Identifying monomer phases and cluster phases in lysozyme solutions by studying the temperature dependence of the short-time dynamics

Journal Article · Sun Jan 01 04:00:00 EST 2012 · Journal of Physics: Condensed Matter

OSTI ID:1037637

Baglioni, P ^[1]; Chen, Wei-Ren ^[2]; Falus, Peter ^[2]; Faraone, Antonio ^[3]; Fratini, Emiliano ^[1]; Hong, Kunlun ^[2]; Liu, Yun ^[3]; Porcar, L. ^[3]

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1. University of Florence
2. ORNL
3. National Institute of Standards and Technology (NIST)

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 there is a right combination of a short-ranged attraction and a long-ranged electrostatic repulsion. In this paper, we study 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 due to the fact that there is no 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 when the temperature is changed from 25 oC to 5 oC indicating the formation of dynamic clusters in solution.

• Research Organization: Oak Ridge National Laboratory (ORNL); Center for Nanophase Materials Sciences; Spallation Neutron Source
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1037637
• Journal Information: Journal of Physics: Condensed Matter, Journal Name: Journal of Physics: Condensed Matter Vol. 24
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
99 GENERAL AND MISCELLANEOUS
ELECTROSTATICS
HYDRODYNAMICS
LYSOZYME
MONOMERS
NEUTRON DIFFRACTION
PROTEINS
SELF-DIFFUSION
SMALL ANGLE SCATTERING
SPIN ECHO
TEMPERATURE DEPENDENCE