2H-NMR study and molecular dynamics simulation of the location, alignment, and mobility of pyrene in POPC bilayers
2H-NMR study and molecular dynamics simulation of the location, alignment, and mobility of pyrene in POPC bilayers
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DOI：
10.1529/biophysj.104.052399
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发表时间：
2005-03-01
影响因子：
3.4
通讯作者：
Posten, C
中科院分区：
文献类型：
--
作者：
Hoff, B;Strandberg, E;Posten, C
采用固体核磁共振和分子动力学模拟两种方法研究了芘在1-棕榈酰-2-油酰-磷脂酰胆碱双层膜中的取向。定向脂双层中氘代芘-d（10）的H-2-NMR谱的四极分裂给出了关于C-D键相对于膜法线的取向的信息。从MD模拟，几何信息是通过轨迹访问。由德。通过计算分子和键级参数，可以直接比较分子动力学轨迹和核磁共振谱的数据。为了确保两种方法的结果具有可比性，选择实验和模拟设置的参数尽可能相似。从模拟中，我们看到芘更喜欢在脂质膜内靠近头部基团的位置，并且没有从膜的一个单层扩散到另一个单层的趋势。模拟和核磁共振的结果表明，分子平面的法线几乎垂直于双层法线。芘的长轴在+/-30度范围内优先平行于双层法线。两种不同方法的结果非常一致。这种良好的一致性可以解释为，芘分子的不同类型的运动已经在几纳秒内平均，这是MD模拟所覆盖的时间尺度。
The alignment of pyrene in a 1-palmitoyl-2-oleoyl-phosphatidylcholine bilayer was investigated using two different approaches, namely solid-state H-2-NMR spectroscopy and molecular dynamics ( MD) simulations. Quadrupolar splittings from H-2-NMR spectra of deuterated pyrene-d(10) in an oriented lipid bilayer give information about the orientation of C-D bonds with respect to the membrane normal. From MD simulations, geometric information is accessible via trajectories. By de. ning molecular and bond order parameters, the data from MD trajectories and NMR spectra can be compared straightforwardly. To ensure that the results from both methods are comparable, parameters of the experimental and the simulation setup were chosen to be as similar as possible. From simulations, we saw that pyrene prefers a position inside the lipid membrane near the headgroups and has no tendency to diffuse from one monolayer of the membrane to the other. The results from simulation and NMR show that the normal of the molecular plane is aligned nearly perpendicular to the bilayer normal. The long axis of pyrene lies preferentially parallel to the bilayer normal within a range of +/-30degrees. The results from the two different methods are remarkably consistent. The good agreement can be explained by the fact that the different kind of motions of a pyrene molecule are already averaged within a few nanoseconds, which is the timescale covered by the MD simulation.