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Frere GA, Hasabnis A, Francisco CB, Suleiman M, Alimowska O, Rahmatullah R, Gould J, Su CYC, Voznyy O, Gunning PT, Basso EA, Prosser RS. Next-Generation Tags for Fluorine Nuclear Magnetic Resonance: Designing Amplification of Chemical Shift Sensitivity. J Am Chem Soc 2024; 146:3052-3064. [PMID: 38279916 DOI: 10.1021/jacs.3c09730] [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: 01/29/2024]
Abstract
Fluorine NMR is a highly sensitive technique for delineating the conformational states of biomolecules and has shown great utility in drug screening and in understanding protein function. Current fluorinated protein tags leverage the intrinsic chemical shift sensitivity of the 19F nucleus to detect subtle changes in protein conformation and topology. This chemical shift sensitivity can be amplified by embedding the fluorine or trifluoromethyl reporter within a pyridone. Due to their polarizability and rapid tautomerization, pyridones exhibit a greater range of electron delocalization and correspondingly greater 19F NMR chemical shift dispersion. To assess the chemical shift sensitivity of these tautomeric probes to the local environment, 19F NMR spectra of all possible monofluorinated and trifluoromethyl-tagged versions of 2-pyridone were recorded in methanol/water mixtures ranging from 100% methanol to 100% water. 4-Fluoro-2-pyridone and 6-(trifluoromethyl)-2-pyridone (6-TFP) displayed the greatest sensitivity of the monofluorinated and trifluoromethylated pyridones, exceeding that of known conventional CF3 reporters. To evaluate the utility of tautomeric pyridone tags for 19F NMR of biomolecules, the alpha subunit of the stimulatory G protein (Gsα) and human serum albumin (HSA) were each labeled with a thiol-reactive derivative of 6-TFP and the spectra were recorded as a function of various adjuvants and drugs. The tautomeric tag outperformed the conventional tag, 2-bromo-N-(4-(trifluoromethyl)phenyl)acetamide through the improved resolution of several functional states.
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Affiliation(s)
- Geordon A Frere
- Department of Chemistry, University of Toronto, CPS, UTM, 3359 Mississauga Rd, Mississauga, ON L5L 1C6, Canada
| | - Advait Hasabnis
- Department of Chemistry, University of Toronto, CPS, UTM, 3359 Mississauga Rd, Mississauga, ON L5L 1C6, Canada
| | - Camila B Francisco
- Department of Chemistry, University of Toronto, CPS, UTM, 3359 Mississauga Rd, Mississauga, ON L5L 1C6, Canada
- Department of Chemistry, State University of Maringá, 5790, Maringá 87020-900, Brazil
| | - Motasem Suleiman
- Department of Chemistry, University of Toronto, CPS, UTM, 3359 Mississauga Rd, Mississauga, ON L5L 1C6, Canada
| | - Olga Alimowska
- Department of Chemistry, University of Toronto, CPS, UTM, 3359 Mississauga Rd, Mississauga, ON L5L 1C6, Canada
| | - Rima Rahmatullah
- Department of Chemistry, University of Toronto, CPS, UTM, 3359 Mississauga Rd, Mississauga, ON L5L 1C6, Canada
| | - Jerome Gould
- Department of Chemistry, University of Toronto, CPS, UTM, 3359 Mississauga Rd, Mississauga, ON L5L 1C6, Canada
| | - Celia Yi-Chia Su
- Department of Chemistry, University of Toronto, CPS, UTM, 3359 Mississauga Rd, Mississauga, ON L5L 1C6, Canada
| | - Oleksandr Voznyy
- Department of Chemistry, University of Toronto, CPS, UTM, 3359 Mississauga Rd, Mississauga, ON L5L 1C6, Canada
| | - Patrick T Gunning
- Department of Chemistry, University of Toronto, CPS, UTM, 3359 Mississauga Rd, Mississauga, ON L5L 1C6, Canada
| | - Ernani A Basso
- Department of Chemistry, State University of Maringá, 5790, Maringá 87020-900, Brazil
| | - Robert S Prosser
- Department of Chemistry, University of Toronto, CPS, UTM, 3359 Mississauga Rd, Mississauga, ON L5L 1C6, Canada
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Głębocka A, Raczyńska ED, Chylewska A, Makowski M. Experimental (FT-IR) and theoretical (DFT) studies on prototropy and H-bond formation for pyrazine-2-amidoxime. J PHYS ORG CHEM 2016. [DOI: 10.1002/poc.3538] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Angelika Głębocka
- Laboratory of Intermolecular Interactions, Faculty of Chemistry; University of Gdańsk; Wita Stwosza 63 80-308 Gdańsk Poland
| | - Ewa D. Raczyńska
- Department of Chemistry; Warsaw University of Life Sciences; Nowoursynowska 159c 02-776 Warszawa Poland
| | - Agnieszka Chylewska
- Laboratory of Intermolecular Interactions, Faculty of Chemistry; University of Gdańsk; Wita Stwosza 63 80-308 Gdańsk Poland
| | - Mariusz Makowski
- Laboratory of Intermolecular Interactions, Faculty of Chemistry; University of Gdańsk; Wita Stwosza 63 80-308 Gdańsk Poland
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Abstract
Heterocyclic nucleic acid bases and their analogs can adopt multiple tautomeric forms due to the presence of multiple solvent-exchangeable protons. In DNA, spontaneous formation of minor tautomers has been speculated to contribute to mutagenic mispairings during DNA replication, whereas in RNA, minor tautomeric forms have been proposed to enhance the structural and functional diversity of RNA enzymes and aptamers. This review summarizes the role of tautomerism in RNA biochemistry, specifically focusing on the role of tautomerism in catalysis of small self-cleaving ribozymes and recognition of ligand analogs by riboswitches. Considering that the presence of multiple tautomers of nucleic acid bases is a rare occurrence, and that tautomers typically interconvert on a fast time scale, methods for studying rapid tautomerism in the context of nucleic acids under biologically relevant aqueous conditions are also discussed.
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Affiliation(s)
- Vipender Singh
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Bogdan I Fedeles
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - John M Essigmann
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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Direct observation of ground-state lactam-lactim tautomerization using temperature-jump transient 2D IR spectroscopy. Proc Natl Acad Sci U S A 2013; 110:9243-8. [PMID: 23690588 DOI: 10.1073/pnas.1303235110] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We provide a systematic characterization of the nanosecond ground-state lactam-lactim tautomerization of pyridone derivatives in aqueous solution under ambient conditions using temperature-jump transient 2D IR spectroscopy. Although electronic excited-state tautomerization has been widely studied, experimental work on the ground electronic state, most relevant to chemistry and biology, is lacking. Using 2D IR spectroscopy, lactam and lactim tautomers of 6-chloro-2-pyridone and 2-chloro-4-pyridone are unambiguously identified by their unique cross-peak patterns. Monitoring the correlated exponential relaxation of these signals in response to a laser temperature jump provides a direct measurement of the nanosecond tautomerization kinetics. By studying the temperature, concentration, solvent, and pH dependence, we extract a thermodynamic and kinetic characterization and conclude that the tautomerization proceeds through a two-state concerted mechanism. We find that the intramolecular proton transfer is mediated by bridging water molecules and the reaction barrier is dictated by the release of a proton from pyridone, as would be expected for an efficient Grothuss-type proton transfer mechanism.
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The influence of secondary interactions on complex stability and double proton transfer reaction in 2-[1H]-pyridone/2-hydroxypyridine dimers. J Mol Model 2010; 17:2491-500. [PMID: 21193938 DOI: 10.1007/s00894-010-0934-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Accepted: 12/09/2010] [Indexed: 10/18/2022]
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6
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Vána J, Sedlák M, Hanusek J. Kinetic Evidence for the Coexistence of Zwitterionic (T±), Neutral (T0) and Anionic (T−) Intermediates during Rearrangement of S-(2-Oxotetrahydrofuran-3-yl)-N-(4-methoxyphenyl)isothiuronium Bromide to 5-(2-Hydroxyethyl)-2-(4-methoxyphenylimino)-1,3-thiazolidin-4-one. J Org Chem 2010; 75:3729-36. [DOI: 10.1021/jo1004873] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jirí Vána
- Faculty of Chemical Technology, Institute of Organic Chemistry and Technology, University of Pardubice, CZ-532 10 Pardubice, The Czech Republic
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Sonnenberg JL, Wong KF, Voth GA, Schlegel HB. Distributed Gaussian Valence Bond Surface Derived from Ab Initio Calculations. J Chem Theory Comput 2009; 5:949-61. [DOI: 10.1021/ct800477y] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Jason L. Sonnenberg
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, and Department of Chemistry, University of Utah, Salt Lake City, Utah 84112
| | - Kim F. Wong
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, and Department of Chemistry, University of Utah, Salt Lake City, Utah 84112
| | - Gregory A. Voth
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, and Department of Chemistry, University of Utah, Salt Lake City, Utah 84112
| | - H. Bernhard Schlegel
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, and Department of Chemistry, University of Utah, Salt Lake City, Utah 84112
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Freeman F, Po HN, Ho TS, Wang X. Electrochemical Oxidation of 2-Pyrimidinethiols and Theoretical Study of Their Dimers, Disulfides, Sulfenyl Radicals, and Tautomers. J Phys Chem A 2008; 112:1643-55. [DOI: 10.1021/jp076545y] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Fillmore Freeman
- Department of Chemistry, University of California, Irvine, Irvine, California 92697-2025
| | - Henry N. Po
- Department of Chemistry and Biochemistry, California State University, Long Beach, Long Beach, California 90840
| | - Thach S. Ho
- Department of Chemistry and Biochemistry, California State University, Long Beach, Long Beach, California 90840
| | - Ximeng Wang
- Department of Chemistry and Biochemistry, California State University, Long Beach, Long Beach, California 90840
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Li QS, Fang WH, Yu JG. Theoretical studies of proton-transfer reactions of 2-hydroxypyridine--(H2O)n (n = 0-2) in the ground and excited states. J Phys Chem A 2007; 109:3983-90. [PMID: 16833720 DOI: 10.1021/jp044498t] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The potential energy profiles for proton-transfer reactions of 2-hydroxypyridine and its complexes with water were determined by MP2, CASSCF and MR-CI calculations with the 6-31G** basis set. The tautomerization reaction between 2-hydroxypyridine (2HP) and 2-pyridone (2PY) does not take place at room temperature because of a barrier of approximately 35 kcal/mol for the ground-state pathway. The water-catalyzed enol-keto tautomerization reactions in the ground state proceed easily through the concerted proton transfer, especially for the two-water complex. The S1 tautomerization between the 2HP and 2PY monomers has a barrier of 18.4 kcal/mol, which is reduced to 5.6 kcal/mol for the one-water complex and 6.4 kcal/mol for the two-water complex. The results reported here predict that the photoinduced tautomerization reaction between the enol and keto forms involves a cyclic transition state having one or two water molecules as a bridge.
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Affiliation(s)
- Quan-Song Li
- Department of Chemistry, Beijing Normal University, Beijing 100875, PR China
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Tsuchida N, Yamabe S. Reaction paths of tautomerization between hydroxypyridines and pyridones. J Phys Chem A 2007; 109:1974-80. [PMID: 16833531 DOI: 10.1021/jp040451w] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Tautomerization paths of 2(and 4)-hydroxypyridine (called here HP) to 2(and 4)-pyridone (called here PY) with water molecules were investigated by the use of density functional theory calculations. Potential energies were compared for a number of water molecules. The 2-HP molecule was found to be isomerized most readily and concertedly to the 2-PY one via proton relays with two water molecules. The reaction pattern is invariant even when outer water molecules are added. The 4-HP(H(2)O)(n) --> 4-PY(H(2)O)(n) reaction model did not give small activation energies. However, a reaction of (4-HP)(2)(H(2)O)(2) --> (4-PY)(2)(H(2)O)(2) was found to occur readily through a transient ion-pair intermediate. The conversion processes of (2-PY)(2) to the tautomerization reacting system were discussed. The hydrogen-bond directionality regulates the tautomerization paths.
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Affiliation(s)
- Noriko Tsuchida
- Department of Chemistry, Nara University of Education, Takabatake-cho, Nara 630-8528, Japan
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11
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Março PH, Scarminio IS. Q-mode curve resolution of UV–vis spectra for structural transformation studies of anthocyanins in acidic solutions. Anal Chim Acta 2007; 583:138-46. [PMID: 17386538 DOI: 10.1016/j.aca.2006.09.057] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2006] [Revised: 09/29/2006] [Accepted: 09/29/2006] [Indexed: 10/24/2022]
Abstract
Chemometric analysis of ultraviolet-visible (UV-vis) spectra for pH values 1.0, 3.3, 5.3, and 6.9 was used to investigate the kinetics and the structural transformations of anthocyanins in extracts of calyces of hibiscus flowers of the Hibiscus acetosella Welw. ex Finicius for the first time. Six different species were detected: the quinoidal base (A), the flavylium cation (AH+), the pseudobase or carbinol pseudobase (B), cis-chalcone (C(C)), trans-chalcone (C(t)), and ionized cis-chalcone (C(C)-). Four equilibrium constant values were calculated using relative concentrations, hydration, pK(h) = 2.60 +/- 0.01, tautomeric, K(T) = 0.14 +/- 0.01, acid-base, pK(a) = 4.24 +/- 0.04, and ionization of the cis-chalcone, pK(C(C)) = 8.74 +/- 1.5 x 10(-2). The calculated protonation rate of the tautomers is K(H+) = 0.08 +/- 7.6 x 10(-3). These constants are in excellent agreement with those measured previously in salt form. From a kinetic viewpoint, the situation encountered is interesting since the reported investigation is limited to visible light absorption in acid medium. These models have not been reported in the literature.
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Affiliation(s)
- Paulo Henrique Março
- Laboratório de Quimiometria em Ciências Naturais, Departamento de Química, Universidade Estadual de Londrina, Caixa Postal 6001, CEP 86051-970 Londrina, Paraná, Brazil
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12
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Stanovnik B, Tišler M, Katritzky AR, Denisko OV. The Tautomerism of Heterocycles: Substituent Tautomerism of Six-Membered Ring Heterocycles. ADVANCES IN HETEROCYCLIC CHEMISTRY 2006. [DOI: 10.1016/s0065-2725(06)91001-0] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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13
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Penedo JC, Rodríguez MCR, Lema IG, Lustres JLP, Mosquera M, Rodríguez-Prieto F. Two competitive routes in the lactim-lactam phototautomerization of a hydroxypyridine derivative cation in water: dissociative mechanism versus water-assisted proton transfer. J Phys Chem A 2005; 109:10189-98. [PMID: 16833311 DOI: 10.1021/jp0518355] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Ground-state tautomerism and excited-state proton-transfer processes of 2-(6'-hydroxy-2'-pyridyl)benzimidazolium in H2O and D2O have been studied by means of UV-vis absorption and fluorescence spectroscopy in both steady-state and time-resolved modes. In the ground state, this compound shows a tautomeric equilibrium between the lactim cation, protonated at the benzimidazole N3, and its lactam tautomer, obtained by proton translocation from the hydroxyl group to the pyridine nitrogen. Direct excitation of the lactam tautomer leads to its own fluorescence emission, while as a result of the increase of acidity of the OH group and basicity at the pyridine N upon excitation, the lactim species undergoes a proton translocation from the hydroxyl group to the nitrogen, favoring the lactam structure in the excited state. No fluorescence emission from the initially excited lactim species was detected due to the ultrafast rate of the excited-state proton-transfer processes. The lactim-lactam phototaumerization process takes place via two competitive excited-state proton-transfer routes: a one-step water-assisted proton translocation (probably a double proton transfer) and a two-step pathway which involves first the dissociation of the lactim cation to form an emissive intermediate zwitterionic species and then the acid-catalyzed protonation at the pyridine nitrogen to give rise to the lactam tautomer.
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Affiliation(s)
- J Carlos Penedo
- Departamento de Química Física, Facultade de Química, Universidade de Santiago de Compostela, E-15782 Santiago de Compostela, Spain
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Nien Schuchmann M, Naumov S, Schuchmann HP, von Sonntag J, von Sonntag C. 4-Amino-3H-pyrimidin-2-one (“isocytosine”) is a short-lived non-radical intermediate formed in the pulse radiolysis of cytosine in aqueous solution. Radiat Phys Chem Oxf Engl 1993 2005. [DOI: 10.1016/j.radphyschem.2003.12.058] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
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Kuzmin YI, Da Costa CP, Fedor MJ. Role of an active site guanine in hairpin ribozyme catalysis probed by exogenous nucleobase rescue. J Mol Biol 2004; 340:233-51. [PMID: 15201049 DOI: 10.1016/j.jmb.2004.04.067] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2004] [Revised: 04/23/2004] [Accepted: 04/23/2004] [Indexed: 11/18/2022]
Abstract
The hairpin ribozyme is a small catalytic RNA with reversible phosphodiester cleavage activity. Biochemical and structural studies exclude a requirement for divalent metal cation cofactors and implicate one active site nucleobase in particular, G8, in the catalytic mechanism. Our previous work demonstrated that the cleavage activity that is lost when G8 is replaced by an abasic residue is restored when certain nucleobases are provided in solution. The specificity and pH dependence of exogenous nucleobase rescue were consistent with several models of the rescue mechanism, including general acid base catalysis, electrostatic stabilization of negative charge in the transition state or a requirement for protonation to facilitate exogenous nucleobase binding. Detailed analyses of exogenous nucleobase rescue for both cleavage and ligation reactions now allow us to refine models of the rescue mechanism. Activity increased with increasing pH for both unmodified ribozyme reactions and unrescued reactions of abasic variants lacking G8. This similarity in pH dependence argues against a role for G8 as a general base catalyst, because G8 deprotonation could not be responsible for the pH-dependent transition in the abasic variant. Exogenous nucleobase rescue of both cleavage and ligation activity increased with decreasing pH, arguing against a role for rescuing nucleobases in general acid catalysis, because a nucleobase that contributes general acid catalysis in the cleavage pathway should provide general base catalysis in ligation. Analysis of the concentration dependence of cytosine rescue at high and low pH demonstrated that protonation promotes catalysis within the nucleobase-bound ribozyme complex but does not stabilize nucleobase binding in the ground state. These results support an electrostatic stabilization mechanism in which exogenous nucleobase binding counters negative charge that develops in the transition state.
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Affiliation(s)
- Yaroslav I Kuzmin
- Department of Molecular Biology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, MB35, La Jolla, CA 92037, USA
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Abdulla HI, El-Bermani MF. Infrared studies of tautomerism in 2-hydroxypyridine 2-thiopyridine and 2-aminopyridine. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2001; 57:2659-2671. [PMID: 11765793 DOI: 10.1016/s1386-1425(01)00455-3] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The infrared spectra of 2-hydroxypyridine (2-OHP), 2-thiopyridine (2-SHP), and 2-aminopyridine (2-NH2P) have been recorded in the solid, liquid and vapor phases in the region 4000-200 cm(-1). To support the work, deuterated forms of these compounds in the functional groups XH and NH with (X=O, S, NH) were recorded for the solid and liquid phases. The results show existence of each compound as an equilibrium mixture of two tautomers in monomeric and cyclic dimeric forms in the solid, liquid and vapor phases. The monomers are predominant in the vapor phase. Enthalpy differences between the monomeric tautomers and activation energies for their inter-conversion were determined in each phase.
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Affiliation(s)
- H I Abdulla
- Department of Chemistry, College of Science, University of Baghdad, Iraq
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Matsuda Y, Ebata T, Mikami N. IR−UV Double-Resonance Spectroscopic Study of 2-Hydroxypyridine and Its Hydrogen-Bonded Clusters in Supersonic Jets. J Phys Chem A 2001. [DOI: 10.1021/jp003272x] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Yoshiyuki Matsuda
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Takayuki Ebata
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Naohiko Mikami
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
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18
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Matsuda Y, Ebata T, Mikami N. Population labeling spectroscopy for the electronic and the vibrational transitions of 2-pyridone and its hydrogen-bonded clusters. J Chem Phys 2000. [DOI: 10.1063/1.481833] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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19
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Matsuda Y, Ebata T, Mikami N. Vibrational spectroscopy of 2-pyridone and its clusters in supersonic jets: Structures of the clusters as revealed by characteristic shifts of the NH and C=O bands. J Chem Phys 1999. [DOI: 10.1063/1.478748] [Citation(s) in RCA: 141] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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21
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Dynamic NMR Spectroscopy in the Presence of Kinetic Hydrogen/Deuterium Isotope Effects. DEUTERIUM AND SHIFT CALCULATION 1990. [DOI: 10.1007/978-3-642-75932-1_2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Moriya T. Excited-State Reactions of Coumarins. VII. The Solvent-Dependent Fluorescence of 7-Hydroxycoumarins. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1988. [DOI: 10.1246/bcsj.61.1873] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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23
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Moriya T. Excited-State Reactions of Coumarins in Aqueous Solutions. VI. Fluorescence Quenching of 7-Hydroxycoumarins by Chloride Ions in Acidic Solutions. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1988. [DOI: 10.1246/bcsj.61.753] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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24
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Pogonin VI, Petrova TV, Pugachev VL, Chibisov AK. Kinetics of the tautomeric conversions of monoazo-substituted chromotropic acids in solution. Russ Chem Bull 1986. [DOI: 10.1007/bf00953212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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25
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Hibbert F. Mechanisms of Proton Transfer between Oxygen and Nitrogen Acids and Bases in Aqueous Solution. ADVANCES IN PHYSICAL ORGANIC CHEMISTRY 1986. [DOI: 10.1016/s0065-3160(08)60168-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Kuzuya M, Noguchi A, Okuda T. Quantum Chemical Consideration of Substituent Effects on Tautomeric Properties of 2-Pyridones–2-Pyridinols. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1984. [DOI: 10.1246/bcsj.57.3454] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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29
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Moriya T. Excited-state Reactions of Coumarins in Aqueous Solutions. I. The Phototautomerization of 7-Hydroxycoumarin and Its Derivative. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1983. [DOI: 10.1246/bcsj.56.6] [Citation(s) in RCA: 73] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Jordan F, Chen G, Nishikawa S, Wu BS. Potential roles of the aminopyrimidine ring in thiamin catalyzed reactions. Ann N Y Acad Sci 1982; 378:14-31. [PMID: 6282162 DOI: 10.1111/j.1749-6632.1982.tb31183.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
|
32
|
|
33
|
SEQUENTIAL FAST KINETICS BY RELAXATION: APPLICATION IN CHEMISTRY AND BIOCHEMISTRY. Anal Chem 1979. [DOI: 10.1016/b978-0-08-022037-6.50005-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
34
|
|
35
|
Bensaude O, Chevrier M, Dubois JE. Equilibre tautomere du phenyl-methyl-pyrazole en solution aqueuse: mecanisme de l'interconversion. Tetrahedron 1978. [DOI: 10.1016/0040-4020(78)89036-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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