顺磁弛豫增强(PRE)指未配对单电子与原子核之间的偶极相互作用导致了后者弛豫速率的加快.虽然对PRE的理论描述可追溯至上世纪50年代,但是运用于蛋白质结构的解析仅发生在最近10年.该综述中,首先阐述PRE的原理,介绍PRE实验所用的脉冲序列和1H核横向弛豫增强速率的两点时间测量法.其次,介绍目前所用的各种顺磁探针.接着,回顾近年来PRE在对蛋白质稳态和瞬态结构的研究中的应用.最后,对PRE的发展作了展望,包括差比顺磁弛豫增强(DiSPRE)技术,PRE新型探针的开发以及异核检测等,以期对蛋白质的溶液结构和动力学特性作出更完善的表征.
Paramagnetic relaxation enhancement(PRE) refers to acceleration of relaxation rates via dipole-dipole interactions between an unpaired electron and a nucleus.The theoretical framework of PRE was laid in the 1950s,yet its applications in studying protein structures only took place in the last decade.In this review,the theories underpinning PRE and the approaches to measure PRE rates are introduced.The commonly used paramagnetic probes for generating PRE in protein systems are reviewed.The principles of using PRE to characterize protein ground-state structure and transient excited-state structure are described.Further improvements of PRE techniques affording more detailed and comprehensive information regarding protein structure and dynamics are envisioned.