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Penzkofer A, Silapetere A, Hegemann P. Photocycle dynamics of the Archaerhodopsin 3 based fluorescent voltage sensor Archon2. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2021; 225:112331. [PMID: 34688164 DOI: 10.1016/j.jphotobiol.2021.112331] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Revised: 09/21/2021] [Accepted: 10/05/2021] [Indexed: 11/28/2022]
Abstract
The retinal photocycle dynamics of the fluorescent voltage sensor Archon2 in pH 8 Tris buffer was studied. Archon2 is a mutant of Archaerhodopsin 3 (Arch) from Halorubrum sodomense obtained by a robotic multidimensional directed evolution approach (Archon2 = Arch T56P-P60S-T80P-D95H-T99S-T116I-F161V-T183I-L197I-A225C). The samples were photo-excited to the first absorption band of the protonated retinal Schiff base (PRSB) Ret_586 (absorption maximum at λmax = 586 nm, excitation wavelengths λexc = 590 nm and 632.8 nm). The photocycle dynamics were studied by recording absorption spectra during light exposure and after light exposure. Ret_586 photoisomerized to Ret_535 (main component) and Ret_485 (minor component). Ret_535 backward photoisomerized to Ret_586 in light-adapted state (named Ret_586la) and partly deprotonated to neutral retinal Schiff base (RSB) Ret_372 in light adapted state (named Ret_372la, same isomer form as Ret_535). After excitation light switch-off Ret_372la recovered to Ret_372 in dark-adapted state (Ret_372da) which slowly re-protonated to Ret_535, and Ret_535 slowly isomerized back to Ret_586 in dark-adapted state (Ret_586da). Photocycle schemes and reaction coordinate diagrams are developed and photocycle parameters are determined.
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Affiliation(s)
- Alfons Penzkofer
- Fakultät für Physik, Universität Regensburg, Universitätsstraße 31, D-93053 Regensburg, Germany.
| | - Arita Silapetere
- Experimentelle Biophysik, Institut für Biologie, Humboldt Universität zu Berlin, Invalidenstraße 42, D-10115 Berlin, Germany
| | - Peter Hegemann
- Experimentelle Biophysik, Institut für Biologie, Humboldt Universität zu Berlin, Invalidenstraße 42, D-10115 Berlin, Germany
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Xi W, Zhang L, Liu S, Zhao G. The Genes of CYP, ZEP, and CCD1/4 Play an Important Role in Controlling Carotenoid and Aroma Volatile Apocarotenoid Accumulation of Apricot Fruit. FRONTIERS IN PLANT SCIENCE 2020; 11:607715. [PMID: 33391319 PMCID: PMC7775601 DOI: 10.3389/fpls.2020.607715] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 12/02/2020] [Indexed: 06/12/2023]
Abstract
Carotenoids are important coloration molecules and indispensable component of the human diet. And these compounds confer most of the apricot fruit yellow or orange color. In China, fruit of some apricot cultivar present light-yellow color but strong flowery flavor, however, the chemical mechanism remains unknown. Here, carotenoids and aroma volatile apocarotenoids (AVAs) in three skin types of apricot cultivars (orange, yellow, and light-yellow skinned) were determined by HPLC and GC-MS, respectively. And the transcript levels of carotenogenic genes were analyzed by qRT-PCR. The orange-skinned cultivars "Hongyu" and "Danxing" fruit presented the most abundant total carotenoid, β-carotene and specific α-carotene contents, and β-carotene (52-77%) increased to become the dominant carotenoid during fruit ripening. The transcript levels of lycopene β-cyclase (LCYb) and β-carotene hydroxylase (CHYb) sharply increased during ripening. The yellow-skinned cultivars "Sulian No. 2" and "Akeyaleke" fruit contained lower levels of total carotenoids and β-carotene but were rich in phytoene. The light-yellow coloration of "Baixing" and "Luntaixiaobaixing" fruit was attributed to low amounts of total carotenoids, lutein, and neoxanthin and an absence of β-cryptoxanthin, but high level of aroma volatile apocarotenoids (AVAs) such as β-ionone were detected in these cultivars fruit, accompanied by low transcript levels of carotene hydroxylase (CYP) and zeaxanthin epoxidase (ZEP) but high levels of carotenoid cleavage dioxygenase 1 (CCD1) and CCD4. Correlation analysis showed that the expression level of CCD1 negatively correlated with carotenoid accumulation but positively with AVAs production. These collected results suggest that both carotenoid biosynthesis and degradation are important for apricot coloration and aroma formation. CYP, ZEP, CCD1, and CCD4 may be the key regulation points for carotenoid and AVAs accumulation in apricot fruit, which provide important targets for quality-oriented molecular breeding.
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Affiliation(s)
- Wanpeng Xi
- College of Food Science, Southwest University, Chongqing, China
- College of Horticulture and Landscape Architecture, Southwest University, Chongqing, China
| | - Lina Zhang
- College of Horticulture and Landscape Architecture, Southwest University, Chongqing, China
| | - Shengyu Liu
- College of Horticulture and Landscape Architecture, Southwest University, Chongqing, China
| | - Guohua Zhao
- College of Food Science, Southwest University, Chongqing, China
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Hricovíni M, Asher J, Hricovíni M. Photochemical anti- syn isomerization around the -N-N[double bond, length as m-dash] bond in heterocyclic imines. RSC Adv 2020; 10:5540-5550. [PMID: 35497446 PMCID: PMC9049245 DOI: 10.1039/c9ra10730d] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 01/28/2020] [Indexed: 11/21/2022] Open
Abstract
EPR and NMR experiments on a quinazolinone-based Schiff's base in DMSO solution showed that irradiation with UV light (365 nm) leads to photochemically-induced isomerization from the anti- to the higher-energy syn-form around the -N-N[double bond, length as m-dash] linkage. The anti- to syn-isomerization was relatively fast, and the maximum amount of conversion detected (25%) was reached within 10 min; thermodynamic equilibrium re-established itself in about 15 min. DFT calculations were performed on the investigated compound and small model systems, and reproduced the experimental fact of the anti-conformer being lower in energy than the syn. Theoretical analysis of excited states, including visualisation of natural transition orbitals, identified possible pathways for syn-anti isomerisation, although the details vary with π-system size, making the use of small models of limited utility. The investigated compound probably isomerises through the third singlet excited state (S3), a π-π* excitation, relaxing through S2, also a π-π* state.
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Affiliation(s)
- Michal Hricovíni
- Institute of Chemistry, Slovak Academy of Sciences Dúbravská cesta 9 845 38 Bratislava Slovak Republic
| | - James Asher
- Institute of Inorganic Chemistry, Slovak Academy of Sciences Dúbravská cesta 9 845 36 Bratislava Slovak Republic
| | - Miloš Hricovíni
- Institute of Chemistry, Slovak Academy of Sciences Dúbravská cesta 9 845 38 Bratislava Slovak Republic +421-2-5940222 +421-2-59410323
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Farfán-Paredes M, González-Antonio O, Tahuilan-Anguiano DE, Peón J, Ariza A, Lacroix PG, Santillan R, Farfán N. Physicochemical and computational insight of 19F NMR and emission properties of meso-(o-aryl)-BODIPYs. NEW J CHEM 2020. [DOI: 10.1039/d0nj02576c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Magnetic differentiation of the fluorine atoms was observed. The trends were explained in terms of their rotational energy barriers, group electronegativity and σ-Hammett.
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Affiliation(s)
- Mónica Farfán-Paredes
- Facultad de Química
- Departamento de Química Orgánica
- Universidad Nacional Autónoma de México
- Mexico
| | - Oscar González-Antonio
- Facultad de Química
- Departamento de Química Orgánica
- Universidad Nacional Autónoma de México
- Mexico
| | | | - Jorge Peón
- Instituto de Química
- Universidad Nacional Autónoma de México
- Mexico
| | - Armando Ariza
- Departamento de Química
- Centro de Investigación y de Estudios Avanzados del IPN
- México D.F. 07000
- Mexico
| | - Pascal G. Lacroix
- CNRS, Laboratoire de Chimie de Coordination (LCC)
- 205 route de Narbonne
- BP44099
- 31077 Toulouse Cedex 4
- France
| | - Rosa Santillan
- Departamento de Química
- Centro de Investigación y de Estudios Avanzados del IPN
- México D.F. 07000
- Mexico
| | - Norberto Farfán
- Facultad de Química
- Departamento de Química Orgánica
- Universidad Nacional Autónoma de México
- Mexico
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Penzkofer A, Silapetere A, Hegemann P. Photocycle Dynamics of the Archaerhodopsin 3 Based Fluorescent Voltage Sensor QuasAr1. Int J Mol Sci 2019; 21:ijms21010160. [PMID: 31881701 PMCID: PMC6982170 DOI: 10.3390/ijms21010160] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 12/18/2019] [Accepted: 12/19/2019] [Indexed: 11/16/2022] Open
Abstract
The retinal photocycle dynamics of the fluorescent voltage sensor QuasAr1 (Archaerhodopsin 3 P60S-T80S-D95H-D106H-F161V mutant from Halorubrum sodomense) in pH 8 Tris buffer was studied. The samples were photoexcited to the first absorption band of the protonated retinal Schiff base (PRSB) Ret_580 (absorption maximum at λmax ≈ 580 nm), and the retinal Schiff base photoisomerization and protonation state changes were followed by absorption spectra recordings during light exposure and after light exposure. Ret_580 turned out to be composed of two protonated retinal Schiff base isomers, namely Ret_580I and Ret_580II. Photoexcitation of Ret_580I resulted in barrier-involved isomerization to Ret_540 (quantum yield ≈ 0.056) and subsequent retinal proton release leading to Ret_410 deprotonated retinal Schiff base (RSB). In the dark, Ret_410 partially recovered to Ret_580I and partially stabilized to irreversible Ret_400 due to apoprotein restructuring (Ret_410 lifetime ≈ 2 h). Photoexcitation of Ret_580II resulted in barrier-involved isomerization to Ret_640 (quantum yield ≈ 0.00135) and subsequent deprotonation to Ret_370 (RSB). In the dark, Ret_370 partially recovered to Ret_580II and partially stabilized to irreversible Ret_350 due to apoprotein restructuring (Ret_370 lifetime ≈ 10 h). Photocycle schemes and reaction coordinate diagrams for Ret_580I and Ret_580II were developed and photocyle parameters were determined.
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Affiliation(s)
- Alfons Penzkofer
- Fakultät für Physik, Universität Regensburg, Universitätsstraße 31, D-93053 Regensburg, Germany
- Correspondence: ; Tel.: +49-941-943-2107
| | - Arita Silapetere
- Experimentelle Biophysik, Institut für Biologie, Humboldt Universität zu Berlin, Invalidenstraße 42, D-10115 Berlin, Germany; (A.S.); (P.H.)
| | - Peter Hegemann
- Experimentelle Biophysik, Institut für Biologie, Humboldt Universität zu Berlin, Invalidenstraße 42, D-10115 Berlin, Germany; (A.S.); (P.H.)
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Absorption and Emission Spectroscopic Investigation of Thermal Dynamics and Photo-Dynamics of the Rhodopsin Domain of the Rhodopsin-Guanylyl Cyclase from the Nematophagous Fungus Catenaria anguillulae. Int J Mol Sci 2017; 18:ijms18102099. [PMID: 28981475 PMCID: PMC5666781 DOI: 10.3390/ijms18102099] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 09/27/2017] [Accepted: 09/28/2017] [Indexed: 11/16/2022] Open
Abstract
The rhodopsin-guanylyl cyclase from the nematophagous fungus Catenaria anguillulae belongs to a recently discovered class of enzymerhodopsins and may find application as a tool in optogenetics. Here the rhodopsin domain CaRh of the rhodopsin-guanylyl cyclase from Catenaria anguillulae was studied by absorption and emission spectroscopic methods. The absorption cross-section spectrum and excitation wavelength dependent fluorescence quantum distributions of CaRh samples were determined (first absorption band in the green spectral region). The thermal stability of CaRh was studied by long-time attenuation measurements at room temperature (20.5 °C) and refrigerator temperature of 3.5 °C. The apparent melting temperature of CaRh was determined by stepwise sample heating up and cooling down (obtained apparent melting temperature: 62 ± 2 °C). The photocycle dynamics of CaRh was investigated by sample excitation to the first inhomogeneous absorption band of the CaRhda dark-adapted state around 590 nm (long-wavelength tail), 530 nm (central region) and 470 nm (short-wavelength tail) and following the absorption spectra development during exposure and after exposure (time resolution 0.0125 s). The original protonated retinal Schiff base PRSBall-trans in CaRhda photo-converted reversibly to protonated retinal Schiff base PRSBall-trans,la1 with restructured surroundings (CaRhla₁ light-adapted state, slightly blue-shifted and broadened first absorption band, recovery to CaRhda with time constant of 0.8 s) and deprotonated retinal Schiff base RSB13-cis (CaRhla₂ light-adapted state, first absorption band in violet to near ultraviolet spectral region, recovery to CaRhda with time constant of 0.35 s). Long-time light exposure of light-adapted CaRhla₁ around 590, 530 and 470 nm caused low-efficient irreversible degradation to photoproducts CaRhprod. Schemes of the primary photocycle dynamics of CaRhda and the secondary photocycle dynamics of CaRhla1 are developed.
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Srinivasan S, Cordomí A, Ramon E, Garriga P. Beyond spectral tuning: human cone visual pigments adopt different transient conformations for chromophore regeneration. Cell Mol Life Sci 2016; 73:1253-63. [PMID: 26387074 PMCID: PMC11108329 DOI: 10.1007/s00018-015-2043-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 09/09/2015] [Accepted: 09/10/2015] [Indexed: 01/01/2023]
Abstract
Human red and green visual pigments are seven transmembrane receptors of cone photoreceptor cells of the retina that mediate color vision. These pigments share a very high degree of homology and have been assumed to feature analogous structural and functional properties. We report on a different regeneration mechanism among red and green cone opsins with retinal analogs using UV-Vis/fluorescence spectroscopic analyses, molecular modeling and site-directed mutagenesis. We find that photoactivated green cone opsin adopts a transient conformation which regenerates via an unprotonated Schiff base linkage with its natural chromophore, whereas red cone opsin forms a typical protonated Schiff base. The chromophore regeneration kinetics is consistent with a secondary retinal uptake by the cone pigments. Overall, our findings reveal, for the first time, structural differences in the photoactivated conformation between red and green cone pigments that may be linked to their molecular evolution, and support the proposal of secondary retinal binding to visual pigments, in addition to binding to the canonical primary site, which may serve as a regulatory mechanism of dark adaptation in the phototransduction process.
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Affiliation(s)
- Sundaramoorthy Srinivasan
- Departament d'Enginyeria Química, Centre de Biotecnologia Molecular, Universitat Politècnica de Catalunya, Rambla de Sant Nebridi 22, 08222, Terrassa, Spain
| | - Arnau Cordomí
- Laboratori de Medicina Computacional, Unitat de Bioestadística, Facultat de Medicina, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, 08193, Barcelona, Spain
| | - Eva Ramon
- Departament d'Enginyeria Química, Centre de Biotecnologia Molecular, Universitat Politècnica de Catalunya, Rambla de Sant Nebridi 22, 08222, Terrassa, Spain
| | - Pere Garriga
- Departament d'Enginyeria Química, Centre de Biotecnologia Molecular, Universitat Politècnica de Catalunya, Rambla de Sant Nebridi 22, 08222, Terrassa, Spain.
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Kubli-Garfias C, Vázquez-Ramírez R, Cabrera-Vivas BM, Gómez-Reyes B, Ramírez JC. Atomic and molecular analysis highlights the biophysics of unprotonated and protonated retinal in UV and scotopic vision. Photochem Photobiol Sci 2015; 14:1660-72. [DOI: 10.1039/c5pp00091b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Unprotonated (UR) and protonated (PR) retinal have marked atomic and molecular differences in cis and trans configurations. In conclusion, UR and PR uphold UV and light vision through their different biophysical properties.
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Affiliation(s)
- Carlos Kubli-Garfias
- Instituto de Investigaciones Biomédicas
- Universidad Nacional Autónoma de México
- México
- Mexico
| | | | | | | | - Juan Carlos Ramírez
- Facultad de Ciencias Químicas
- Benemérita Universidad Autónoma de Puebla
- Puebla 72530
- Mexico
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Chiang HK, Chu LK. Solvent isotope effect on the dark adaptation of bacteriorhodopsin in purple membrane: viewpoints of kinetics and thermodynamics. J Phys Chem B 2014; 118:2662-9. [PMID: 24533671 DOI: 10.1021/jp412475u] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The thermal retinal isomerization from all-trans, 15-anti to 13-cis, 15-syn of bacteriorhodopsin in purple membrane in H2O and D2O during dark adaptation was investigated at 30-55 °C at neutral pH. In this temperature range, phase transition of purple membrane and destruction of the tertiary structure of bacteriorhodopsin did not take place. We found that the solvent isotope effect is inverted below about 45 °C; i.e., k(f)(D2O)/k(f)(H2O) > 1. Applying the transition state theory, the changes in enthalpy from the initial state to the transition state along the thermal trans-to-cis forward reaction coordinate, ΔH(f)*, were determined to be 24.7 ± 1.2 and 20.1 ± 0.4 kcal mol(-1) in H2O and D2O, respectively. The relative entropic change of the transition state in H2O and D2O, ΔΔS(f)* = ΔS(f)*(D2O) - ΔS(f)*(H2O), was -14.4 ± 3.9 cal mol(-1) K(-1). In addition, the Gibbs free energy of trans-to-cis thermal isomerization reaction in D2O is 0.4-0.7 kcal mol(-1) lower than that in H2O. It is the first time the entropy and enthalpy of the transition state have been quantified to elucidate the solvent isotope effect in the retinal thermal isomerization of bacteriorhodopsin during dark adaptation. The solvent isotope effect on the thermodynamics properties and kinetics implied that the hydrogen bonding in the transition state during the dark adaptation of bR is stronger than that in the initial state.
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Affiliation(s)
- Han-Kuei Chiang
- Department of Chemistry, National Tsing Hua University , 101, Sec. 2, Kuang-Fu Rd., Hsinchu 30013, Taiwan
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Fluorescent oligomers of dibenzothiophene-S,S-dioxide derivatives: the interplay of crystal conformations and photo-physical properties. Tetrahedron 2012. [DOI: 10.1016/j.tet.2012.04.085] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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