Dipartimento di Scienze Chimiche, Università di Padova , via Marzolo 1, 35131 Padova, Italy.
J Am Chem Soc. 2014 May 7;136(18):6582-5. doi: 10.1021/ja502615n. Epub 2014 Apr 25.
This work demonstrates, for the first time, the feasibility of applying pulsed electron-electron double resonance (PELDOR/DEER) to determine the interspin distance between a photoexcited porphyrin triplet state (S = 1) and a nitroxide spin label chemically incorporated into a small helical peptide. The PELDOR trace shows deep envelope modulation induced by electron-electron dipole interaction between the partners in the pair, providing an accurate distance measurement. This new labeling approach has a high potential for measuring nanometer distances in more complex biological systems due to the sensitivity acquired from the spin polarization of the photoexcited triplet state spectrum.
这项工作首次证明了应用脉冲电子-电子双共振（PELDOR/DEER）来确定化学掺入小螺旋肽中的光激发卟啉三重态（S = 1）和氮氧自由基自旋标记之间的自旋间距的可行性。PELDOR 迹线显示了由对伴侣之间的电子-电子偶极相互作用引起的深包络调制，提供了准确的距离测量。由于从光激发三重态光谱的自旋极化获得的灵敏度，这种新的标记方法在更复杂的生物系统中测量纳米距离具有很高的潜力。
