Crystal structure of the complete core of archaeal signal recognition particle and implications for interdomain communication
Crystal structure of the complete core of archaeal signal recognition particle and implications for interdomain communication
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DOI：
10.1073/pnas.2436132100
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发表时间：
2003-12-09
影响因子：
11.1
通讯作者：
Sinning, L
中科院分区：
文献类型：
--
作者：
Rosendal, KR;Wild, K;Sinning, L
信号识别颗粒(SRP)对分泌和膜蛋白的靶向在进化上是保守的，而多结构域蛋白SRP54在SRP介导的蛋白质运输中起着关键作用。信号肽与核糖体上SRP54的结合与GTP结合以及随后与SRP受体的复合体形成相协调。由于这些功能局限于SRP54的不同域，因此它们之间的通信至关重要。我们报道了具有和不具有同源SRP RNA结合位点(螺旋8)的来自Archaeon Sulfolobus solfararicus的SRP54的晶体结构。这两种结构显示了SRP核心的灵活性和SRP54相对于RNA的位置。GTPase(G结构域)与信号肽结合(M)结构域之间有一个长连接螺旋，N和M结构域之间的疏水接触将信号肽结合部位与G结构域联系在一起。铰链区位于G和M结构域之间的连接区(292-LGMGD)和M结构域的N-末端部分，允许SRP54在核糖体上结合信号肽时进行结构重排。
Targeting of secretory and membrane proteins by the signal recognition particle (SRP) is evolutionarily conserved, and the multidomain protein SRP54 acts as the key player in SRP-mediated protein transport. Binding of a signal peptide to SRP54 at the ribosome is coordinated with GTP binding and subsequent complex formation with the SRP receptor. Because these functions are localized to distinct domains of SRP54, communication between them is essential. We report the crystal structures of SRP54 from the Archaeon Sulfolobus solfataricus with and without its cognate SRP RNA binding site (helix 8) at 4-Angstrom resolution. The two structures show the flexibility of the SRP core and the position of SRP54 relative to the RNA. A long linker helix connects the GTPase (G domain) with the signal peptide binding (M) domain, and a hydrophobic contact between the N and M domains relates the signal peptide binding site to the G domain. Hinge regions are identified in the linker between the G and M domains (292-LGMGD) and in the N-terminal part of the M domain, which allow for structural rearrangements within SRP54 upon signal peptide binding at the ribosome.