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Kumar N, Murli C, Varma M, Poswal HK, Thomas S, Kshirsagar RJ. High pressure Raman investigation on trans-urocanic acid. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2022; 266:120438. [PMID: 34627016 DOI: 10.1016/j.saa.2021.120438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 08/27/2021] [Accepted: 09/22/2021] [Indexed: 06/13/2023]
Abstract
Trans-urocanic acid (t-UCA) is an important epidermal UV protector predominantly found in human skin. Exposure of UV radiation triggers photoisomerization of t-UCA into its other conformer, cis-urocanic acid (cis-UCA), which has been shown to be a mediator of UV-induced immune-suppression leading to skin cancer. In this report, we present the investigation of molecular changes of t-UCA under high pressures by in-situ high pressure Raman spectroscopy. The study indicates onset of ring opening polymerization of t-UCA at pressure above 1.4 GPa. At pressures beyond 5 GPa, a well discernible characteristic vibrational mode (CC stretch) accompanied by several other spectral features such as δ CO2- and δ NH modes of cis-UCA point towards the isomerization of residual t-UCA monomers into cis-UCA. The content of cis-UCA gradually increased with increase in pressure. On release to ambient conditions, the spectrum of the quenched sample showed Raman modes of polymer and cis-UCA indicating that the changes are irreversible.
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Affiliation(s)
- Naveen Kumar
- Infrared Laser Spectroscopy Section, Bhabha Atomic Research Centre, Trombay, Mumbai 85, India; Homi Bhabha National Institute, Anushaktinagar, Mumbai 94, India.
| | - C Murli
- High Pressure & Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 85, India; Homi Bhabha National Institute, Anushaktinagar, Mumbai 94, India
| | - Meera Varma
- High Pressure & Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 85, India
| | - H K Poswal
- High Pressure & Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 85, India; Homi Bhabha National Institute, Anushaktinagar, Mumbai 94, India
| | - S Thomas
- High Pressure & Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 85, India.
| | - R J Kshirsagar
- Infrared Laser Spectroscopy Section, Bhabha Atomic Research Centre, Trombay, Mumbai 85, India; Homi Bhabha National Institute, Anushaktinagar, Mumbai 94, India
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2
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Sharifian A, Abyar F, Behjatmanesh-Ardakani R. Electronic structure and characterization of the spectra of trans/cis tautomers of urocanic acid isomers: A diagnostic tool. J Photochem Photobiol A Chem 2020. [DOI: 10.1016/j.jphotochem.2020.112652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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3
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Tuna D, Spörkel L, Barbatti M, Thiel W. Nonadiabatic dynamics simulations of photoexcited urocanic acid. Chem Phys 2018. [DOI: 10.1016/j.chemphys.2018.09.036] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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4
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Cuadrado S, Goicoechea JR, Roncero O, Aguado A, Tercero B, Cernicharo J. Trans-cis molecular photoswitching in interstellar Space. ASTRONOMY AND ASTROPHYSICS 2016; 596:L1. [PMID: 28003686 PMCID: PMC5166968 DOI: 10.1051/0004-6361/201629913] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
As many organic molecules, formic acid (HCOOH) has two conformers (trans and cis). The energy barrier to internal conversion from trans to cis is much higher than the thermal energy available in molecular clouds. Thus, only the most stable conformer (trans) is expected to exist in detectable amounts. We report the first interstellar detection of cis-HCOOH. Its presence in ultraviolet (UV) irradiated gas exclusively (the Orion Bar photodissociation region), with a low trans-to-cis abundance ratio of 2.8 ± 1.0, supports a photoswitching mechanism: a given conformer absorbs a stellar photon that radiatively excites the molecule to electronic states above the interconversion barrier. Subsequent fluorescent decay leaves the molecule in a different conformer form. This mechanism, which we specifically study with ab initio quantum calculations, was not considered in Space before but likely induces structural changes of a variety of interstellar molecules submitted to UV radiation.
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Affiliation(s)
- S Cuadrado
- Grupo de Astrofísica Molecular. Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), Sor Juana Ines de la Cruz 3, E-28049 Cantoblanco, Madrid, Spain
| | - J R Goicoechea
- Grupo de Astrofísica Molecular. Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), Sor Juana Ines de la Cruz 3, E-28049 Cantoblanco, Madrid, Spain
| | - O Roncero
- Instituto de Física Fundamental (IFF-CSIC). Calle Serrano 123, E-28006 Madrid, Spain
| | - A Aguado
- Facultad de Ciencias, Unidad Asociada de Química-Física Aplicada CSIC-UAM, Universidad Autónoma de Madrid, E-28049, Madrid, Spain
| | - B Tercero
- Grupo de Astrofísica Molecular. Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), Sor Juana Ines de la Cruz 3, E-28049 Cantoblanco, Madrid, Spain
| | - J Cernicharo
- Grupo de Astrofísica Molecular. Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), Sor Juana Ines de la Cruz 3, E-28049 Cantoblanco, Madrid, Spain
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5
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Zhao L, Zhou PW, Zhao GJ. Non-adiabatic dynamics investigation of the radiationless decay mechanism of trans-urocanic acid in the S2 state. J Chem Phys 2016; 145:044316. [DOI: 10.1063/1.4959131] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Affiliation(s)
- Li Zhao
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- University of the Chinese Academy of Sciences, Beijing 100049, People’s Republic of China
| | - Pan-Wang Zhou
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Guang-Jiu Zhao
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
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6
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Tuna D, Sobolewski AL, Domcke W. Photochemical Mechanisms of Radiationless Deactivation Processes in Urocanic Acid. J Phys Chem B 2014; 118:976-85. [DOI: 10.1021/jp411818j] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Deniz Tuna
- Department
of Chemistry, Technische Universität München, Lichtenbergstr.
4, 85747 Garching, Germany
| | - Andrzej L. Sobolewski
- Institute
of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02668 Warsaw, Poland
| | - Wolfgang Domcke
- Department
of Chemistry, Technische Universität München, Lichtenbergstr.
4, 85747 Garching, Germany
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7
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Hu Y, Guan J, Bernstein ER. Mass-selected IR-VUV (118 nm) spectroscopic studies of radicals, aliphatic molecules, and their clusters. MASS SPECTROMETRY REVIEWS 2013; 32:484-501. [PMID: 24122973 DOI: 10.1002/mas.21387] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 04/25/2013] [Accepted: 04/25/2013] [Indexed: 06/02/2023]
Abstract
Mass-selected IR plus UV/VUV spectroscopy and mass spectrometry have been coupled into a powerful technique to investigate chemical, physical, structural, and electronic properties of radicals, molecules, and clusters. Advantages of the use of vacuum ultraviolet (VUV) radiation to create ions for mass spectrometry are its application to nearly all compounds with ionization potentials below the energy of a single VUV photon, its circumventing the requirement of UV chromophore group, its inability to ionize background gases, and its greatly reduced fragmenting capabilities. In this review, mass-selected IR plus VUV (118 nm) spectroscopy is introduced first in a general manner. Selected application examples of this spectroscopy are presented, which include the detections and structural analysis of radicals, molecules, and molecular clusters in a supersonic jet.
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Affiliation(s)
- Yongjun Hu
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou, 510631, China
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8
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Godfrey PD, Robertson EG. Microwave spectrum, structure, tautomeric, and conformational composition of 4-vinylimidazole. J Chem Phys 2012; 137:064306. [DOI: 10.1063/1.4742061] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
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9
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Barbatti M. The role of tautomers in the UV absorption of urocanic acid. Phys Chem Chem Phys 2011; 13:4686. [DOI: 10.1039/c0cp02142c] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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10
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Tiwari S, Chand Mishra P. Urocanic acid as an efficient hydroxyl radical scavenger: a quantum theoretical study. J Mol Model 2010; 17:59-72. [DOI: 10.1007/s00894-010-0699-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2009] [Accepted: 02/25/2010] [Indexed: 11/30/2022]
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11
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Rand AA, Barclay LRC. Photo-oxidations initiated by UV radiation of urocanic acid and its methyl ester in solution, micelles, and lipid bilayers: TYPE I (free radical) or TYPE II (singlet oxygen) mechanisms depend on the medium. J Photochem Photobiol A Chem 2009. [DOI: 10.1016/j.jphotochem.2009.08.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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12
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Hu Y, Bernstein ER. Vibrational and photoionization spectroscopy of biomolecules: Aliphatic amino acid structures. J Chem Phys 2008; 128:164311. [DOI: 10.1063/1.2902980] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
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13
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14
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Gibbs NK, Tye J, Norval M. Recent advances in urocanic acid photochemistry, photobiology and photoimmunology. Photochem Photobiol Sci 2008; 7:655-67. [PMID: 18528548 DOI: 10.1039/b717398a] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Urocanic acid (UCA), produced in the upper layers of mammalian skin, is a major absorber of ultraviolet radiation (UVR). Originally thought to be a 'natural sunscreen', studies conducted a quarter of a century ago proposed that UCA may be a chromophore for the immunosuppression that follows exposure to UVR. With its intriguing photochemistry, its role in immunosuppression and skin cancer development, and skin barrier function, UCA continues to be the subject of intense research effort. This review summarises the photochemical, photobiological and photoimmunological findings regarding UCA, published since 1998.
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Affiliation(s)
- Neil K Gibbs
- Dermatological Sciences, University of Manchester Medical School, Stopford Building, Oxford Road, Manchester, UK M13 9PT.
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15
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Zhao GJ, Han KL, Lei YB, Dou YS. Ultrafast excited-state dynamics of tetraphenylethylene studied by semiclassical simulation. J Chem Phys 2007; 127:094307. [PMID: 17824739 DOI: 10.1063/1.2768347] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Detailed simulation study is reported for the excited-state dynamics of photoisomerization of cis-tetraphenylethylene (TPE) following excitation by a femtosecond laser pulse. The technique for this investigation is semiclassical dynamics simulation, which is described briefly in the paper. Upon photoexcitation by a femtosecond laser pulse, the stretching motion of the ethylenic bond of TPE is initially excited, leading to a significant lengthening of ethylenic bond in 300 fs. Twisting motion about the ethylenic bond is activated by the energy released from the relaxation of the stretching mode. The 90 degrees twisting about the ethylenic bond from an approximately planar geometry to nearly a perpendicular conformation in the electronically excited state is completed in 600 fs. The torsional dynamics of phenyl rings which is temporally lagging behind occurs at about 5 ps. Finally, the twisted TPE reverts to the initial conformation along the twisting coordinate through nonadiabatic transitions. The simulation results provide a basis for understanding several spectroscopic observations at molecular levels, including ultrafast dynamic Stokes shift, multicomponent fluorescence, viscosity dependence of the fluorescence lifetime, and radiationless decay from electronically excited state to the ground state along the isomerization coordinate.
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Affiliation(s)
- Guang-Jiu Zhao
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, People's Republic of China
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16
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Barclay LRC, Basque MC, Stephenson VC, Vinqvist MR. Photooxidations Initiated or Sensitized by Biological Molecules: Singlet Oxygen Versus Radical Peroxidation in Micelles and Human Blood Plasma ¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2003)0780248piosbb2.0.co2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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17
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Menon EL, Morrison H. Formation of Singlet Oxygen by Urocanic Acid by UVA Irradiation and Some Consequences Thereof¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2002)0750565fosobu2.0.co2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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18
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Menon EL, Perera R, Kuhn RJ, Morrison H. Reactive Oxygen Species Formation by UV-A Irradiation of Urocanic Acid and the Role of Trace Metals in This Chemistry¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2003)0780567rosfbu2.0.co2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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19
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Wallis RA, Smith GJ, Dunford CL. The Effect of Molecular Environment on the Photoisomerization of Urocanic Acid¶. Photochem Photobiol 2007. [DOI: 10.1111/j.1751-1097.2004.tb00080.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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20
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Ahn S, Cong X, Lebrilla CB, Gronert S. Zwitterion formation in gas-phase cyclodextrin complexes. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2005; 16:166-175. [PMID: 15694767 DOI: 10.1016/j.jasms.2004.10.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2004] [Revised: 10/19/2004] [Accepted: 10/22/2004] [Indexed: 05/24/2023]
Abstract
Protonated complexes of amino acids and underivatized beta-cyclodextrin, produced by electrospray ionization and trapped in the Fourier transform mass spectrometer, undergo formation of ternary complexes when reacted with alkyl amine. Based on the reactivities of the protonated amino acid complexes with alkylamines, the reactivities of the corresponding amino acid esters, and partially derivatized beta-cyclodextrin hosts, we conclude that the ternary complexes are salt-bridge zwitterionic species composed of amino acid zwitterions and protonated alkylamine all interacting with the hydroxyl groups on the narrow rim of the cyclodextrin. Molecular modeling calculations and experimental results suggest that the interactions of the amino acids with the rims contribute greatly to the formation of the zwitterionic species.
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Affiliation(s)
- Seonghee Ahn
- Department of Chemistry, School of Medicine, University of California at Davis, Davis, California 95616, USA
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21
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Dmitrenko O, Reischl W, Bach RD, Spanget-Larsen J. TD-DFT Computational Insight into the Origin of Wavelength-Dependent E/Z Photoisomerization of Urocanic Acid. J Phys Chem A 2004. [DOI: 10.1021/jp0499530] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Olga Dmitrenko
- Brown Laboratory, Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, Institute of Organic Chemistry, University of Vienna, A-1090 Vienna, Austria, and Department of Life Sciences and Chemistry, Roskilde University, DK-4000 Roskilde, Denmark
| | - Wolfgang Reischl
- Brown Laboratory, Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, Institute of Organic Chemistry, University of Vienna, A-1090 Vienna, Austria, and Department of Life Sciences and Chemistry, Roskilde University, DK-4000 Roskilde, Denmark
| | - Robert D. Bach
- Brown Laboratory, Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, Institute of Organic Chemistry, University of Vienna, A-1090 Vienna, Austria, and Department of Life Sciences and Chemistry, Roskilde University, DK-4000 Roskilde, Denmark
| | - Jens Spanget-Larsen
- Brown Laboratory, Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, Institute of Organic Chemistry, University of Vienna, A-1090 Vienna, Austria, and Department of Life Sciences and Chemistry, Roskilde University, DK-4000 Roskilde, Denmark
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22
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Wallis RA, Smith GJ, Dunford CL. The Effect of Molecular Environment on the Photoisomerization of Urocanic Acid¶. Photochem Photobiol 2004. [DOI: 10.1562/2004-05-11-ra-163.1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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23
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Ko C, Levine B, Toniolo A, Manohar L, Olsen S, Werner HJ, Martínez TJ. Ab Initio Excited-State Dynamics of the Photoactive Yellow Protein Chromophore. J Am Chem Soc 2003; 125:12710-1. [PMID: 14558810 DOI: 10.1021/ja0365025] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The photoisomerization mechanism of the neutral form of the photoactive yellow protein (PYP) chromophore is investigated using ab initio quantum chemistry and first-principles nonadiabatic molecular dynamics (ab initio multiple spawning or AIMS). We identify the nature of the two lowest-lying excited states, characterize the short-time behavior of molecules excited directly to S2, and explain the origin of the experimentally observed wavelength-dependent photoisomerization quantum yield.
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Affiliation(s)
- Chaehyuk Ko
- Department of Chemistry and The Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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24
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Danielsson J, Laaksonen A. Gas phase photoisomerization of urocanic acid – a theoretical study. Chem Phys Lett 2003. [DOI: 10.1016/s0009-2614(03)00170-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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25
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Barclay LR, Basque MC, Stephenson VC, Vinqvist MR. Photooxidations Initiated or Sensitized by Biological Molecules: Singlet Oxygen Versus Radical Peroxidation in Micelles and Human Blood Plasma¶. Photochem Photobiol 2003; 78:248-55. [PMID: 14556311 DOI: 10.1562/0031-8655(2003)078<0248:piosbb>2.0.co;2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Biomolecules common in blood plasma, including 2-methyl-1,4-naphthoquinone (vitamin K-0, 2), 2,3-dimethoxy-5-methyl-1,4-benzoquinone (ubiquinone-0, 3), bilirubin, 4, and urocanic acid, 5, were used as photoactivators for the photooxidation of methyl linoleate (ML) in 0.50 M sodium dodecyl sulfate micelles to mimic a bioenvironment. UV irradiation of 2 in this system initiated H-atom abstraction from ML (Type-I mechanism). The evidence includes kinetics of oxygen uptake, inhibition of oxidation by an antioxidant ((R)-(+)-6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid [Trolox], 7) and the analysis of four geometric hydroperoxides formed (cis, trans to trans, trans ratio of 0.5). In contrast, irradiation with a singlet-oxygen sensitizer, 3,5-di-t-butyl-1,2-benzoquinone, 1, formed six isomers by a Type-II mechanism, yielding a cis, trans to trans, trans isomer ratio of 6. Peroxidation activated by 3 or 4 with visible light occurred by a singlet-oxygen pathway (Type-II mechanism), as shown by kinetics of oxygen uptake and the effect of quenchers. In contrast, peroxidation in the presence of 5 in this system initiated H-atom abstraction from ML as shown by oxygen uptake and inhibition by Trolox. A comparison of thermal free-radical peroxidation with direct photooxidation of human blood plasma samples showed important differences. Blood plasma resisted thermal peroxidation because of natural antioxidants or on the addition of Trolox. In contrast, direct photooxidation involved singlet oxygen, according to the effect of quenchers and the lack of inhibition by antioxidants.
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Affiliation(s)
- L Ross Barclay
- Department of Chemistry, Mount Allison University, Sackville, New Brunswick, Canada, E4L 1G8.
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Menon EL, Perera R, Kuhn RJ, Morrison H. Reactive Oxygen Species Formation by UV-A Irradiation of Urocanic Acid and the Role of Trace Metals in This Chemistry¶. Photochem Photobiol 2003; 78:567-75. [PMID: 14743864 DOI: 10.1562/0031-8655(2003)078<0567:rosfbu>2.0.co;2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We have extended our study of the decomposition of urocanic acid (UCA) with ultraviolet A radiation (UV-A) by the self-sensitized generation of singlet oxygen (see Photochem. Photobiol. 75, 565 [2002]). The chemistry has been found to be partially dependent on the presence of trace metal, most likely iron. Rigorous removal of metal impurities from the reaction mixture, using Chelex, retarded (but did not eliminate) the UV-A-initiated UCA degradation. The addition of small amounts of ferric chloride to the Chelex-treated solutions restored reactivity. Chelex treatment had a modest effect on the previously reported ability of UCA photoproducts to photonick supercoiled plasmid DNA. Also, photoinactivation of Sindbis virus on irradiation with the UCA photoproducts is now reported. Inactivation of the virus by a photoproduct mixture derived from a UCA solution that had been pretreated with Chelex was less rapid and gave better behaved time-course plots than was observed for photoproducts from non-Chelex treated solutions. These results are particularly noteworthy in light of the ubiquitous presence of both UCA and iron in the skin.
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Affiliation(s)
- Elton L Menon
- Department of Chemistry, Purdue University, West Lafayette, IN 47097-2084, USA
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27
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Mohammad T. Laser-induced in vitro isomerization of urocanic acid in UVA region and the origin of excited triplet state. Tetrahedron Lett 2002. [DOI: 10.1016/s0040-4039(02)02210-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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28
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Abbott JE, Peng X, Kong W. Symmetry properties of electronically excited states of nitroaromatic compounds. J Chem Phys 2002. [DOI: 10.1063/1.1513992] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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29
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DANIELSSON JONAS, SÖDERHÄLL JARVID, LAAKSONEN AATTO. Hydration structure and conformational dynamics of urocanic acid: a computer simulation study. Mol Phys 2002. [DOI: 10.1080/00268970210125340] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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30
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Abstract
Singlet oxygen-initiated decomposition of urocanic acid (UCA) (3-(1H-imidazol-4(5)-yl)-2-propenoic acid) was used to successfully confirm the report that UCA generates singlet oxygen when irradiated with ultraviolet A light (UVA). The UCA-generated singlet oxygen converts UCA to one or more products that then catalyze the further destruction of the UCA with UVA light by singlet oxygen formation. Some nicking of the phiX-174 supercoiled plasmid DNA was observed when UCA was irradiated with UVA to complete destruction of the starting material, and the product mixture was then mixed with the plasmid in the dark. More extensive nicking was seen when the photoproduct mixture and the plasmid were irradiated with UVA light. An "aged" (4 days) solution of UCA photoproduct no longer caused nicking in the dark but retained the capability to nick the plasmid when irradiated. There is evidence for the presence of hydroperoxides in the UCA photolysis product mixture, and the quenching studies with 2-propanol indicate that free radicals are involved in the plasmid-nicking photochemistry. Singlet oxygen does not appear to play a role in the nicking of the plasmid.
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Affiliation(s)
- Elton L Menon
- Department of Chemistry, Purdue University, West Lafayette, IN 47097-1393, USA
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31
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Brookman J, Chacón JN, Sinclair RS. Some photophysical studies of cis- and trans-urocanic acid. Photochem Photobiol Sci 2002; 1:327-32. [PMID: 12653471 DOI: 10.1039/b201621d] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Urocanic acid, an important human skin chromophore, undergoes a variety of photochemical transformations when exposed to the near-UV portion of sunlight and natural daylight, the principal reaction being the transformation from the stable trans- or (E)-form of the chromophore (trans-UA) to the biologically active cis- or (Z)-form (cis-UA), which is claimed to induce immunosuppression linked to the onset of skin cancer. This study is concerned with the comparative photophysical behaviour of the two urocanic acid isomers in aqueous solution using both continuous irradiation and pulsed irradiation techniques. The UV absorption maximum for both isomers occurs in the region of 270 nm with the absorption shape varying characteristically with pH, the cis-isomer showing a lower overall molar absorptivity. Both isomers exhibit weak fluorescence (quantum yields estimated to be less than 10(-4)) with each isomer showing small differences in the way in which pH and excitation wavelength influence the fluorescence emission characteristics. Pulsed nanosecond laser irradiation at 266 nm of aqueous solutions at pH 7 shows that both isomers undergo photo-ionisation with a quantum yield of 0.02 for the hydrated electron production, a quantum yield value comparable with that for photoisomerisation at this wavelength. Laser flash studies also show that the photo-ionised species reacts efficiently with oxygen (quenching rate kQ = 1.3 x 10(9) M(-1) s(-1)), while some preliminary experiments indicate that both cis- and trans-urocanic acids react with the semiquinone radical of L-3,4-dihydroxyphenylalanine (L-DOPA) with a fast reaction rate constant of approximately 5 x 10(7) M(-1) s(-1). The photophysical characteristics of trans-UA and cis-UA reported here are discussed in the context of other recent pulsed irradiation studies on urocanic acid over nanosecond and picosecond time scales, in an attempt to clarify the complex photo-behaviour of this interesting biomolecule.
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Affiliation(s)
- Jennifer Brookman
- Division of Chemistry and Chemical Engineering, University of Paisley, High Street, Paisley Renfrewshire, Scotland, UK
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Danielsson J, Ulicný J, Laaksonen A. A TD-DFT study of the photochemistry of urocanic acid in biologically relevant ionic, rotameric, and protomeric forms. J Am Chem Soc 2001; 123:9817-21. [PMID: 11583543 DOI: 10.1021/ja0158051] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The photochemistry of Urocanic acid, a chromophore present in human skin and linked to photoimmunosuppression and skin cancer, is investigated theoretically by means of time-dependent density functional theory. Extensive calculations are carried out for different ionic, rotameric, and protomeric forms of both the trans and cis form. Inclusion of solvation effects, here accounted for by means of a continuum solvent model, are found to be crucial for the correct description of the biologically relevant zwitterionic forms of the molecule. For the trans zwitterionic form, it is found that the planar form usually assumed in the literature is not stable, and that a realistic charge separation cannot be achieved in the gas phase. Calculated vertical excitation energies are in excellent agreement with available experimental data, with a weakly absorbing n --> pi transition around 4.0 eV, and strongly absorbing pi --> pi transitions at 4.5-4.9 eV. The debated intramolecular hydrogen bond is predicted to have a modest impact on the vertical spectra in solution, but improves agreement with experiment when included. In general, we also predict that different rotameric forms have very similar absorption spectra. In addition, we find a candidate absorbing state to link trans-urocanic acid to singlet oxygen production and subsequent photoaging of the skin.
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Affiliation(s)
- J Danielsson
- Division of Physical Chemistry, Arrhenius Laboratory, Stockholm University, S 106 91, Stockholm, Sweden
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