Narrowing the conformational space sampled by two-domain proteins with paramagnetic probes in both domains
Narrowing the conformational space sampled by two-domain proteins with paramagnetic probes in both domains
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DOI：
10.1007/s10858-011-9532-2
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发表时间：
2011-11-01
影响因子：
2.7
通讯作者：
Ubbink, Marcellus
中科院分区：
文献类型：
--
作者：
Dasgupta, Soumyasri;Hu, Xiaoyu;Ubbink, Marcellus
钙调蛋白是一种具有两个结构域的蛋白质，在溶液中，当其结构域发生重新定位时，可以采用多种构象。根据基于顺磁性的限制条件，计算了一组代表蛋白质可能采样的整体构象空间的钙调蛋白构象的最大出现次数(MO)。在C-末端结构域中加入稀土结合标签后，测量了这些限制因素，以补充通过将三个顺磁性稀土离子取代N-末端结构域第二个钙结合环中的钙离子而获得的数据。分析表明，金属离子在两个结构域上产生的顺磁约束的可用性，不同程度地降低了构象的分子轨道，从而有助于识别那些可以被蛋白质采样的构象。
Calmodulin is a two-domain protein which in solution can adopt a variety of conformations upon reorientation of its domains. The maximum occurrence (MO) of a set of calmodulin conformations that are representative of the overall conformational space possibly sampled by the protein, has been calculated from the paramagnetism-based restraints. These restraints were measured after inclusion of a lanthanide binding tag in the C-terminal domain to supplement the data obtained by substitution of three paramagnetic lanthanide ions to the calcium ion in the second calcium binding loop of the N-terminal domain. The analysis shows that the availability of paramagnetic restraints arising from metal ions placed on both domains, reduces the MO of the conformations to different extents, thereby helping to identify those conformations that can be mostly sampled by the protein.