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Dynamics and structures in protein s...

Pan, Weichun.

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Dynamics and structures in protein solutions.

Record Type:	Language materials, printed : Monograph/item
Title/Author:	Dynamics and structures in protein solutions./
Author:	Pan, Weichun.
Description:	112 p.
Notes:	Adviser: Peter Vekilov.
Contained By:	Dissertation Abstracts International68-01B.
Subject:	Biophysics, General. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3250702

Dynamics and structures in protein solutions.
Pan, Weichun.

Dynamics and structures in protein solutions. - 112 p.

Adviser: Peter Vekilov.

Thesis (Ph.D.)--University of Houston, 2006.

Proteins are important biomaterials as they take part in every aspect of biological function and regulation in living creatures. The intermolecular interaction is a crucial parameter for the properties of the protein solutions. To characterize the role of water in the intermolecular interactions, we applied static light scattering to protein solution and determined the second virial coefficient of the protein molecules. We used the concentration of the two phases in liquid-liquid phase equilibrium to determine the third and fourth virial coefficients. From the virial expansion of the protein chemical potential, using the Kirkwood-Buff method, we quantified the water molecules lost during protein crystallization. This number was tracked as a function of protein concentration, temperature, and solution ionic strength. The results indicate that the water attached to the protein surface is distinctly subdivided into two layers, one tightly attached and the other loosely surrounding the surface. By tuning this interaction at specific conditions, the protein aggregation and clustering behavior can be controlled. We also found that in protein solutions, cluster of dense liquid exist at nearly all tested conditions. These clusters are several hundred nanometers in sizes, "mesoscopic", and are metastable but not unstable with respect to the protein solution. If the solution is supersaturated with respect to a crystalline phase, the clusters serve as nuclei of the crystal nucleus. We show that several protein phase transitions leading to the formation of an ordered solid from the protein solution use the clusters as an intermediate step in the nucleation mechanism. In this way, the free energy barrier for the formation of the new phase is lowered. In further developments, we developed a phenomenological kinetic model. The model resulted in a quantitative correlation between the nucleation rate of protein crystals and the temperature and protein concentration for systems for which the two step mechanism operates. The model highlights the crucial role that the viscosity of the solution plays in nucleation. We found a paucity of data and understanding of the fundamentals of viscosity in protein and protein-like solutions. We found that the existing theories are adequate to describe the viscosity dependencies on temperature and concentration only at low protein concentration.Subjects--Topical Terms:

1019105
Biophysics, General.

Dynamics and structures in protein solutions.
LDR:03198nam 2200253 a 45 001 970840
005 20110921
008 110921s2006 eng d
035 $a (UMI)AAI3250702
035 $a AAI3250702
040 $a UMI $c UMI
100 1 $a Pan, Weichun. $3 1294880
245 1 0 $a Dynamics and structures in protein solutions.
300 $a 112 p.
500 $a Adviser: Peter Vekilov.
500 $a Source: Dissertation Abstracts International, Volume: 68-01, Section: B, page: 0150.
502 $a Thesis (Ph.D.)--University of Houston, 2006.
520 $a Proteins are important biomaterials as they take part in every aspect of biological function and regulation in living creatures. The intermolecular interaction is a crucial parameter for the properties of the protein solutions. To characterize the role of water in the intermolecular interactions, we applied static light scattering to protein solution and determined the second virial coefficient of the protein molecules. We used the concentration of the two phases in liquid-liquid phase equilibrium to determine the third and fourth virial coefficients. From the virial expansion of the protein chemical potential, using the Kirkwood-Buff method, we quantified the water molecules lost during protein crystallization. This number was tracked as a function of protein concentration, temperature, and solution ionic strength. The results indicate that the water attached to the protein surface is distinctly subdivided into two layers, one tightly attached and the other loosely surrounding the surface. By tuning this interaction at specific conditions, the protein aggregation and clustering behavior can be controlled. We also found that in protein solutions, cluster of dense liquid exist at nearly all tested conditions. These clusters are several hundred nanometers in sizes, "mesoscopic", and are metastable but not unstable with respect to the protein solution. If the solution is supersaturated with respect to a crystalline phase, the clusters serve as nuclei of the crystal nucleus. We show that several protein phase transitions leading to the formation of an ordered solid from the protein solution use the clusters as an intermediate step in the nucleation mechanism. In this way, the free energy barrier for the formation of the new phase is lowered. In further developments, we developed a phenomenological kinetic model. The model resulted in a quantitative correlation between the nucleation rate of protein crystals and the temperature and protein concentration for systems for which the two step mechanism operates. The model highlights the crucial role that the viscosity of the solution plays in nucleation. We found a paucity of data and understanding of the fundamentals of viscosity in protein and protein-like solutions. We found that the existing theories are adequate to describe the viscosity dependencies on temperature and concentration only at low protein concentration.
590 $a School code: 0087.
650 4 $a Biophysics, General. $3 1019105
690 $a 0786
710 2 0 $a University of Houston. $3 1019266
773 0 $t Dissertation Abstracts International $g 68-01B.
790 $a 0087
790 1 0 $a Vekilov, Peter, $e advisor
791 $a Ph.D.
792 $a 2006
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3250702