Immobilization of the influenza A M2 transmembrane peptide in virus envelope-mimetic lipid membranes: a solid-state NMR investigation.
Immobilization of the influenza A M2 transmembrane peptide in virus envelope-mimetic lipid membranes: a solid-state NMR investigation.
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DOI：
10.1021/bi900716s
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发表时间：
2009-07-14
期刊：
影响因子：
2.9
通讯作者：
Hong, Mei
中科院分区：
文献类型：
--
作者：
Luo, Wenbin;Cady, Sarah D.;Hong, Mei
膜蛋白的动力学和结构特性受到脂质双层的密切影响。膜蛋白的一个特性是单轴旋转扩散，它取决于膜的黏度和厚度。这种旋转扩散在固态核磁共振谱中很容易表现为特征性的谱线形状以及与温度相关的谱线变窄或变宽。我们在此表明，在模拟真核细胞膜组成（富含胆固醇和鞘磷脂）的脂质双层中，这种整体单轴扩散受到抑制。我们通过甲型流感M2（AM2 - TM）质子通道蛋白的跨膜肽证明了这种由膜诱导的固定化。在生理温度下，AM2 - TM在二棕榈酰磷脂酰胆碱（DLPC）、二肉豆蔻酰磷脂酰胆碱（DMPC）和棕榈酰油酰磷脂酰胆碱（POPC）双层中进行单轴扩散的速度快于约10⁵ s⁻¹，但在富含胆固醇的病毒包膜模拟膜（“病毒膜”）中，其运动速度减慢了两个数量级，降至<10³ s⁻¹。这种固定化表现为所有标记残基的接近刚性极限的²H四极耦合以及¹³C - ¹H、¹⁵N - ¹H和¹³C - ¹⁵N偶极耦合。这种固定化抑制了核磁共振谱在中间时间尺度上的展宽，从而使得在生理温度下能够测量到高灵敏度和高分辨率的谱图。病毒膜中蛋白质的构象比在磷脂酰胆碱（PC）模型膜中更均匀，这由狭窄的¹⁵N谱线所证明。膜组成变化对M2螺旋束的固定化表明在尽可能接近天然的环境中研究膜蛋白的重要性。这也表明模拟真核生物的脂质膜可能极大地促进通过固态核磁共振确定膜蛋白的结构。
The dynamic and structural properties of membrane proteins are intimately affected by the lipid bilayer. One property of membrane proteins is uniaxial rotational diffusion, which depends on the membrane viscosity and thickness. This rotational diffusion is readily manifested in solid-state NMR spectra as characteristic lineshapes and temperature-dependent line narrowing or broadening. We show here that this whole-body uniaxial diffusion is suppressed in lipid bilayers mimicking the composition of eukaryotic cell membranes, which are rich in cholesterol and sphingomyelin. We demonstrate this membrane-induced immobilization on the transmembrane peptide of the influenza A M2 (AM2-TM) proton channel protein. At physiological temperature, AM2-TM undergoes uniaxial diffusion faster than ~ 105 s−1 in DLPC, DMPC and POPC bilayers, but the motion is slowed by two orders of magnitude, to < 103 s−1, in a cholesterol-rich virus-envelope-mimetic membrane (“viral membrane”). The immobilization is manifested as near rigid-limit 2H quadrupolar couplings and 13C-1H, 15N-1H and 13C-15N dipolar couplings for all labeled residues. The immobilization suppresses intermediate time scale broadening of the NMR spectra, thus allowing high-sensitivity and high-resolution spectra to be measured at physiological temperature. The conformation of the protein in the viral membrane is more homogeneous than in model PC membranes, as evidenced by the narrow 15N lines. The immobilization of the M2 helical bundle by the membrane composition change indicates the importance of studying membrane proteins in as native environments as possible. It also suggests that eukaryote-mimetic lipid membranes may greatly facilitate structure determination of membrane proteins by solid-state NMR.
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影响因子：
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作者：
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通讯作者：
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DOI：
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发表时间：
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影响因子：
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发表时间：
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影响因子：
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