Distinguishing the Monomer to Cluster Phase Transition in Concentrated Lysozyme Solutions by Studying the Temperature Dependence of the Short-Time Dynamics

Published

January 25, 2012

Author(s)

Peter Falus, Lionel Porcar, Emiliano Fratini, Wei-Ren Chen, Antonio Faraone, Kunlun Hong, Piero Baglioni, Yun Liu

Abstract

Recently experiments that combine both small angle neutron scattering (SANS) and Neutron Spin Echo (NSE) have demonstrated that dynamic clusters can form in concentrated lysozyme solutions when a right combination of a short-ranged attraction and long-ranged electrostatic repulsion exists. In this paper, we investigate the temperature effect on the dynamic cluster formation and try to pinpoint the transition concentration from a monomer phase to a cluster phase. Interestingly at even a relatively high concentration (10 % mass fraction), despite the significant change of the SANS patterns that are associated with the change of the short-ranged attraction among proteins, the normalized short-time self-diffusion coefficient is not affected. This is interpreted as a lack of cluster formation at this condition. However, at larger concentrations such as 17.5 % and 22.5 % mass fraction, we show that the average hydrodynamic radius increase significantly and causes a large decrease of the normalized self-diffusion coefficient as a results of cluster formation when the temperature is changed from 25 °C to 5 °C.

Citation

Journal of Physics Condensed Matter

Volume

24

Pub Type

Journals

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Keywords

Protein, Equilibrium Clusters, Dynamic Clusters, Neutron Spin Echo, Diffusion Coefficient

Citation

Falus, P. , Porcar, L. , Fratini, E. , Chen, W. , Faraone, A. , Hong, K. , Baglioni, P. and Liu, Y. (2012), Distinguishing the Monomer to Cluster Phase Transition in Concentrated Lysozyme Solutions by Studying the Temperature Dependence of the Short-Time Dynamics, Journal of Physics Condensed Matter, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=908571 (Accessed October 27, 2025)