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Influence of 2'-deoxy sugar moiety on excited-state protonation equilibrium of adenine and adenosine with acridine inside SDS micelles: a time-resolved study with quantum chemical calculations.
Chemphyschem. 2012 Feb; 13(2):525-34.C

Abstract

The protonation dynamics of the DNA base adenine (Ade) and its nucleoside 2'-deoxyadenosine (d-Ade) are investigated by monitoring the deprotonation kinetics of an N-heterocyclic DNA intercalator, acridine (Acr), in the confined environment of sodium dodecyl sulfate (SDS) micelles. Protonation of acridine (AcrH(+)) occurs at the hydrophilic interface and this species remains in dynamic equilibrium with its deprotonated counterpart (Acr) inside the hydrophobic core of SDS micelles. Quenching of the fluorescence of AcrH(+)* at 478 nm is observed after addition of Ade and d-Ade with Stern-Volmer constant (K(SV)) 298 and 75 M(-1), respectively, with a concomitant increment in Acr* at 425 nm. Time-resolved fluorescence studies reveal quenching in the lifetime of AcrH(+)*. The relative amplitude of AcrH(+)* decreases from 0.97 to 0.51 and 0.97 to 0.89 with equimolar addition of Ade and d-Ade, respectively. These observations are explained by excited-state proton transfer (ESPT) from AcrH(+)* to the bases. The reduced K(SV) value and negligible change in the relative amplitudes of AcrH(+)* with d-Ade infer that ESPT is hindered substantially by the presence of a 2'-deoxy sugar unit. Transient time-resolved absorption spectra of Acr reflect that Ade reduces the absorbance of (3)AcrH(+)*; however, d-Ade keeps it unaltered for more than a time delay of 2 μs. The optimized geometries calculated by quantum chemical methods reflect deprotonation of AcrH(+)* with protonation at the N1 position of Ade, while it remains protonated with d-Ade. The hindered ESPT between AcrH(+)* and d-Ade singles out the significance of the 2'-deoxy sugar moiety in controlling the deprotonation kinetics.

Authors+Show Affiliations

Chemical Sciences Division, Saha Institute of Nuclear Physics, Bidhannagar, Kolkata, India.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

22241850

Citation

Sarangi, Manas Kumar, et al. "Influence of 2'-deoxy Sugar Moiety On Excited-state Protonation Equilibrium of Adenine and Adenosine With Acridine Inside SDS Micelles: a Time-resolved Study With Quantum Chemical Calculations." Chemphyschem : a European Journal of Chemical Physics and Physical Chemistry, vol. 13, no. 2, 2012, pp. 525-34.
Sarangi MK, Bhattacharyya D, Basu S. Influence of 2'-deoxy sugar moiety on excited-state protonation equilibrium of adenine and adenosine with acridine inside SDS micelles: a time-resolved study with quantum chemical calculations. Chemphyschem. 2012;13(2):525-34.
Sarangi, M. K., Bhattacharyya, D., & Basu, S. (2012). Influence of 2'-deoxy sugar moiety on excited-state protonation equilibrium of adenine and adenosine with acridine inside SDS micelles: a time-resolved study with quantum chemical calculations. Chemphyschem : a European Journal of Chemical Physics and Physical Chemistry, 13(2), 525-34. https://doi.org/10.1002/cphc.201100763
Sarangi MK, Bhattacharyya D, Basu S. Influence of 2'-deoxy Sugar Moiety On Excited-state Protonation Equilibrium of Adenine and Adenosine With Acridine Inside SDS Micelles: a Time-resolved Study With Quantum Chemical Calculations. Chemphyschem. 2012;13(2):525-34. PubMed PMID: 22241850.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Influence of 2'-deoxy sugar moiety on excited-state protonation equilibrium of adenine and adenosine with acridine inside SDS micelles: a time-resolved study with quantum chemical calculations. AU - Sarangi,Manas Kumar, AU - Bhattacharyya,Dhananjay, AU - Basu,Samita, Y1 - 2012/01/13/ PY - 2011/09/29/received PY - 2012/1/14/entrez PY - 2012/1/14/pubmed PY - 2012/5/26/medline SP - 525 EP - 34 JF - Chemphyschem : a European journal of chemical physics and physical chemistry JO - Chemphyschem VL - 13 IS - 2 N2 - The protonation dynamics of the DNA base adenine (Ade) and its nucleoside 2'-deoxyadenosine (d-Ade) are investigated by monitoring the deprotonation kinetics of an N-heterocyclic DNA intercalator, acridine (Acr), in the confined environment of sodium dodecyl sulfate (SDS) micelles. Protonation of acridine (AcrH(+)) occurs at the hydrophilic interface and this species remains in dynamic equilibrium with its deprotonated counterpart (Acr) inside the hydrophobic core of SDS micelles. Quenching of the fluorescence of AcrH(+)* at 478 nm is observed after addition of Ade and d-Ade with Stern-Volmer constant (K(SV)) 298 and 75 M(-1), respectively, with a concomitant increment in Acr* at 425 nm. Time-resolved fluorescence studies reveal quenching in the lifetime of AcrH(+)*. The relative amplitude of AcrH(+)* decreases from 0.97 to 0.51 and 0.97 to 0.89 with equimolar addition of Ade and d-Ade, respectively. These observations are explained by excited-state proton transfer (ESPT) from AcrH(+)* to the bases. The reduced K(SV) value and negligible change in the relative amplitudes of AcrH(+)* with d-Ade infer that ESPT is hindered substantially by the presence of a 2'-deoxy sugar unit. Transient time-resolved absorption spectra of Acr reflect that Ade reduces the absorbance of (3)AcrH(+)*; however, d-Ade keeps it unaltered for more than a time delay of 2 μs. The optimized geometries calculated by quantum chemical methods reflect deprotonation of AcrH(+)* with protonation at the N1 position of Ade, while it remains protonated with d-Ade. The hindered ESPT between AcrH(+)* and d-Ade singles out the significance of the 2'-deoxy sugar moiety in controlling the deprotonation kinetics. SN - 1439-7641 UR - https://www.unboundmedicine.com/medline/citation/22241850/Influence_of_2'_deoxy_sugar_moiety_on_excited_state_protonation_equilibrium_of_adenine_and_adenosine_with_acridine_inside_SDS_micelles:_a_time_resolved_study_with_quantum_chemical_calculations_ L2 - https://doi.org/10.1002/cphc.201100763 DB - PRIME DP - Unbound Medicine ER -