N-H stretching excitations in adenosine-thymidine base pairs in solution: pair geometries, infrared line shapes, and ultrafast vibrational dynamics.

ABSTRACT: We explore the N-H stretching vibrations of adenosine-thymidine base pairs in chloroform solution with linear and nonlinear infrared spectroscopy. Based on estimates from NMR measurements and ab initio calculations, we conclude that adenosine and thymidine form hydrogen bonded base pairs in Watson-Crick, reverse Watson-Crick, Hoogsteen, and reverse Hoogsteen configurations with similar probability. Steady-state concentration and temperature dependent linear FT-IR studies, including H/D exchange experiments, reveal that these hydrogen-bonded base pairs have complex N-H/N-D stretching spectra with a multitude of spectral components. Nonlinear 2D-IR spectroscopic results, together with IR-pump-IR-probe measurements, as also corroborated by ab initio calculations, reveal that the number of N-H

SUBMITTER: Greve C 

PROVIDER: S-EPMC3578714 | biostudies-literature | 2013 Jan

REPOSITORIES: biostudies-literature