期刊
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
卷 110, 期 41, 页码 16309-16314出版社
NATL ACAD SCIENCES
DOI: 10.1073/pnas.1316150110
关键词
amphiphilic membranes; self-assembly; hydrophobic interaction
资金
- Department of Energy (DOE)-Basic Energy Sciences [DE-FG0208ER46539]
- Air Force Office of Scientific Research [FA9550-11-1-0275]
- Office of the Director of Defense Research and Engineering National Security Science
- Engineering Faculty Fellowship [FA9550-10-1-0167]
- National Science Foundation [DMR-1006713]
- US DOE [DE-AC02-06CH11357]
- Direct For Mathematical & Physical Scien
- Division Of Materials Research [1006713] Funding Source: National Science Foundation
The crystallization of molecules with polar and hydrophobic groups, such as ionic amphiphiles and proteins, is of paramount importance in biology and biotechnology. By coassembling dilysine (+2) and carboxylate (-1) amphiphiles of various tail lengths into bilayer membranes at different pH values, we show that the 2D crystallization process in amphiphile membranes can be controlled by modifying the competition of long-range and shortrange interactions among the polar and the hydrophobic groups. The pH and the hydrophobic tail length modify the intermolecular packing and the symmetry of their crystalline phase. For hydrophobic tail lengths of 14 carbons (C-14), we observe the coassembly into crystalline bilayers with hexagonal molecular ordering via in situ small-and wide-angle X-ray scattering. As the tail length increases, the hexagonal lattice spacing decreases due to an increase in van der Waals interactions, as demonstrated by atomistic molecular dynamics simulations. For C-16 and C-18 we observe a reentrant crystalline phase transition sequence, hexagonalrectangular- C-rectangular-P-rectangular-C-hexagonal, as the solution pH is increased from 3 to 10.5. The stability of the rectangular phases, which maximize tail packing, increases with increasing tail length. As a result, for very long tails (C-22), the possibility of observing packing symmetries other than rectangular-C phases diminishes. Ourwork demonstrates that it is possible to systematically exchange chemical and mechanical energy by changing the solution pH value within a range of physiological conditions at room temperature in bilayers of molecules with ionizable groups.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据