chromophore in a photoswitchable variant, Dronpa2, using amber suppression to introduce electron-donating and electron-withdrawing groups to the phenolate ring. Through analysis of the absorption (color), fluorescence quantum yield, and energy barriers to ground- and excited-state isomerization, we evaluate the contributions of sterics and electrostatics quantitatively and demonstrate how electrostatic effects bias the pathway of chromophore photoisomerization, leading to a generalized framework to guide protein design.
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Affiliation(s)
- Matthew G Romei
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA.
| | - Chi-Yun Lin
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA.
| | - Irimpan I Mathews
- Stanford Synchrotron Radiation Lightsource, Menlo Park, CA 94025, USA
| | - Steven G Boxer
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
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8
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Lin CY, Romei MG, Oltrogge LM, Mathews II, Boxer SG. Unified Model for Photophysical and Electro-Optical Properties of Green Fluorescent Proteins. J Am Chem Soc 2019; 141:15250-15265. [PMID: 31450887 DOI: 10.1021/jacs.9b07152] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Green fluorescent proteins (GFPs) have become indispensable imaging and optogenetic tools. Their absorption and emission properties can be optimized for specific applications. Currently, no unified framework exists to comprehensively describe these photophysical properties, namely the absorption maxima, emission maxima, Stokes shifts, vibronic progressions, extinction coefficients, Stark tuning rates, and spontaneous emission rates, especially one that includes the effects of the protein environment. In this work, we study the correlations among these properties from systematically tuned GFP environmental mutants and chromophore variants. Correlation plots reveal monotonic trends, suggesting that all these properties are governed by one underlying factor dependent on the chromophore's environment. By treating the anionic GFP chromophore as a mixed-valence compound existing as a superposition of two resonance forms, we argue that this underlying factor is defined as the difference in energy between the two forms, or the driving force, which is tuned by the environment. We then introduce a Marcus-Hush model with the bond length alternation vibrational mode, treating the GFP absorption band as an intervalence charge transfer band. This model explains all of the observed strong correlations among photophysical properties; related subtopics are extensively discussed in the Supporting Information. Finally, we demonstrate the model's predictive power by utilizing the additivity of the driving force. The model described here elucidates the role of the protein environment in modulating the photophysical properties of the chromophore, providing insights and limitations for designing new GFPs with desired phenotypes. We argue that this model should also be generally applicable to both biological and nonbiological polymethine dyes.
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Affiliation(s)
- Chi-Yun Lin
- Department of Chemistry , Stanford University , Stanford , California 94305 , United States
| | - Matthew G Romei
- Department of Chemistry , Stanford University , Stanford , California 94305 , United States
| | - Luke M Oltrogge
- Department of Chemistry , Stanford University , Stanford , California 94305 , United States
| | - Irimpan I Mathews
- Stanford Synchrotron Radiation Lightsource , 2575 Sand Hill Road , Menlo Park , California 94025 , United States
| | - Steven G Boxer
- Department of Chemistry , Stanford University , Stanford , California 94305 , United States
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9
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Avila Ferrer FJ, Angeli C, Cerezo J, Coriani S, Ferretti A, Santoro F. The Intriguing Case of the One‐Photon and Two‐Photon Absorption of a Prototypical Symmetric Squaraine: Comparison of TDDFT and Wave‐Function Methods. CHEMPHOTOCHEM 2019. [DOI: 10.1002/cptc.201900121] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
| | - Celestino Angeli
- Dipartimento di Scienze Chimiche e FarmaceuticheUniversità di Ferrara via Borsari 46 44121 Ferrara Italy
| | - Javier Cerezo
- Departamento de Química, Facultad de Ciencias, Módulo 13Universidad Autónoma de Madrid, Campus de Excelencia UAM-CSIC, Cantoblanco 28049 Madrid Spain
| | - Sonia Coriani
- DTU ChemistryTechnical University of Denmark, Kemitorvet Building 207 DK-2800 Kongens Lyngby Denmark
| | - Alessandro Ferretti
- Istituto di Chimica dei Composti Organometallici (ICCOM-CNR) Area della Ricerca del CNR, Via Moruzzi 1 I-56124 Pisa
| | - Fabrizio Santoro
- Istituto di Chimica dei Composti Organometallici (ICCOM-CNR) Area della Ricerca del CNR, Via Moruzzi 1 I-56124 Pisa
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10
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Zuehlsdorff TJ, Isborn CM. Combining the ensemble and Franck-Condon approaches for calculating spectral shapes of molecules in solution. J Chem Phys 2018; 148:024110. [PMID: 29331131 DOI: 10.1063/1.5006043] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The correct treatment of vibronic effects is vital for the modeling of absorption spectra of many solvated dyes. Vibronic spectra for small dyes in solution can be easily computed within the Franck-Condon approximation using an implicit solvent model. However, implicit solvent models neglect specific solute-solvent interactions on the electronic excited state. On the other hand, a straightforward way to account for solute-solvent interactions and temperature-dependent broadening is by computing vertical excitation energies obtained from an ensemble of solute-solvent conformations. Ensemble approaches usually do not account for vibronic transitions and thus often produce spectral shapes in poor agreement with experiment. We address these shortcomings by combining zero-temperature vibronic fine structure with vertical excitations computed for a room-temperature ensemble of solute-solvent configurations. In this combined approach, all temperature-dependent broadening is treated classically through the sampling of configurations and quantum mechanical vibronic contributions are included as a zero-temperature correction to each vertical transition. In our calculation of the vertical excitations, significant regions of the solvent environment are treated fully quantum mechanically to account for solute-solvent polarization and charge-transfer. For the Franck-Condon calculations, a small amount of frozen explicit solvent is considered in order to capture solvent effects on the vibronic shape function. We test the proposed method by comparing calculated and experimental absorption spectra of Nile red and the green fluorescent protein chromophore in polar and non-polar solvents. For systems with strong solute-solvent interactions, the combined approach yields significant improvements over the ensemble approach. For systems with weak to moderate solute-solvent interactions, both the high-energy vibronic tail and the width of the spectra are in excellent agreement with experiments.
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Affiliation(s)
- T J Zuehlsdorff
- School of Natural Sciences, University of California Merced, N. Lake Road, Merced, California 95344, USA
| | - C M Isborn
- School of Natural Sciences, University of California Merced, N. Lake Road, Merced, California 95344, USA
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11
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Chen F, Zhao X, Liang W. One- and two-photon absorption spectra of the yellow fluorescent protein citrine: effects of intramolecular electron-vibrational coupling and intermolecular interactions. Mol Phys 2018. [DOI: 10.1080/00268976.2018.1426130] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Fasheng Chen
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, Xiamen, China
- Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
| | - Xinyi Zhao
- Department of Science and Technology for Inspection, Xiamen Huaxia University, Xiamen, China
| | - WanZhen Liang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, Xiamen, China
- Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
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12
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Nabavi SH, Khodabandeh MH, Golbabaee M, Moshaii A, Davari MD. Excited states study reveals the twisted geometry induced large stokes shift in DCM fluorescent dye. J Photochem Photobiol A Chem 2018. [DOI: 10.1016/j.jphotochem.2017.05.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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13
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Zutterman F, Liégeois V, Champagne B. Simulation of the UV/Visible Absorption Spectra of Fluorescent Protein Chromophore Models. CHEMPHOTOCHEM 2017. [DOI: 10.1002/cptc.201700002] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Freddy Zutterman
- Laboratoire de Chimie Théorique, Unité de Chimie-Physique Théorique et Structurale; Université de Namur; rue de Bruxelles, 61 B-5000 Namur Belgium
| | - Vincent Liégeois
- Laboratoire de Chimie Théorique, Unité de Chimie-Physique Théorique et Structurale; Université de Namur; rue de Bruxelles, 61 B-5000 Namur Belgium
| | - Benoît Champagne
- Laboratoire de Chimie Théorique, Unité de Chimie-Physique Théorique et Structurale; Université de Namur; rue de Bruxelles, 61 B-5000 Namur Belgium
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14
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Drink E, Dugourd P, Dumont E, Aronssohn N, Antoine R, Loison C. Optical properties of prodigiosin and obatoclax: action spectroscopy and theoretical calculations. Phys Chem Chem Phys 2016; 17:25946-55. [PMID: 26120608 DOI: 10.1039/c5cp01498k] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Prodiginine molecules (prodigiosin and obatoclax) are well-known pH-chromic dyes with promising anti-tumor properties. They present multiple tautomeric and rotameric forms. The protonation state and the structure of such flexible ligands in interaction with a protein are crucial to understand and to model the protein's biological activities. The determination of the protonation state via UV/vis absorption is possible if the ligand spectra of the neutral and protonated states are sufficiently different, and also if we can eliminate other factors potentially impacting the spectrum. Upon measuring the absorption spectra of the ligand in solution, varying solvents and pH values, we have determined that the optical properties of prodigiosin and obatoclax depend on the protonation state and not on the solvent permittivity constant. In parallel, action spectroscopy (using tunable lasers coupled to ion traps) in the gas phase of protonated and sodiated prodigiosin and obatoclax molecules has been performed to evaluate the sensitivity of the charge and the conformational state to their optical properties free of solvent. The spectra are interpreted using computational simulations of molecular structures and electronic excitations. The excitation energies are only slightly sensitive to various isomerizations, and may be used to distinguish between protonated and deprotonated states, even in the presence of a sodium counter-ion.
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Affiliation(s)
- Evangeline Drink
- Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne cedex, France.
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15
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Santoro F, Jacquemin D. Going beyond the vertical approximation with time-dependent density functional theory. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2016. [DOI: 10.1002/wcms.1260] [Citation(s) in RCA: 121] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Fabrizio Santoro
- CNR-Consiglio Nazionale delle Ricerche; Istituto di Chimica dei Composti OrganoMetallici (ICCOM-CNR); Pisa Italy
| | - Denis Jacquemin
- CEISAM, UMR CNRS 6230; Université de Nantes; Nantes France
- Institut Universitaire de France; Paris France
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16
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Cerezo J, Avila Ferrer FJ, Santoro F. Disentangling vibronic and solvent broadening effects in the absorption spectra of coumarin derivatives for dye sensitized solar cells. Phys Chem Chem Phys 2015; 17:11401-11. [DOI: 10.1039/c5cp00370a] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Individuation of vibronic and solvent contributions to the spectra of a family of coumarin dyes helps to understand the main differences in their lineshapes.
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Affiliation(s)
- Javier Cerezo
- CNR–Consiglio Nazionale delle Ricerche
- Istituto di Chimica dei Composti Organo Metallici (ICCOM-CNR)
- UOS di Pisa
- Area della Ricerca
- I-56124 Pisa
| | - Francisco J. Avila Ferrer
- CNR–Consiglio Nazionale delle Ricerche
- Istituto di Chimica dei Composti Organo Metallici (ICCOM-CNR)
- UOS di Pisa
- Area della Ricerca
- I-56124 Pisa
| | - Fabrizio Santoro
- CNR–Consiglio Nazionale delle Ricerche
- Istituto di Chimica dei Composti Organo Metallici (ICCOM-CNR)
- UOS di Pisa
- Area della Ricerca
- I-56124 Pisa
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