Structural homology between the Rap30 DNA-binding domain and linker histone H5: Implications for preinitiation complex assembly
Structural homology between the Rap30 DNA-binding domain and linker histone H5: Implications for preinitiation complex assembly
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DOI：
10.1073/pnas.95.16.9117
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发表时间：
1998-08-04
影响因子：
11.1
通讯作者：
Werner, MH
中科院分区：
文献类型：
--
作者：
Groft, CM;Uljon, SN;Werner, MH
利用多核核磁共振波谱对人Rap30DNA结合域的三维结构进行了解析。该球形结构域的结构与连接子组蛋白H5的结构非常相似，它的折叠使Rap30进入真核转录因子的“有翼”螺旋-转弯螺旋家族，尽管该结构域与DNA相互作用很弱，但结合表面被发现并与HNF-3/Fork Head-DNA复合体的结构一致。Rap30 DNA结合域的结构对Rap30在组装预引发复合体中的功能具有重要意义。与连接子组蛋白在染色质形成中的功能类似，Rap30DNA结合域的折叠表明它在转录启动中的作用可能是一个凝聚因子，用于预启动复合体的组装。与连接子组蛋白的功能相似性可能解释了Rap30结合依赖于TATA盒结合蛋白诱导的弯曲DNA环境。RAP30 DNA结合区与大肠杆菌Sigma(70)第4区之间的隐蔽序列同源性和功能同源性可能表明，Sigma因子在形成原核闭合复合体的过程中也具有连接物组蛋白样活性。
The three-dimensional structure of the human Rap30 DNA-binding domain has been solved by multinuclear NMR spectroscopy. The structure of the globular domain is strikingly similar to that of linker histone H5 and its fold places Rap30 into the "winged" helix-turn-helix family of eukaryotic transcription factors, Although the domain interacts weakly with DNA, the binding surface was identified and shown to be consistent with the structure of the HNF-3/fork head-DNA complex. The architecture of the Rap30 DNA-binding domain has important implications for the function of Rap30 in the assembly of the preinitiation complex. In analogy to the function of linker histones in chromatin formation, the fold of the Rap30 DNA-binding domain suggests that its role in transcription initiation may be that of a condensation factor for preinitiation complex assembly. Functional similarity to linker histones may explain the dependence of Rap30 binding on the bent DNA environment induced by the TATA box-binding protein. Cryptic sequence identity and functional homology between the Rap30 DNA-binding domain and region 4 of Escherichia coli sigma(70) may indicate that the sigma factors also possess a linker histone-like activity in the formation of a prokaryotic closed complex.