An-harmonic behaviour in the multi-subunit protein apoferritin as revealed by quasi-elastic neutron scattering

Telling, M; Neylon, C; Arrighi, V; Kilcoyne, SH

Abstract

Quasi-elastic neutron scattering (QENS) has been used to study the deviation from Debye-law
harmonic behaviour in lyophilized and hydrated apoferritin; a naturally occurring, multisubunit
protein. While analysis of the measured mean squared displacement (msd) parameter
reveals a hydration-dependent inflection above 240 K, characteristic of diffusive motion, a
hydration-independent inflection is observed at 100 K. The mechanism responsible for this
low temperature an-harmonic response is further investigated, via analysis of the elastic
incoherent neutron scattering intensity, by applying models developed to describe side group
motion in glassy polymers. Our results suggest that the deviation from harmonic behaviour is
due of the onset of methyl group rotations which exhibit a broad distribution of activated
processes (Ea,ave =12.2 kJ.mol-1, � = 5.0 kJ.mol�1). Our results are likened to those reported
for other proteins.

Citation

Telling, M., Neylon, C., Arrighi, V., & Kilcoyne, S. An-harmonic behaviour in the multi-subunit protein apoferritin as revealed by quasi-elastic neutron scattering. Journal of Physical Chemistry B, 112(35), 10873-10878. https://doi.org/10.1021/jp801779x

• Journal Article Type: Article
• Deposit Date: Sep 22, 2010
• Journal: Journal of Physical Chemistry B
• Print ISSN: 1520-6106
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• Volume: 112
• Issue: 35
• Pages: 10873-10878
• DOI: https://doi.org/10.1021/jp801779x
• Publisher URL: http://www.ncbi.nlm.nih.gov/pubmed/18698713