Membrane position of a basic aromatic peptide that sequesters phosphatidylinositol 4,5 bisphosphate determined by site-directed spin labeling and high-resolution NMR
Membrane position of a basic aromatic peptide that sequesters phosphatidylinositol 4,5 bisphosphate determined by site-directed spin labeling and high-resolution NMR
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DOI：
10.1529/biophysj.104.046748
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发表时间：
2004-11-01
影响因子：
3.4
通讯作者：
Cafiso, DS
中科院分区：
文献类型：
--
作者：
Ellena, JF;Moulthrop, J;Cafiso, DS
膜的相互作用和位置的一个带正电荷的和高度芳香族肽来自分泌载体膜蛋白（SCAMP）检查使用磁共振光谱和几种生化方法。该肽（SCAMP-E）显示与含有磷脂酰肌醇4，5-二磷酸PI（4，5）P-2的膜结合，并将PI（4，5）P-2螯合在膜平面内。SCAMP-E肽的定点自旋标记表明膜结合SCAMP-E的位置和结构不因PI（4，5）P-2的存在而改变，并且肽骨架位于脂质磷酸盐水平以下的脂质界面内。使用高分辨率NMR的第二种方法用于生成SCAMP-E与双胞结合的模型。这种方法结合了氧增强核弛豫与计算方法对接的SCAMP-E肽在脂质界面。通过NMR产生的SCAMP模型与定点自旋标记的结果一致，并且将肽主链置于双层界面区域中，并且将芳族侧链置于脂烃区域内。SCAMP-E的带电侧链位于界面内，其中两个精氨酸残基位于比由脂质磷酸盐的位置限定的平面更深的位置。这些数据表明SCAMP-E通过不涉及特异性脂质-肽接触的静电机制与PI（4，5）P-2相互作用。这种相互作用可以通过在双层界面的低介电区域内的SCAMP-E上的带正电荷的侧链的位置来促进。
The membrane interactions and position of a positively charged and highly aromatic peptide derived from a secretory carrier membrane protein (SCAMP) are examined using magnetic resonance spectroscopy and several biochemical methods. This peptide (SCAMP-E) is shown to bind to membranes containing phosphatidylinositol 4,5-bisphosphate, PI(4,5)P-2, and sequester PI(4,5)P-2 within the plane of the membrane. Site-directed spin labeling of the SCAMP-E peptide indicates that the position and structure of membrane bound SCAMP-E are not altered by the presence of PI(4,5)P-2, and that the peptide backbone is positioned within the lipid interface below the level of the lipid phosphates. A second approach using high-resolution NMR was used to generate a model for SCAMP-E bound to bicelles. This approach combined oxygen enhancements of nuclear relaxation with a computational method to dock the SCAMP-E peptide at the lipid interface. The model for SCAMP generated by NMR is consistent with the results of site-directed spin labeling and places the peptide backbone in the bilayer interfacial region and the aromatic side chains within the lipid hydrocarbon region. The charged side chains of SCAMP-E lie well within the interface with two arginine residues lying deeper than a plane defined by the position of the lipid phosphates. These data suggest that SCAMP-E interacts with PI(4,5)P-2 through an electrostatic mechanism that does not involve specific lipid-peptide contacts. This interaction may be facilitated by the position of the positively charged side chains on SCAMP-E within a low-dielectric region of the bilayer interface.