Abstract

Our overall objective is to identify the microscopic molecular factors which produce the scattering elements responsible for lens opacification. These elements are high molecular weight protein aggregates, and spatially segregated protein-rich and protein-poor domains produced by phase separation. To achieve this objective we propose the following lines of investigation. 1. To determine the location of phase boundaries and the equation of state for aqueous solutions of highly purified alpha, beta and gamma crystallins and mixtures of these for fixed physiological solution conditions. 2. To determine the effect of changes in solution conditions such as pH, and ionic strength and ion identity on the location of phase boundaries and the equation of state for the lens protein solutions above. 3. To evaluate the consequences of specific covalent modifications on the location of phase boundaries and the formation of high molecular weight aggregates in two- component and multi-component protein solutions. 4. To determine the effect of noncovalently binding ligands on the location of the phase boundaries in two-component and multi-component protein solutions. 5. To use the data on equation of state and phase boundaries obtained above to determine the factors which control osmotic water balance within the lens. 6. To obtain a quantitative theoretical understanding of the structure of the Gibbs free energy which can predict the equilibrium properties of the lens protein solutions studied.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
4R37EY005127-13
Application #
2159307
Study Section
Special Emphasis Panel (NSS)
Project Start
1983-05-01
Project End
2000-06-30
Budget Start
1995-07-01
Budget End
1996-06-30
Support Year
13
Fiscal Year
1995
Total Cost
Indirect Cost

  Institution

Name
Massachusetts Institute of Technology
Department
Physics
Type
Schools of Arts and Sciences
DUNS #
City
Cambridge
State
MA
Country
United States
Zip Code
02139

  Publications

Wang, Ying; Lomakin, Aleksey; McManus, Jennifer J et al. (2010) Phase behavior of mixtures of human lens proteins Gamma D and Beta B1. Proc Natl Acad Sci U S A 107:13282-7
McManus, Jennifer J; Lomakin, Aleksey; Ogun, Olutayo et al. (2007) Altered phase diagram due to a single point mutation in human gammaD-crystallin. Proc Natl Acad Sci U S A 104:16856-61
Lomakin, A; Teplow, D B; Kirschner, D A et al. (1997) Kinetic theory of fibrillogenesis of amyloid beta-protein. Proc Natl Acad Sci U S A 94:7942-7
Walsh, D M; Lomakin, A; Benedek, G B et al. (1997) Amyloid beta-protein fibrillogenesis. Detection of a protofibrillar intermediate. J Biol Chem 272:22364-72
Lomakin, A; Chung, D S; Benedek, G B et al. (1996) On the nucleation and growth of amyloid beta-protein fibrils: detection of nuclei and quantitation of rate constants. Proc Natl Acad Sci U S A 93:1125-9
Pande, J; Ogun, O; Nath, C et al. (1993) Suppression of phase separation in bovine gamma IV crystallin solutions: effect of modification by charged versus uncharged polar groups. Exp Eye Res 57:257-64
Siezen, R J; Coppin, C M; Kaplan, E D et al. (1989) Oxidative modifications to crystallins induced in calf lenses in vitro by hydrogen peroxide. Exp Eye Res 48:225-35
Siezen, R J; Hom, C; Kaplan, E D et al. (1988) Heterogeneity of gamma-crystallins from spiny dogfish (Squalus acanthias) eye lens. Exp Eye Res 46:81-93
Siezen, R J; Wu, E; Kaplan, E D et al. (1988) Rat lens gamma-crystallins. Characterization of the six gene products and their spatial and temporal distribution resulting from differential synthesis. J Mol Biol 199:475-90
Clark, J I; Carper, D (1987) Phase separation in lens cytoplasm is genetically linked to cataract formation in the Philly mouse. Proc Natl Acad Sci U S A 84:122-5

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