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Das M, Gangopadhyay D, Hudecová J, Kessler J, Kapitán J, Bouř P. Monitoring Conformation and Protonation States of Glutathione by Raman Optical Activity and Molecular Dynamics. Chempluschem 2023; 88:e202300219. [PMID: 37283530 DOI: 10.1002/cplu.202300219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 06/07/2023] [Accepted: 06/07/2023] [Indexed: 06/08/2023]
Abstract
Glutathione (GSH) is a common antioxidant and its biological activity depends on the conformation and protonation state. We used molecular dynamics, Raman and Raman optical activity (ROA) spectroscopies to investigate GSH structural changes in a broad pH range. Factor analysis of the spectra provided protonation constants (2.05, 3.45, 8.62, 9.41) in good agreement with previously published values. Following the analysis, spectra of differently protonated forms were obtained by extrapolation. The complete deprotonation of the thiol group above pH 11 was clearly visible in the spectra; however, many spectral features did not change much with pH. Experimental spectra at various pH values were decomposed into the simulated ones, which allowed us to study the conformer populations and quality of molecular dynamics (MD). According to this combined ROA/MD analysis conformation of the GSH backbone is affected by the pH changes only in a limited way. The combination of ROA with the computations thus has the potential to improve the MD force field and obtain more accurate populations of the conformer species. The methodology can be used for any molecule, but for a more detailed insight better computational techniques are needed in the future.
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Affiliation(s)
- Moumita Das
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo náměstí 2, 16610, Prague 6, Czech Republic
- Department of Analytical Chemistry Faculty of Chemical Engineering, University of Chemistry and Technology, Technická 5, 16628, Prague 6, Czech Republic
| | - Debraj Gangopadhyay
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo náměstí 2, 16610, Prague 6, Czech Republic
| | - Jana Hudecová
- Department of Optics, Palacký University, 17. listopadu 12, 77146, Olomouc, Czech Republic
| | - Jiří Kessler
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo náměstí 2, 16610, Prague 6, Czech Republic
| | - Josef Kapitán
- Department of Optics, Palacký University, 17. listopadu 12, 77146, Olomouc, Czech Republic
| | - Petr Bouř
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo náměstí 2, 16610, Prague 6, Czech Republic
- Department of Analytical Chemistry Faculty of Chemical Engineering, University of Chemistry and Technology, Technická 5, 16628, Prague 6, Czech Republic
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Schrenková V, Para Kkadan MS, Kessler J, Kapitán J, Bouř P. Molecular dynamics and Raman optical activity spectra reveal nucleotide conformation ratios in solution. Phys Chem Chem Phys 2023; 25:8198-8208. [PMID: 36880812 DOI: 10.1039/d2cp05756e] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Nucleotide conformational flexibility affects their biological functions. Although the spectroscopy of Raman optical activity (ROA) is well suited to structural analyses in aqueous solutions, the link between the spectral shape and the nucleotide geometry is not fully understood. We recorded the Raman and ROA spectra of model nucleotides (rAMP, rGMP, rCMP, and dTMP) and interpreted them on the basis of molecular dynamics (MD) combined with density functional theory (DFT). The relation between the sugar puckering, base conformation and spectral intensities is discussed. Hydrogen bonds between the sugar's C3' hydroxyl and the phosphate groups were found to be important for the sugar puckering. The simulated spectra correlated well with the experimental data and provided an understanding of the dependence of the spectral shapes on conformational dynamics. Most of the strongest spectral bands could be assigned to vibrational molecular motions. Decomposition of the experimental spectra into calculated subspectra based on arbitrary maps of free energies provided experimental conformer populations, which could be used to verify and improve the MD predictions. The analyses indicate some flaws of common MD force fields, such as being unable to describe the fine conformer distribution. Also the accuracy of conformer populations obtained from the spectroscopic data depends on the simulations, improvement of which is desirable for gaining a more detailed insight in the future. Improvement of the spectroscopic and computational methodology for nucleotides also provides opportunities for its application to larger nucleic acids.
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Affiliation(s)
- Věra Schrenková
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences, Flemingovo náměstí 2, 16610 Prague, Czech Republic. .,Department of Analytical Chemistry, University of Chemistry and Technology, Technická 5, 16628 Prague, Czech Republic
| | - Mohammed Siddhique Para Kkadan
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences, Flemingovo náměstí 2, 16610 Prague, Czech Republic. .,Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, 121 16, Prague, Czech Republic
| | - Jiří Kessler
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences, Flemingovo náměstí 2, 16610 Prague, Czech Republic.
| | - Josef Kapitán
- Department of Optics, Palacký University Olomouc, 17. listopadu 12, 77146, Olomouc, Czech Republic
| | - Petr Bouř
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences, Flemingovo náměstí 2, 16610 Prague, Czech Republic. .,Department of Analytical Chemistry, University of Chemistry and Technology, Technická 5, 16628 Prague, Czech Republic
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Hudecová J, Kapitán J, Dračínský M, Michal P, Profant V, Bouř P. Structure of Zinc and Nickel Histidine Complexes in Solution Revealed by Molecular Dynamics and Raman Optical Activity. Chemistry 2022; 28:e202202045. [DOI: 10.1002/chem.202202045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Indexed: 11/08/2022]
Affiliation(s)
- Jana Hudecová
- Institute of Organic Chemistry and Biochemistry Academy of Sciences Flemingovo náměstí 2 16000 Prague Czech Republic
- Department of Optics Palacký University 17. listopadu 12 771 46 Olomouc Czech Republic
| | - Josef Kapitán
- Department of Optics Palacký University 17. listopadu 12 771 46 Olomouc Czech Republic
| | - Martin Dračínský
- Institute of Organic Chemistry and Biochemistry Academy of Sciences Flemingovo náměstí 2 16000 Prague Czech Republic
| | - Pavel Michal
- Department of Optics Palacký University 17. listopadu 12 771 46 Olomouc Czech Republic
| | - Václav Profant
- Faculty of Mathematics and Physics Charles University Ke Karlovu 5 121 16 Prague Czech Republic
| | - Petr Bouř
- Institute of Organic Chemistry and Biochemistry Academy of Sciences Flemingovo náměstí 2 16000 Prague Czech Republic
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Yamamoto S, Kimura F. Probing the solvation of the α-helix with extended amide III bands in Raman optical activity. Phys Chem Chem Phys 2022; 24:3191-3199. [PMID: 35043805 DOI: 10.1039/d1cp04480j] [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
Experimental and theoretical Raman optical activity (ROA) study of α-helical peptides and proteins has suggested that the relative intensity of two extended amide III ROA bands at ∼1340 cm-1 (I band) and ∼1300 cm-1 (II band) can be used to monitor the permittivity of the surrounding medium of the α-helix. So far, the ROA intensity ratio, II/III, has been interpreted from two different viewpoints. The first one is in terms of a direct effect of permittivity around the α-helix. The second one is based on a structural equilibrium of two types of α-helical structures, "hydrated" and "unhydrated" ones. In the present study, temperature- and solvent-dependences of II/III are measured for highly-α-helical peptides and compared to the theoretical spectra while varying the permittivity or the type of α-helical structure. A fragment method with partial optimization in the normal modes is adopted in density functional theory calculations. The main features of the experimental spectra and a trend of the observed II/III are well reproduced by the simulations, which leads us to a conclusion that the II/III is dominantly governed by a direct influence of the permittivity of the environment and just accessorily by the equilibrium of the two types of α-helices. The simulations also opposed the conventional assignments of the I and II bands to "hydrated" and "unhydrated" α-helical structures, respectively. In the case of α-helical proteins, solvent exposure of the α-helix may be monitored by the ROA ratio.
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Affiliation(s)
- Shigeki Yamamoto
- Department of Chemistry, Graduate School of Science, Osaka University, Osaka 560-0043, Japan.
| | - Fumiya Kimura
- Department of Chemistry, Graduate School of Science, Osaka University, Osaka 560-0043, Japan.
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Michal P, Kapitan J, Kessler J, Bour P. Low-frequency Raman Optical Activity Provides Insight into Structure of Chiral Liquids. Phys Chem Chem Phys 2022; 24:19722-19733. [DOI: 10.1039/d2cp02290g] [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
Vibrational frequencies of modes involving intermolecular motions in liquids are relatively small, in the Raman scattering close to the excitation frequency, and the bands may merge into a diverging uninterpretable...
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