The University of Massachusetts Amherst

Jasco J-1500 Circular Dichroism Spectrophotometer

Circular dichroism (CD) spectroscopy measures differences in the absorption of left-handed versus right-handed polarized light that result from structural asymmetry.

This measured difference gives important data regarding the structure and conformation of the molecule of interest. Any functional group that absorbs light will have a distinct CD signature within each absorption band, making CD spectroscopy useful in investigating the structures of small organic molecules, nucleic acids, higher-weight proteins, polymers, and polypeptides.

The secondary and tertiary structural components of the molecule of interest will impart a CD signature in the UV spectrum. This technique can provide an indication of the percentage of the molecule that is in each conformation (α-helix, β-sheet, β-turn, etc.), which can then be used in tandem with other techniques to deduce the complete structure. Using these principles, denaturation and other conformational changes, along with the thermodynamics of such changes, may also be studied.

  • Detection range: 163-950nm
  • Study conformational stability of a macromolecule under chemical and thermal stress
  • Determine whether molecular binding and other interactions alter the conformation of a protein
  • Negligible stray light (0.0003% at 200 nm) and noise (<0.01 mdeg at all wavelengths)
  • Rapid scan speed; can read across its full range in a few seconds
  • Attached Peltier unit for precise temperature control
  • Jasco's Spectra Manager suite integrates data acquisition, presentation, and low-level analysis, while the OLIS GlobalWorks software package is also available for detailed model-based analysis