期刊
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
卷 111, 期 47, 页码 16748-16753出版社
NATL ACAD SCIENCES
DOI: 10.1073/pnas.1406990111
关键词
alpha crystallin; scattering; mode-coupling theory; molecular dynamics; glass transition
资金
- Swiss National Science Foundation [PP0022_119006, PP00P2_140822/1, 200020-109499, 200020-117755, 200021-127192, PBELP2-130895]
- State Secretariat for Education and Research of Switzerland
- Marie Curie Network on Dynamical Arrest of Soft Matter and Colloids [MCRTN-CT-2003504712]
- Swedish Research Council [621-2012-2422, 2009-6794]
- National Eye Institute of the National Institutes of Health [R15EY018249]
- Swiss National Science Foundation (SNF) [PP00P2_140822, PP0022_119006, 200021_127192, PBELP2-130895] Funding Source: Swiss National Science Foundation (SNF)
We study the equilibrium liquid structure and dynamics of dilute and concentrated bovine eye lens alpha-crystallin solutions, using small-angle X-ray scattering, static and dynamic light scattering, viscometry, molecular dynamics simulations, and mode-coupling theory. We find that a polydisperse Percus-Yevick hard-sphere liquid-structure model accurately reproduces both static light scattering data and small-angle X-ray scattering liquid structure data from alpha-crystallin solutions over an extended range of protein concentrations up to 290 mg/mL or 49% vol fraction and up to ca. 330 mg/mL for static light scattering. The measured dynamic light scattering and viscosity properties are also consistent with those of hard-sphere colloids and show power laws characteristic of an approach toward a glass transition at alpha-crystallin volume fractions near 58%. Dynamic light scattering at a volume fraction beyond the glass transition indicates formation of an arrested state. We further perform event-driven molecular dynamics simulations of polydisperse hard-sphere systems and use mode-coupling theory to compare the measured dynamic power laws with those of hard-sphere models. The static and dynamic data, simulations, and analysis show that aqueous eye lens alpha-crystallin solutions exhibit a glass transition at high concentrations that is similar to those found in hard-sphere colloidal systems. The alpha-crystallin glass transition could have implications for the molecular basis of presbyopia and the kinetics of molecular change during cataractogenesis.
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