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Spectroscopy
Volume 24 (2010), Issue 3-4, Pages 239-244
http://dx.doi.org/10.3233/SPE-2010-0472

Structural organization of DNA–protein complexes of chromatin studied by vibrational and electronic circular dichroism

Alexander Polyanichko1,3 and Helmut Wieser2

1Department of Molecular Biophysics, Faculty of Physics of Saint-Petersburg State University and Institute of Cytology RAS, Saint-Petersburg, Russia
2Department of Chemistry, University of Calgary, Calgary, Alberta, Canada
3Department of Molecular Biophysics, Faculty of Physics of Saint-Petersburg State University, 1 Uljanovskaya Str., Stary Petergoff, Saint-Petersburg 198504, Russia

Copyright © 2010 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Structure and functioning of chromatin is determined by interactions of DNA with numerous nuclear proteins. The most abundant and yet not completely understood non-histone chromosomal proteins are those belonging to a High Mobility Group (HMG) namely HMGB1. The interplay of this protein on DNA with linker histone H1 and other proteins determines both structure and functioning of the chromatin. A combination of UV and IR absorption and circular dichroism (CD) spectroscopy was applied to investigate the structure and formation of large supramolecular DNA–protein complexes. This combination of techniques was used to overcome limitations of UV-CD (ECD) spectroscopy due to considerable light scattering in such solutions. Based on the analysis of FTIR and UV circular dichroism spectra and AFM imaging the interaction of DNA with high-mobility group non-histone chromatin protein HMGB1 and linker histone H1 was studied.