Nucleic Acid Linear Dichroism

Abstract

Synonyms Anisotropic spectroscopy; DNA

Definition A linear dichroism (LD) spectrum shows the difference in absorbance of light polarized parallel and perpendicular to an orientation direction (Rodger and Nordén 1997; Nordén et al 2010). The idealized structure of B-DNA has the base pairs oriented perpendicular to the DNA helix axis to a first approximation. This means the π–π* transitions take place in the plane perpendicular to the helix axis, and so these are expected to give a negative LD signal as illustrated in Fig. 1. LD can be used to probe changes in orientation of the DNA bases. Show more