Multi-Quantum Spin Counting and Long Range Distance Measurements by Pulsed EPR

通过脉冲 EPR 进行多量子自旋计数和长距离距离测量

• 批准号: 471089264
• 负责人: Professor Dr. Thomas F. Prisner
• 金额: --
• 依托单位: Institut für Physikalische und Theoretische Chemie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/471089264?language=en
• 关键词: Multi; Quantum; Spin; Counting; Long

Pulsed EPR methods allow to determine distances in the 1-10 nm range on macromolecules. This is done by measuring the magnetic dipole-dipole interactions between two covalently attached paramagnetic spin labels. In this project we want to extend these methods for the most common used nitroxide spin labels in two respects:1) Extending the measurable distance range by developing Carr-Purcell-SIFTER pulse sequences with broadband amplitude and frequency modulated microwave pulses. Such refocusing sequences decouple the electron spin from closeby nuclear spins and allow to prolong the observation time window. This is important for applications to large macromolecular systems with high internal flexibility (as for example intrinsically unfolded proteins, membrane protein complexes or protein-nucleic acid complexes). 2) Counting of the dipolar coupled electron spins in a complex by Multi-Quantum EPR experiments with broadband amplitude and frequency modulated microwave pulses.This would allow to determine for example oligomeric states of membrane protein complexes in their native lipid environment. The new type of experiments will be tested and optimized on model compounds and then applied to biological systems.

脉冲EPR方法允许确定大分子上1-10 nm范围内的距离。这是通过测量两个共价连接的顺磁性自旋标记之间的磁偶极-偶极相互作用来完成的。在这个项目中，我们希望从两个方面扩展这些方法用于最常用的氮氧自旋标记：1）通过开发具有宽带幅度和频率调制的微波脉冲的Carr-Purcell-SIFTER脉冲序列来扩展可测量的距离范围。这种重新聚焦序列将电子自旋与附近的核自旋解耦，并允许延长观察时间窗口。这对于应用于具有高内部柔性的大分子系统（例如固有未折叠的蛋白质、膜蛋白复合物或蛋白质-核酸复合物）是重要的。 2)通过宽带幅度和频率调制微波脉冲的多量子EPR实验计算复合物中的偶极耦合电子自旋。这将允许确定例如膜蛋白复合物在其天然脂质环境中的寡聚态。新型实验将在模型化合物上进行测试和优化，然后应用于生物系统。