Department of Chemistry, The College of Staten Island, City University of New York (CUNY), Staten Island, NY, 10314.
Biopolymers. 2014 May;102(3):223-43. doi: 10.1002/bip.22490.
The structural characterization of G protein-coupled receptors has surged since the development of methodologies to facilitate the crystallization of these highly helical, seven transmembrane, integral membrane receptors. In the past seven years, eighteen GPCR structures were determined by X-ray crystallography. The crystal structures represent a static picture of these conformationally flexible signal transducers. Analyses that probe their dynamics and conformational changes require other techniques, in particular solution state nuclear magnetic resonance studies. Such investigations are challenged by the size of GPCRs, their α-helical structure, which limits resonance dispersion, their tendencies to aggregate in micellar preparations and their conformational heterogeneity. For many years, groups have been studying GPCR fragments as a means to overcome some of these difficulties. The results of these fragment analyses are presented here. Review of the literature reveals that much of the original work depended on circular dichroism, infra-red spectroscopy and fluorescence approaches. High resolution structures obtained by NMR are compared, where applicable, to the available crystal structures. In most cases, the work done on fragments by biophysical analysis is validated by these comparisons. Our perspective on the field of GPCR fragment analysis is presented together with the future goals that must be considered if work with fragments is continued.
自开发促进这些高度螺旋、七次跨膜、完整膜受体结晶的方法以来，G 蛋白偶联受体的结构特征研究呈爆炸式增长。在过去的七年中，已有十八种 GPCR 结构通过 X 射线晶体学确定。晶体结构代表了这些构象灵活的信号转导物的静态图像。探测它们的动力学和构象变化的分析需要其他技术，特别是溶液状态核磁共振研究。这些研究受到 GPCR 大小、限制共振分散的 α-螺旋结构、在胶束制剂中聚集的趋势以及构象异质性的限制。多年来，研究小组一直在研究 GPCR 片段，作为克服这些困难的一种手段。本文介绍了这些片段分析的结果。对文献的回顾表明，最初的许多工作依赖于圆二色性、红外光谱和荧光方法。通过 NMR 获得的高分辨率结构与现有的晶体结构进行了比较，在适用的情况下。在大多数情况下，通过生物物理分析对片段所做的工作都通过这些比较得到了验证。我们提出了对 GPCR 片段分析领域的看法，以及如果继续使用片段，必须考虑的未来目标。
