Structure and function of DnaA N-terminal domains - Specific sites and mechanisms in inter-DnaA interaction and in DnaB helicase loading on oriC
Structure and function of DnaA N-terminal domains - Specific sites and mechanisms in inter-DnaA interaction and in DnaB helicase loading on oriC
复制标题
DOI：
10.1074/jbc.m701841200
复制
发表时间：
2007-06-15
影响因子：
4.8
通讯作者：
Ueda, Tadashi
中科院分区：
文献类型：
--
作者：
Abe, Yoshito;Jo, Takaaki;Ueda, Tadashi
DnaA与染色体复制起点（oriC）形成同源多聚体复合物以解旋双链体DNA。DnaA N末端与DnaB解旋酶的相互作用对于将DnaB装载到解旋区域上是至关重要的。在这里，我们使用NMR确定了DnaA N末端结构。该区域（残基1 - 108）由刚性区域（结构域I）和柔性区域（结构域II）组成。结构域I具有α-α-β-β-α-β基序，类似于K同源（KH）结构域的基序，并且对oriC单链DNA具有弱亲和力，与KH结构域功能一致。携带Trp-6的疏水表面最有可能形成结构域I二聚化的界面。Glu-21位于结构域I与Trp-6位点相对的表面上，对于DnaB解旋酶加载至关重要。这些研究结果表明，DnaA同源多聚体形成和DnaB解旋酶加载oriC的模型。
DnaA forms a homomultimeric complex with the origin of chromosomal replication (oriC) to unwind duplex DNA. The interaction of the DnaA N terminus with the DnaB helicase is crucial for the loading of DnaB onto the unwound region. Here, we determined the DnaA N terminus structure using NMR. This region (residues 1 -108) consists of a rigid region (domain I) and a flexible region (domain II). Domain I has an alpha-alpha-beta-beta-alpha-beta motif, similar to that of the K homology (KH) domain, and has weak affinity for oriC single-stranded DNA, consistent with KH domain function. A hydrophobic surface carrying Trp-6 most likely forms the interface for domain I dimerization. Glu-21 is located on the opposite surface of domain I from the Trp-6 site and is crucial for DnaB helicase loading. These findings suggest a model for DnaA homomultimer formation and DnaB helicase loading on oriC.