Liquid-liquid phase separation and static light scattering of concentrated ternary mixtures of bovine a and ?B crystallins

/Home/Analytical Methods & Tools for Lyophilization

Liquid-liquid phase separation and static light scattering of concentrated ternary mixtures of bovine a and ?B crystallins
Engineering Village 2
2006 Elsevier Inc.
Accession number: 8879721

Title: Liquid-liquid phase separation and static light scattering of concentrated ternary mixtures of bovine a and ?B crystallins

Authors: Thurston, G.M.1

Author affiliation: 1 Dept. of Phys., Rochester Inst. of Technol., NY, USA

Serial title: Journal of Chemical Physics

Abbreviated serial title: J. Chem. Phys. (USA)

Volume: 124

Issue: 13

Publication date: 7 April 2006

Pages: 134909-1-10

Language: English

ISSN: 0021-9606

CODEN: JCPSA6

Document type: Journal article (JA)

Publisher: AIP

Country of publication: USA

Material Identity Number: J008-2006-017

Abstract: We have used light scattering, turbidimetry, and thermodynamic analysis to study the phase diagram of concentrated aqueous mixtures of the bovine lens proteins, ?B crystallin, and a crystallin. We find that dilute a crystallin raises the phase separation temperature of concentrated ?B crystallin, while more concentrated a crystallin suppresses phase separation. Very concentrated a/?B mixtures can reversibly cloud above 37?C, even though ?B alone phase separates only below temperatures near 0?C, and a does not phase separate. At the scattering vector magnitude used, high-concentration a/?B mixtures scatter less light than the weighted average of their component a and ?B solutions, while low-concentration a/?B mixtures scatter more than such a weighted average. We use a mean-field thermodynamic analysis of such ternary mixtures to show that the observed light scattering and phase boundaries of a and ?B crystallin mixtures give evidence for prominent local fluctuations of relative protein composition. In the single phase, these fluctuations scatter comparatively little light, but are associated with enhanced thermodynamic instability. By applying this analysis to the experimental tie lines we estimate the magnitude of the saddlelike component of the free energy near the aqueous-?B critical point

Number of references: 42

Inspec controlled terms: bio-optics - biochemistry - critical points - fluctuations - free energy - light scattering - molecular biophysics - phase diagrams - phase separation - proteins

Uncontrolled terms: liquid-liquid phase separation - static light scattering - ternary mixture - turbidimetry - thermodynamic analysis - phase diagram - bovine lens proteins - scattering vector magnitude - phase boundaries - fluctuations - protein composition - free energy - critical point

Inspec classification codes: A8715D Physical chemistry of biomolecular solutions; condensed states - A8715M Interactions with radiations at the biomolecular level - A8750B Interactions of biosystems with radiations

Treatment: Experimental (EXP)

Discipline: Physics (A)

DOI: 10.1063/1.2168451

Database: Inspec

Copyright 2006, The Institution of Engineering and Technology
Subscription required: http://www.engineeringvillage2.org