Circular Dichroism (CD) Instrumentation

Jasco J-715 Spectropolarimeter

This is a walk-up instrument or samples can be dropped off to be run for an additional fee. Training on the instrument is also available. Scheduling of this instrument is done through the Faces Scheduling System. See the Calendars and Scheduling page for more information. Visit the Research Store for current pricing.

CD spectroscopy measures the difference in absorbtion of left and right handed circularly polarized light. In general, the CD phenomenon will occur for any optically active molecule. Importantly the CD signal for proteins and DNA is imparted by the secondary structure, which has chirality. Thus CD is a good technique to measure the secondary structure in proteins.

In particular CD is good for:

  • Determining if a protein is folded
  • Determining the percent helix, sheet, turns, and random structure in proteins
  • Comparing the secondary structure of proteins in different conditions such as temperature, pH, ionic strength, ligands, etc.
  • Measuring protein stability through thermal melts and denaturation studies
  • Testing the structural integrity of mutants

Typical protein concentrations for CD are 0.1 to 0.3 mg/ml when using a 0.1 mm path length cell and a volume of 225 ul. See the CD Instruction Manual for detailed instructions on using the instrument along with information about sample preparation and analysis.

Jasco J-715 spectropolarimeter