Encyclopedia of Biophysics

Living Edition
| Editors: Gordon Roberts, Anthony Watts, European Biophysical Societies

DNA-Ligand Flow Linear Dichroism

  • Alison RodgerEmail author
Living reference work entry
DOI: https://doi.org/10.1007/978-3-642-35943-9_635-1



Linear dichroism (LD) is the difference in the absorption of light polarized parallel and perpendicular to an orientation direction. A signal therefore implies that a sample is oriented. DNA is a semirigid polymer which can be shear flow-oriented if it is more than ~450 base pairs in length. Anything bound to it is also oriented. If we know how the transition moments are oriented within a molecular coordinate framework, we can, from an observed linear dichroism (LD) spectrum, deduce something about how the molecules are aligned within the sample. Since small molecules cannot be flow-oriented, a simple and sometimes very useful application of LD is for detecting interactions between a small molecule and a biological macromolecule such as DNA that can be flow-oriented. Complete absence of a flow LD at the ligand transition wavelengths is generally a safe indication that the dye does not interact with DNA,...

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Copyright information

© European Biophysical Societies' Association (EBSA) 2018

Authors and Affiliations

  1. 1.Department of Molecular SciencesMacquarie UniversityMacquarie ParkAustralia

Section editors and affiliations

  • Alison Rodger
    • 1
  1. 1.Department of Molecular Sciences, Macquarie UniversityNWSAustralia