Structure and Dynamics of DNA and DNA-Adduct Complexes Studied with Polarized Light Spectroscopy
Optical methods provide useful complements to NMR and other physical methods in the study of biomolecular structure in solution. Techniques utilizing polarized light, i.e. linear dichroism (LD), circular dichroism (CD) and fluorescence polarization anisotropy (FPA) are especially attractive since macromolecular conformation and mobility can be deduced via intrinsic transition moment directions. For the nucleic acid bases, the directions of the active UV transitions and the shapes of their absorption components have been determined from measurements in oriented matrices in which crystal interactions are minimized. The conformation of the base pairs in various DNA forms, and the three-dimensional structure of several DNA-drug complexes have been obtained using the flow-LD technique.1–3 Additional, independent, information is available from the CD induced in electric-dipole allowed transitions of DNA adducts owing to interactions with chirally disposed DNA base transitions.4 Information about anisotropic mobility is contained m the excitation polarization spectrum of fluorescent dyes,5 which has been used to characterize anisotropic DNA motions.6
KeywordsGlycerol Anisotropy Bromide Adduct Ethidium
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- 6.Härd, T. and Kearns, D.R. submitted papers.Google Scholar