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Consistent picture of the reversible thermal unfolding of hen egg-white Lysozyme from experiment and molecular dynamics

Meersman, F. and Atilgan, C. and Miles, Andrew J. and Bader, R. and Shang, W. and Matagne, A. and Wallace, Bonnie A. and Koch, M.H.J. (2010) Consistent picture of the reversible thermal unfolding of hen egg-white Lysozyme from experiment and molecular dynamics. Biophysical Journal 99 (7), pp. 2255-2263. ISSN 0006-3495.

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Official URL: http://dx.doi.org/10.1016/j.bpj.2010.07.060

Abstract

Synchrotron radiation circular dichroism, Fourier transform infrared, and nuclear magnetic resonance spectroscopies, and small-angle x-ray scattering were used to monitor the reversible thermal unfolding of hen egg white lysozyme. The results were compared with crystal structures and high- and low-temperature structures derived from molecular-dynamics calculations. The results of both experimental and computational methods indicate that the unfolding process starts with the loss of β-structures followed by the reversible loss of helix content from not, vert, similar40% at 20°C to 27% at 70°C and not, vert, similar20% at 77°C, beyond which unfolding becomes irreversible. Concomitantly there is a reversible increase in the radius of gyration of the protein from 15 Å to 18 Å. The reversible decrease in forward x-ray scattering demonstrates a lack of aggregation upon unfolding, suggesting the change is due to a larger dilation of hydration water than of bulk water. Molecular-dynamics simulations suggest a similar sequence of events and are in good agreement with the 1HN chemical shift differences in nuclear magnetic resonance. This study demonstrates the power of complementary methods for elucidating unfolding/refolding processes and the nature of both the unfolded structure, for which there is no crystallographic data, and the partially unfolded forms of the protein that can lead to fibril formation and disease.

Item Type: Article
School or Research Centre: Birkbeck Schools and Research Centres > School of Science > Biological Sciences
Depositing User: Administrator
Date Deposited: 01 Apr 2011 10:44
Last Modified: 17 Apr 2013 12:20
URI: http://eprints.bbk.ac.uk/id/eprint/3242

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