TY - JOUR
T1 - Distinguishing the monomer to cluster phase transition in concentrated lysozyme solutions by studying the temperature dependence of the short-time dynamics
AU - Falus, Péter
AU - Porcar, Lionel
AU - Fratini, Emiliano
AU - Chen, Wei Ren
AU - Faraone, Antonio
AU - Hong, Kunlun
AU - Baglioni, Piero
AU - Liu, Yun
PY - 2012/2/15
Y1 - 2012/2/15
N2 - Recent combined experiments by small angle neutron scattering (SANS) and neutron spin echo (NSE) have demonstrated that dynamic clusters can form in concentrated lysozyme solutions when the right combination of a short-ranged attraction and a 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 monomeric protein phase to a cluster phase. Interestingly, even at a relatively high concentration (10% mass fraction), despite the significant change in 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 between 5 and 40°C. This is interpreted as a lack of cluster formation in this condition. However, at larger concentrations such as 17.5% and 22.5% mass fraction, we show that the average hydrodynamic radius increases significantly and causes a large decrease of the normalized self-diffusion coefficient as a result of cluster formation when the temperature is changed from 25 to 5°C.
AB - Recent combined experiments by small angle neutron scattering (SANS) and neutron spin echo (NSE) have demonstrated that dynamic clusters can form in concentrated lysozyme solutions when the right combination of a short-ranged attraction and a 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 monomeric protein phase to a cluster phase. Interestingly, even at a relatively high concentration (10% mass fraction), despite the significant change in 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 between 5 and 40°C. This is interpreted as a lack of cluster formation in this condition. However, at larger concentrations such as 17.5% and 22.5% mass fraction, we show that the average hydrodynamic radius increases significantly and causes a large decrease of the normalized self-diffusion coefficient as a result of cluster formation when the temperature is changed from 25 to 5°C.
UR - http://www.scopus.com/inward/record.url?scp=84863012551&partnerID=8YFLogxK
U2 - 10.1088/0953-8984/24/6/064114
DO - 10.1088/0953-8984/24/6/064114
M3 - Article
AN - SCOPUS:84863012551
SN - 0953-8984
VL - 24
JO - Journal of Physics Condensed Matter
JF - Journal of Physics Condensed Matter
IS - 6
M1 - 064114
ER -