In situ investigation of Heterotrimeric G protein βγ subunit binding and orientation on membrane bilayers
In situ investigation of Heterotrimeric G protein βγ subunit binding and orientation on membrane bilayers
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DOI：
10.1021/ja075542w
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发表时间：
2007-10-24
影响因子：
15
通讯作者：
Chen, Zhan
中科院分区：
文献类型：
--
作者：
Chen, Xiaoyun;Boughton, Andrew P.;Chen, Zhan
本文研究了一种重要的信号转导膜蛋白GβY-1(2)在膜双层中的结合和定位。这是第一次使用和频产生(SFG)振动光谱来推断外周膜蛋白在膜环境中的取向。野性的。和可溶性GβY-1(2)亚基的研究结果进行比较，以评价香叶基香叶基团的锚定作用。SFG研究表明，在没有香叶基的情况下，GβY-1(2)吸附在膜表面，而β推进器面向膜表面。在此方向上，螺旋域的方向与表面大致平行。相反，野生型GβY-1(2)通过香叶基香叶基与P推进器或多或少垂直于表面锚定在膜上。在这种情况下，螺旋域不再平行于表面，因此贡献了主要的光谱特征。根据测量的SFG PPP和SSP强度比，发现Gβ(1)Y-2沿y轴的取向约为-35度。SFG结果还表明，脂质成分可以调节GβY-1(2)的整体分子取向或GβY-1(2)的三级结构。
This paper investigates the binding and orientation of an important signal transduction membrane protein, G beta Y-1(2), in a membrane bilayer. This is the first time that sum frequency generation (SFG) vibrational spectroscopy has been used to deduce the orientation of a peripheral membrane protein in the membrane environment. Wild-type. and soluble G beta Y-1(2) subunits were studied and the results are compared to evaluate the anchoring role of the geranylgeranyl group. SFG studies show that without the geranylgeranyl group, G beta Y-1(2) adsorbs onto the surface with the beta-propeller facing the membrane surface. At this orientation the helical domains orient more or less parallel to the surface. In contrast, wild-type G beta Y-1(2) is anchored to the membrane via the geranylgeranyl group with the P propeller more or less perpendicular to the surface. Under this circumstance, the helical domains are no longer parallel to the surface and hence contribute the dominant spectral features. From the measured SFG ppp and ssp intensity ratio, the orientation of the G beta(1) Y-2 is found to be about -35 degrees around the y -axis. SFG results also indicate that lipid compositions can modulate either the overall G beta Y-1(2) molecular orientation or the tertiary structure of G beta Y-1(2).