Department of Chemistry and Biochemistry, Miami University, Oxford, OH 45056, USA.
Biochemistry. 2012 Sep 25;51(38):7417-9. doi: 10.1021/bi3010736. Epub 2012 Sep 14.
A new method has been developed to determine α-helical and β-sheet secondary structural components of aqueous and membrane-bound proteins using pulsed electron paramagnetic resonance (EPR) spectroscopy. The three-pulse electron spin echo envelope modulation (ESEEM) technique was used to detect weakly coupled (2)H-labeled nuclei on side chains in the proximity of a strategically placed nitroxide spin-label up to 8 Å away. Changes in the ESEEM spectra for different samples correlate directly to periodic structural differences between α-helical and β-sheet motifs. These distinct trends were demonstrated with α-helical (M2δ subunit of the acetylcholine receptor) and β-sheet (ubiquitin) peptides in biologically relevant sample environments.
一种新的方法已经被开发出来，用于使用脉冲电子顺磁共振（EPR）光谱法测定水相和膜结合蛋白的α-螺旋和β-折叠二级结构成分。三脉冲电子自旋回波包络调制（ESEEM）技术被用于检测在 strategically placed nitroxide spin-label 附近的弱偶合（2）H 标记侧链核，距离可达 8 Å。不同样品的 ESEEM 光谱的变化直接与α-螺旋和β-折叠基序之间的周期性结构差异相关。这些明显的趋势在生物相关的样品环境中通过α-螺旋（乙酰胆碱受体的 M2δ 亚基）和β-折叠（泛素）肽得到了证明。
