波谱学杂志 ›› 2017, Vol. 34 ›› Issue (3): 257-265.doi: 10.11938/cjmr20162528

• 研究论文 • 上一篇    下一篇

固体核磁共振中膜蛋白双交叉极化效率与动力学参数相关的定量分析

孙毅1,2, 陈艳可1, 李建平1, 赵永祥1,2, 杨俊1   

  1. 1. 波谱与原子分子物理国家重点实验室, 武汉磁共振中心(中国科学院 武汉物理与数学研究所), 湖北 武汉 430071;
    2. 中国科学院大学, 北京 100049
  • 收稿日期:2016-05-15 修回日期:2017-08-01 出版日期:2017-09-05 发布日期:2017-09-05
  • 通讯作者: 杨俊,Tel:027-87199723,E-mail:yangjun@wipm.ac.cn. E-mail:yangjun@wipm.ac.cn
  • 基金资助:
    国家自然科学基金资助项目(10675162).

Efficiency of Double Cross Polarization in Magic-Angle Spinning Solid-State NMR Studies on Membrane Proteins

SUN Yi1,2, CHEN Yan-ke1, LI Jian-ping1, ZHAO Yong-xiang1,2, YANG Jun1   

  1. 1. State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan(Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences), Wuhan 430071, China;
    2. University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2016-05-15 Revised:2017-08-01 Online:2017-09-05 Published:2017-09-05

摘要: 固体核磁共振(NMR)中双交叉极化(DCP)是用于膜蛋白信号指认的多维异核相关实验的基本技术模块.DCP的效率在很大程度上决定了多维异核相关实验的效率.本文分析了3种典型的膜环境中的膜蛋白(AQPZ、DAGK和EV71 2B)的DCP效率及其影响因素.结果显示,在相同的实验条件下,3种蛋白样品的DCP效率存在明显差异:其中AQPZ的DCP效率最高(31%),DAGK的效率次之(23%),EV71 2B的效率最低(14%).通过测量它们在旋转坐标下的自旋-晶格弛豫时间(T1ρ)和偶极耦合常数(DHN),发现膜蛋白的运动会明显缩短T1ρ,但对DHN的影响较小.在实验的基础上,建立了T1ρ与DCP效率相关的模型,并基于DCP动力学的定量分析,证明了运动导致的T1ρ缩短是降低DCP效率的主要原因.因此,可以通过定量分析未知样品的T1ρ来预测其DCP的最优效率,为DCP实验的优化提供依据.

关键词: 固体核磁共振(NMR), 魔角旋转(MAS), 膜蛋白, 双交叉极化(DCP), 旋转坐标下的自旋-晶格弛豫时间(T1ρ)

Abstract: The efficiency of multiple-dimensional heteronuclear correlation experiments in membrane protein studies is partially determined by the efficiency of double cross polarization (DCP). DCP is a basic block in the pulse sequences to probe the connections between the 15N and 13C nuclei. In this study, three membrane proteins were studied experimentally to determine how the dynamics properties of the proteins affect the DCP efficiency in solid-state heteronuclear correlation experiments. Under the same experimental conditions, the AQPZ protein showed the highest DCP efficiency (31%), while the EV71 2B protein had the lowest efficiency (14%) and the DAGK protein in between (23%). Longitudinal lattice relaxation time in the rotating frame (T1ρ) and dipole coupling constant (DHN) were also measured for these proteins. It was found that the DCP efficiency depended strongly on T1ρ, but only weakly on DHN. Based on the experimental data, a model to correlate the T1ρ of protein to the DCP efficiency was established, with which the DCP efficiency could be predicted by measuring the T1ρ of membrane proteins.

Key words: solid-state NMR, magic-angle spinning (MAS), membrane protein, double cross polarization (DCP), T1ρ

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