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Circular Dichroism Services
Chiralabs are leading experts in circular dichroism and chiroptical spectroscopy. We have one of the world's most extensive chiroptical spectroscopy facilities, including Circular Dichroism (CD Spectroscopy), variable temperature Circular Dichroism, microsample Circular Dichroism, Cryo-Circular Dichroism, Fluorescence Detected Circular Dichroism (FD-CD), Magnetic Circular Dichroism (MCD), Optical Rotatory Dispersion (ORD) and High-Sensitivity Polarimetry. Our five CD spectrometers have each been specially adapted in-house for enhanced performance with challenging samples and high-precision comparability studies, backed up by a suite of other spectroscopies and techniques. Our spectroscopy laboratory, analytical laboratory and chromatography laboratory have extensive instrumentation and experience in combining CD spectroscopy in multi-technique investigations.
Chiralabs offers a contract circular dichroism service that can provide from just a "one-off" study through to a comprehensive service on a call-off, contract or project basis all supported by our expert scientists. Chiralabs undertakes circular dichroism studies on molecules ranging from small chiral drugs and transition metal complexes through to biomacromolecular structures such as proteins, glycoproteins and nucleic acids.
In particular, we have developed unique algorithms for determining the secondary structure of proteins in more detail and to greater reliability than that generally available elsewhere. We have also developed objective methods for comparing spectra, as used in unbiased comparability studies of biopharmaceuticals and biosimilars for development, production monitoring and regulatory submissions. For the absolute stereochemical assignment of chiral molecules we have developed a means of validating X-ray crystallographic stereochemical assignments of single crystals versus that of the bulk chemical by CD spectra.
Our circular dichroism service is led by George Tranter FRSC CChem CSci, an expert with over 30 years of experience in the field and a recognised international authority on the theory of CD, development of instrumentation, methodology and interpretation of spectra, especially in terms of pharmaceutical, biopharmaceutical and inorganic structure and behaviour.
A brief summary of CD and MCD follows below, but for more information see our detailed web pages on circular dichroism and its applications.
Circular Dichroism Spectroscopy
Circular Dichroism (CD) spectroscopy is a powerful technique that is sensitive to the chirality (handedness) of molecules. It provides a means of studying absolute stereochemistry, enantiomeric composition, racemisation, enantio-discriminatory phenomena, molecular interactions and conformations.
Furthermore it is often the method of choice for studying the higher-order structure of
biomacromolecules such as proteins, glycoproteins and DNA; subtle changes in the folding of the backbone
can be detected in realistic aqueous environments by CD in the far-UV wavelength range. Similarly, changes in the
environment of chromophoric residues (Trp, Tyr, Phe) and disulphides linkages can be monitored in the near-UV.
Other visible chromophoric groups such as haeme can be monitored in the visible wavelengths.
Variable temperature CD is a powerful means of studying subtle refolding, unfolding, denaturation and molten-globule states. In addition, the binding and association of achiral
species to chiral moieties (e.g. drug-protein or drug-DNA) can also be probed through their induced CD.
Magnetic Circular Dichroism Spectroscopy
When a powerful magnetic field is applied to the sample, it can can generate additional circular dichroism signals from molecules, whether chiral or not. The technique can be diagnostic of transition metal ions and their complexation and useful in the investigation of free radicals and species with unpaired electrons.
- please contact us to see how we may enhance your analytical capabilities or help solve your analysis problems.