Structure of unliganded GRP94, the endoplasmic reticulum Hsp90 - Basis for nucleotide-induced conformational change
Structure of unliganded GRP94, the endoplasmic reticulum Hsp90 - Basis for nucleotide-induced conformational change
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DOI：
10.1074/jbc.m503761200
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发表时间：
2005-08-26
影响因子：
4.8
通讯作者：
Gewirth, DT
中科院分区：
文献类型：
--
作者：
Dollins, DE;Immormino, RM;Gewirth, DT
GRP 94是Hsp 90的内质网旁体，其N端调控区与腺苷酸结合，调节GRP 94的表达。由于其对核苷酸的弱亲和力，GRP 94中的功能相关转变可能在未配体和核苷酸结合状态之间。我们已经确定了未配体的GRP 94 N-结构域的结构。未配体蛋白的螺旋1-4-5亚结构域采用与抑制剂复合的蛋白结构中所见的闭合构象。这种构象不同于蛋白质与ATP或ADP结合时所见的亚结构域的开放构象。ADP浸泡到晶体的unliganded蛋白质揭示了中间构象之间的开放和封闭状态的中间，并表明在GRP 94的开放和封闭状态之间的转换是由配体结合驱动。GRP 94中观察到的运动方向表明，核苷酸的作用是打开亚结构域元件，而不是关闭它们，这与Hsp 90提出的运动相反。这些观察结果支持一个模型，其中ATP结合决定了N-结构域的构象，并调节其形成四级结构相互作用的能力。
GRP94, the endoplasmic reticulum paralog of Hsp90, is regulated by adenosine nucleotides that bind to its N-terminal regulatory domain. Because of its weak affinity for nucleotides, the functionally relevant transition in GRP94 is likely to be between the unliganded and nucleotide-bound states. We have determined the structure of the unliganded GRP94 N-domain. The helix 1-4-5 subdomain of the unliganded protein adopts the closed conformation seen in the structure of the protein in complex with inhibitors. This conformation is distinct from the open conformation of the subdomain seen when the protein is bound to ATP or ADP. ADP soaked into crystals of the unliganded protein reveals an intermediate conformation midway between the open and closed states and demonstrates that in GRP94 the conversion between the open and closed states is driven by ligand binding. The direction of the observed movement in GRP94 shows that nucleotides act to open the subdomain elements rather than close them, which is contrary to the motion proposed for Hsp90. These observations support a model where ATP binding dictates the conformation of the N-domain and regulates its ability to form quaternary structural interactions.