Proteins CD spectroscopy

The advent of recombinant DNA technology has led to an increased interest in the structural characterization of proteins by spectroscopic methods. Few spectroscopic techniques can provide the amount of information regarding protein secondary and tertiary structure which can be obtained from circular dichroism (CD) spectroscopy. In this chapter we describe the capabilities of CD spectroscopy to provide details on the globular structure of proteins. In addition, we will provide an overview of quantitative secondary structure estimates via CD spectroscopy and of specialized CD methods for studying proteins in contact with membranes and other biomolecules. Certain aspects of protein CD spectroscopy have been previously reviewed [1-19]. 

In addition to this application to globular proteins, CD spectroscopy is one of the only effective techniques for identifying the presence of left-handed Pn-helix structures (AAmax 225 nm) that make up the anatomy of collagen and collagen-like fibrous proteins (Figure 4.7)... 

Circular dichroism (CD) spectroscopy is a form of absorption spectroscopy that is based on measuring the difference in the absorbance by a substance of right- or left-circularly polarized light. CD is exhibited by chiral molecules, and represents a powerful tool for revealing the structures of biological macromolecules such as polypeptides, proteins and nucleic acids in solution. In the case of proteins, CD spectroscopy not only allows the discrimination between the different structural types, such as a-helix, parallel and antiparallel (3-pleated sheets and (3-turns, but also permits an estimation of the relative contents of these structures. This is... 

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