Coupled protein domain motion in Taq polymerase revealed by neutron spin-echo spectroscopy
Coupled protein domain motion in Taq polymerase revealed by neutron spin-echo spectroscopy
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DOI：
10.1073/pnas.0503388102
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发表时间：
2005-12-06
影响因子：
11.1
通讯作者：
Callaway, DJE
中科院分区：
文献类型：
--
作者：
Bu, ZM;Biehl, R;Callaway, DJE
蛋白质的长程构象变化在生物学中普遍存在，用于信号的传递和放大;这种构象变化可以由小幅度的纳秒蛋白质结构域运动触发。了解构象变化是如何启动的，需要在这些时间尺度上和与蛋白质尺寸相当的长度尺度上表征蛋白质结构域运动。使用中子自旋回波光谱（NSE），正常模式分析，和一个螺旋机械框架，我们揭示过阻尼，耦合域运动内的DNA聚合酶I从水生栖热菌（Taq聚合酶）。这种蛋白质利用超过70埃的相关结构域动力学来协调DNA合成和修复过程中的核小体合成和切割。我们表明，NSE光谱可以确定域迁移率张量，而域迁移率张量决定了域之间的动态耦合程度。迁移率张量定义了区域速度对施加到它或另一个区域的力的响应，就像帆船的帆在给定的风力下确定其速度一样。NSE结果提供了对蛋白质结构域运动本质的深入了解，而传统生物物理技术无法理解这一点。
Long-range conformational changes in proteins are ubiquitous in biology for the transmission and amplification of signals; such conformational changes can be triggered by small-amplitude, nanosecond protein domain motion. Understanding how conformational changes are initiated requires the characterization of protein domain motion on these timescales and on length scales comparable to protein dimensions. Using neutron spin-echo spectroscopy (NSE), normal mode analysis, and a statistical-mechanical framework, we reveal overdamped, coupled domain motion within DNA polymerase I from Thermus aquaticus (Taq polymerase). This protein utilizes correlated domain dynamics over 70 angstrom to coordinate nucleoticle synthesis and cleavage during DNA synthesis and repair. We show that NSE spectroscopy can determine the domain mobility tensor, which determines the degree of dynamical coupling between domains. The mobility tensor defines the domain velocity response to a force applied to it or to another domain, just as the sails of a sailboat determine its velocity given the applied wind force. The NSE results provide insights into the nature of protein domain motion that are not appreciated by conventional biophysical techniques.