Encyclopedia of Biophysics

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

Absorption Spectroscopy to Probe Ligand Binding

  • Alison Rodger
Living reference work entry
DOI: https://doi.org/10.1007/978-3-642-35943-9_778-1

Synonyms

Definition

When a ligand solution is added to a solution of biomacromolecules, if it does not bind to the macromolecules, then the UV–visible spectrum will simply be the sum of the macromolecule spectrum and the ligand spectrum. If the ligand does bind to the macromolecules, then the spectrum of the complex will be (at least slightly) different from the sum spectrum. One should note that the observed spectrum is probably a complicated mixture of the spectrum of bound and unbound ligands and free and complexed macromolecules.

Sometimes there are changes in the spectrum characteristic of the type of interaction. For example, when two planar aromatic molecules bind together, such as an aromatic ligand intercalating between two DNA base pairs, there is usually a characteristic decrease in the ligand-absorbance signal (hypochromism) of up to 50% and a shift to longer wavelength (bathochromic shift) of between ∼2 and 20nm as...
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References

  1. Pyle AM, Rehmann JP, Meshoyrer R, Kumar CV, Turro NJ, Barton JK (1989) Mixed-ligand complexes of ruthenium(II): factors governing binding to DNA. J Am Chem Soc 111:3051–3058CrossRefGoogle Scholar
  2. Scatchard G (1949) The attractions of proteins for small molecules and ions. Ann NY Acad Sci 51:660–672CrossRefGoogle Scholar
  3. Schmechel DEV, Crothers DMB (1971) Kinetic and hydrodynamic studies of the complex of proflavine with poly A·poly U. Biolopymers 10:465–480Google Scholar
  4. Tan WB, Bhambhani A, Duff MR, Rodger A, Kumar CV (2006) Spectroscopic identification of binding modes of anthracene probes and DNA sequence recognition. Photochem Photobiol 82:20–30CrossRefPubMedGoogle Scholar

Copyright information

© European Biophysical Societies' Association (EBSA) 2018

Authors and Affiliations

  1. 1.Department of Molecular SciencesMacquarie UniversitySydneyAustralia

Section editors and affiliations

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