Mechanisms and energetics for N-glycosidic bond cleavage of protonated 2′-deoxyguanosine and guanosine
| العنوان: | Mechanisms and energetics for N-glycosidic bond cleavage of protonated 2′-deoxyguanosine and guanosine |
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| المؤلفون: | M. T. Rodgers, R. R. Wu, Yu Chen |
| المصدر: | Physical Chemistry Chemical Physics. 18:2968-2980 |
| بيانات النشر: | Royal Society of Chemistry (RSC), 2016. |
| سنة النشر: | 2016 |
| مصطلحات موضوعية: | chemistry.chemical_classification, Guanosine, 010405 organic chemistry, Stereochemistry, Guanine, Hydrolysis, Deoxyguanosine, General Physics and Astronomy, Glycosidic bond, Protonation, 010402 general chemistry, 01 natural sciences, Dissociation (chemistry), 0104 chemical sciences, chemistry.chemical_compound, SN1 reaction, chemistry, SN2 reaction, Glycosides, Protons, Physical and Theoretical Chemistry, Bond cleavage |
| الوصف: | Experimental and theoretical investigations suggest that hydrolysis of N-glycosidic bonds generally involves a concerted SN2 or a stepwise SN1 mechanism. While theoretical investigations have provided estimates for the intrinsic activation energies associated with N-glycosidic bond cleavage reactions, experimental measurements to validate the theoretical studies remain elusive. Here we report experimental investigations for N-glycosidic bond cleavage of the protonated guanine nucleosides, [dGuo+H](+) and [Guo+H](+), using threshold collision-induced dissociation (TCID) techniques. Two major dissociation pathways involving N-glycosidic bond cleavage, resulting in production of protonated guanine or the elimination of neutral guanine are observed in competition for both [dGuo+H](+) and [Guo+H](+). The detailed mechanistic pathways for the N-glycosidic bond cleavage reactions observed are mapped via electronic structure calculations. Excellent agreement between the measured and B3LYP calculated activation energies and reaction enthalpies for N-glycosidic bond cleavage of [dGuo+H](+) and [Guo+H](+) in the gas phase is found indicating that these dissociation pathways involve stepwise E1 mechanisms in analogy to the SN1 mechanisms that occur in the condensed phase. In contrast, MP2 is found to significantly overestimate the activation energies and slightly overestimate the reaction enthalpies. The 2'-hydroxyl substituent is found to stabilize the N-glycosidic bond such that [Guo+H](+) requires ∼25 kJ mol(-1) more than [dGuo+H](+) to activate the glycosidic bond. |
| تدمد: | 1463-9084 1463-9076 |
| DOI: | 10.1039/c5cp05738h |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::3518fa8c05dbf887faaebb28252ed12a https://doi.org/10.1039/c5cp05738h |
| رقم الانضمام: | edsair.doi.dedup.....3518fa8c05dbf887faaebb28252ed12a |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 14639084 14639076 |
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| DOI: | 10.1039/c5cp05738h |