Circular Dichroism under GMP and GLP guidelines

PrimeSyn Lab Inc. offers Circular Dichroism (CD analysis of proteins and nucleic acids) and thermal denaturation services. Circular dichroism (CD) spectroscopy is a form of light absorption spectroscopy that measures the difference in absorbance of right- and left-circularly polarized light by a substance.

Use of Circular Dichroism:

• secondary structure content of macromolecules
• conformation of proteins and nucleic acids-effects of salt, pH, organics
• kinetics-protein folding, unfolding, denaturation or aggregation
• thermodynamics-protein stability to temperature or chemical denaturants

A list of programs available for secondary structure deconvolution (Circular Dichroism):

• SELCON
• VARSLC
• K2D (home page: http://www.embl-heidelberg.de/~andrade/k2d.html)
• Antheprot (http://dicroprot-pbil.ibcp.fr/)
• CONTIN
• CDPRO

Useful review article in the field of Circular dichroism (CD analysis of proteins):

1. Circular Dichroism and Optical Rotary Dispersion of Proteins and Polypeptides, A.J.Alder, N.J.Greenfield and G.D.Fasman, Meth. Enzymology 27, 675 (1973).
2. Computed Circular Dichroism Spectra for the Evaluation of Protein Conformation, N.Greenfield and G.D.Fasman, Biochemistry 8 (10), 4108 (1969)
3. C.R.Cantor and P.R.Schimmel, Biophysical Chemistry, Vol.2, Chapter 8 (1980)
4. Effect of Trifluoroethanol on Protein Secondary Structure, F.D.Soennichsen, J.E.VanEyk, R.S.Hodges and B.D.Sykes, Biochemistry 31 (37),8791 (1992)
5. Protein Secondary Structure and Circular Dichroism : A Practical Guide, W.C.Johnson, PROTEINS 7, 205-214 (1990)
6. Fasman, G.D., Circular Dichroism and the Conformational Analysis of Biomolecules (1996) Plenum Press, New York.
7. Hecht, E., Optics 3rd Edition (1998) Addison Wesley Longman, Massachusetts.
8. Klewpatinond, M. and Viles, J.H. (2007) Empirical rules for rationalising visible circular dichroism of Cu2+ and Ni2+ histidine complexes: Applications to the prion protein. FEBS Letters 581, 1430-1434.

Some Useful Web site for Circular Dichroism:

Excellent animation site explaining electromagnetic waves (Circular Dichroism)

Circular Dichroism Handout by Norma J. Greenfield

Fluorescence Analysis:

PrimeSyn Lab also offers fluorescence analysis of both protein and nucleic acid derivatives. This technique is useful in determining the tryptophan derivatives.