Shrivastava Indira H, Durell Stewart R, Guy H Robert
Laboratory of Experimental and Computational Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892-5567, USA.
Biophys J. 2004 Oct;87(4):2255-70. doi: 10.1529/biophysj.104.040592.
Having inspected the crystal structure of the complete KvAP channel protein, we suspect that the voltage-sensing domain is too distorted to provide reliable information about its native tertiary structure or its interactions with the central pore-forming domain. On the other hand, a second crystal structure of the isolated voltage-sensing domain may well correspond to a native open conformation. We also observe that the paddle model of gating developed from these two structures is inconsistent with many experimental results, and suspect it to be energetically unrealistic. Here we show that the isolated voltage-sensing domain crystal structure can be docked onto the pore domain portion of the full-length KvAP crystal structure in an energetically favorable way to create a model of the open conformation. Using this as a starting point, we have developed rather conventional models of resting and transition conformations based on the helical screw mechanism for the transition from the open to the resting conformation. Our models are consistent with both theoretical considerations and experimental results.
在检查了完整的KvAP通道蛋白的晶体结构后,我们怀疑电压感应结构域扭曲过度,无法提供有关其天然三级结构或其与中央孔形成结构域相互作用的可靠信息。另一方面,分离的电压感应结构域的第二个晶体结构很可能对应于天然开放构象。我们还观察到,从这两个结构发展而来的门控桨状模型与许多实验结果不一致,并怀疑其在能量上不现实。在这里,我们表明,分离的电压感应结构域晶体结构可以以能量有利的方式对接至全长KvAP晶体结构的孔结构域部分,以创建开放构象模型。以此为起点,我们基于从开放构象到静息构象转变的螺旋机制,开发了相当传统的静息和转变构象模型。我们的模型与理论考量和实验结果均一致。