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Lysozyme Protein Solution with an Intermediate Range Order Structure



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


The formation of equilibrium clusters has been studied in both prototypical colloidal system and protein solution. The appearance of a low-Q correlation peak in small angle scattering patterns of lysozyme solution was attributed to the cluster-cluster correlation. And consequently the presence of long lived clusters has been established. By quantitatively analyzing both the SANS (Small angle Neutron Scattering) and NSE (Neutron Spin Echo) data of lysozyme solution using statistical mechanics models, we conclusively show in this paper that the appearance of a low-Q peak is not a characteristic feature of the formation of clusters. Rather it is due to the formation of intermediate range order structure governed by the short-range attraction and a long-range repulsion. We have further studied dynamic features of a sample with high enough concentration at which clusters are formed in solution. From the estimation of the mean square displacement by using short-time and long-time diffusion coefficient measured by NSE and NMR, we find that these clusters are not permanent but have a finite lifetime longer than the time required to diffuse over a distance of a monomer diameter.
Journal of Physical Chemistry B


Protein, Equilibrium Clusters, Dynamic Clusters, Small Angle Neutron Scattering, Neutron Spin Echo, Diffusion Coefficient


Liu, Y. , Porcar, L. , Chen, J. , Chen, W. , Falus, P. , Faraone, A. , Fratini, E. and Baglioni, P. (2009), Lysozyme Protein Solution with an Intermediate Range Order Structure, Journal of Physical Chemistry B, [online], (Accessed July 14, 2024)


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Created November 10, 2009, Updated February 19, 2017