Lysozyme Protein Solution with an Intermediate Range Order Structure

Journal Article · Sat Jan 01 04:00:00 EST 2011 · Journal of Physical Chemistry

DOI:https://doi.org/10.1021/jp109333c· OSTI ID:1010575

Liu, Yun ^[1]; Porcar, L. ^[1]; Chen, Wei-Ren ^[2]; Chen, Jinhong ^[3]; Falus, Peter ^[2]; Fratini, Emiliano ^[4]; Faraone, Antonio ^[1]; Baglioni, P ^[4]

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1. National Institute of Standards and Technology (NIST)
2. ORNL
3. Memorial Sloan-Kettering Cancer Center
4. University of Florence

The formation of equilibrium clusters has been studied in both a prototypical colloidal system and protein solutions. The appearance of a low-Q correlation peak in small angle scattering patterns of lysozyme solution was attributed to the cluster-cluster correlation. 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 signature of the formation of clusters. Rather, it is due to the formation of an intermediate range order structure governed by a 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.

• 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: 1010575
• Journal Information: Journal of Physical Chemistry, Journal Name: Journal of Physical Chemistry Journal Issue: 22 Vol. 115; ISSN XW239G; ISSN 1520-6106
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
59 BASIC BIOLOGICAL SCIENCES
DIFFUSION
LIFETIME
LYSOZYME
MONOMERS
NEUTRONS
PROTEINS
SCATTERING
SMALL ANGLE SCATTERING
SPIN ECHO
STATISTICAL MECHANICS