Purchase this article with an account.
GM Thurston, V Lobaskin, L Lurio, P Schurtenberger, S Mochrie; Comparison of Monte Carlo Simulations with X-ray Scattering from High Concentration Mixtures of Alpha and Gamma-B Crystallins . Invest. Ophthalmol. Vis. Sci. 2002;43(13):4655.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Purpose:To study whether X-ray scattering data, reflecting the liquid structure of high concentration α and γ B crystallin mixtures, can be reproduced by Monte Carlo simulation of particles interacting via simple, appropriate model potentials. Methods:Model γ B-γ B interactions combined hard-core repulsion of effective spheres with an attractive Yukawa potential . α-α and α-γ B interactions were represented by hard-core repulsion alone. The Yukawa range and depth were chosen using the known critical volume fraction and critical temperature for γ B-crystallin. Effective sphere sizes were chosen using the known molecular volume of γ B, and the radius of gyration observed by X-ray scattering for α. For X-ray scattering, calf lens proteins were isolated using size-exclusion and ion-exchange chromatography, concentrated by ultrafiltration, and analyzed in solutions containing 0.1 M sodium phosphate buffer, pH 7.1, with 20mM dithiothreitol. The X-ray scattering intensity, I(q), as a function of wavevector, q, was measured in the range 0.04 < q < 6 nm-1, using Beamline 8-ID at the Advanced Photon Source. Results:We find nearly quantitative agreement between the simulated I(q) and the measured I(q), at a total protein concentration of 260 mg/ml, for α-crystallin relative proportions ranging from 0 to 1. Refinements to incorporate more realistic γ B-crystallin shape may be needed. Conclusion:Simple model potentials such as these can provide useful starting points for understanding the liquid structure of lens crystallin mixtures, at concentrations comparable to those in the eye lens.
This PDF is available to Subscribers Only