Equipment

J-815 Circular Dichroism Spectropolarimeter

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Description

Computer controlled circular dichroism measurement system with Xe lamp (150W), cooled with air. Equipped with computer controlled temperature sample holder and magnetic stirring at different rpm. The cell holder is thermostated with a Peltier element. The system allows for temperature ramping (heating or cooling) while acquiring data at a fixed wavelength.
For more information please see link http://www.jascoinc.com/products/spectroscopy/circular-dichroism. Circular dichroism (CD) spectroscopy measures differences in the absorption of left-handed polarized light versus right-handed polarized light which arise due to structural asymmetry. The absence of regular structure results in zero CD intensity, while an ordered structure results in a spectrum which can contain both positive and negative signals.
Circular dichroism spectroscopy is particularly good for: a) determining whether a protein/DNA is folded, and if so characterizing its secondary structure, tertiary structure; b) comparing the structures of a protein obtained from different sources (e.g. species or expression systems) or comparing structures for different mutants of the same protein. The structural effects of single amino acid mutations in proteins can be detected with CD spectroscopy; c) studying the conformational stability of a protein under stress - thermal stability, pH stability, and stability to denaturants - and how this stability is altered by buffer composition or addition of stabilizers. CD is excellent for finding solvent conditions that increase the melting temperature and/or the reversibility of thermal unfolding; d) determining whether protein-protein or protein-ligand interactions alter the conformation of protein. If there are any conformational changes, this will result in a spectrum which will differ from the sum of the individual components. Small conformational changes have been seen, for example, upon formation of several different receptor/ligand complexes.

Available for external use

Associated technology

Optical polarimetry

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