Encyclopedia of Biophysics

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

Nucleic Acid Circular Dichroism

  • Alison Rodger
Living reference work entry
DOI: https://doi.org/10.1007/978-3-642-35943-9_632-1

Synonyms

DNA

Definition

Deoxyribonucleic acid, DNA, is composed of planar aromatic nucleic acid bases linked to a sugar and a phosphate as illustrated in Fig. 1. Ribonucleic acid, RNA, differs from DNA by an extra oxygen on the sugar, and also thymine is replaced by uracil which does not have the methyl substituent. Most of the DNA and RNA transitions we measure with UV spectroscopy are due to the π–π* transitions of the bases. These transitions have no intrinsic CD signal since the bases are planar and hence achiral. However, the isolated nucleosides acquire asymmetry in their electronic transitions by coupling with the chiral ribose sugar units of the backbone. The magnitude of Δ ε max (the molar difference in absorbance of left and right circularly polarized light) for each base is of the order of 2 mol −1 dm 3 cm −1at 270 nm; the purine bases have a negative signal, whereas the pyrimidine ones have a positive CD in that region. When the bases are linked by phosphodiester bonds to form...
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References

  1. Arscott PG, Ma C, Wenner JR, Bloomfield VA (1995) DNA condensation by cobalt hexaammine(III) in alcohol-water mixtures: dielectric constant and other solvent effects. Biopolymers 36:345–365CrossRefPubMedGoogle Scholar
  2. Berova N, Polavarapu PL, Nakanishi K, Woody RW, editors (2014) Comprehensive chiroptical spectroscopy. Wiley-VCH, New YorkGoogle Scholar
  3. Nordén B, Rodger A, Dafforn TR (2010) Linear dichroism and circular dichroism: a textbook on polarized spectroscopy. Royal Society of Chemistry, CambridgeGoogle Scholar

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