Prestrelski S J, Arakawa T, Kenney W C, Byler D M
Protein Chemistry Department, Amgen Inc., Thousand Oaks, California 91320.
Arch Biochem Biophys. 1991 Feb 15;285(1):111-5. doi: 10.1016/0003-9861(91)90335-g.
The secondary structures of two recombinant human growth factors, platelet-derived growth factor and the basic fibroblast growth factor, have been quantitatively examined by using Fourier transform infrared spectroscopy. These studies, carried out in D2O, focus on the conformation-sensitive amide I region. Resolution enhancement techniques, including Fourier self-deconvolution and derivative spectroscopy, were combined with band fitting techniques to quantitate the spectral information from the broad, overlapped amide I band. The results presented here indicate that both proteins are rich in beta-structures. The remainder of the platelet-derived growth factor exists largely as irregular or disordered conformations with a moderate amount of alpha-helix and a small portion of reverse turns. By contrast, the basic fibroblast growth factor is much richer in reverse turn structures and contains a lesser portion of irregularly folded or disordered structures. Based on circular dichroism studies which indicate no alpha-helix in bFGF, components near 1655 cm-1 in the bFGF spectra are tentatively assigned to loops. The results of this study emphasize the need for using a combination of circular dichroism and infrared studies for spectroscopic characterization of protein secondary structure.
利用傅里叶变换红外光谱法对两种重组人生长因子——血小板衍生生长因子和碱性成纤维细胞生长因子的二级结构进行了定量研究。这些在重水中进行的研究聚焦于对构象敏感的酰胺I区域。分辨率增强技术，包括傅里叶自去卷积和导数光谱法，与谱带拟合技术相结合，以量化来自宽泛、重叠的酰胺I谱带的光谱信息。此处呈现的结果表明，这两种蛋白质都富含β结构。血小板衍生生长因子的其余部分主要以不规则或无序构象存在，有适量的α螺旋和一小部分反向转角。相比之下，碱性成纤维细胞生长因子富含更多的反向转角结构，且含有较少比例的不规则折叠或无序结构。基于圆二色性研究表明碱性成纤维细胞生长因子中不存在α螺旋，碱性成纤维细胞生长因子光谱中1655 cm-1附近的成分暂定为环。本研究结果强调了结合使用圆二色性和红外研究对蛋白质二级结构进行光谱表征的必要性。
