Structural and functional analyses of five conserved positively charged residues in the L1 and N-terminal DNA binding motifs of archaeal RADA protein.
Structural and functional analyses of five conserved positively charged residues in the L1 and N-terminal DNA binding motifs of archaeal RADA protein.
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DOI：
10.1371/journal.pone.0000858
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发表时间：
2007-09-12
期刊：
影响因子：
3.7
通讯作者：
Wang TF
中科院分区：
文献类型：
--
作者：
Chen LT;Ko TP;Chang YW;Lin KA;Wang AH;Wang TF
RecA家族蛋白参与ATP依赖性DNA链交换反应，包括ssDNA核蛋白螺旋丝和同源dsDNA序列。尽管经过20多年的努力，同源配对和链交换的分子机制仍然没有完全理解。在这里，我们报告的晶体结构硫磺硫化叶菌RadA过度缠绕右手丝与三个单体每个螺距。该结构揭示了第一ssDNA结合无序环（表示为L1基序）和dsDNA结合N-末端结构域（NTD）的构象细节。L1和NTD一起在螺旋丝的外表面上形成向外张开的手掌结构。在这种棕榈结构内，五个保守的碱性氨基酸残基（K27、K60、R117、R223和R229）围绕一个25 μ m的口袋，该口袋足够宽以容纳阴离子ssDNA、dsDNA或两者。生化分析表明，这五个带正电荷的残基是必不可少的DNA结合和RadA催化的D-环的形成。我们认为，过度缠绕的右手RadA丝代表的同源搜索和配对反应中的功能构象。提出了RadA-ssDNA核蛋白丝与其dsDNA靶之间同源相互作用的一个新的结构模型。
RecA family proteins engage in an ATP-dependent DNA strand exchange reaction that includes a ssDNA nucleoprotein helical filament and a homologous dsDNA sequence. In spite of more than 20 years of efforts, the molecular mechanism of homology pairing and strand exchange is still not fully understood. Here we report a crystal structure of Sulfolobus solfataricus RadA overwound right-handed filament with three monomers per helical pitch. This structure reveals conformational details of the first ssDNA binding disordered loop (denoted L1 motif) and the dsDNA binding N-terminal domain (NTD). L1 and NTD together form an outwardly open palm structure on the outer surface of the helical filament. Inside this palm structure, five conserved basic amino acid residues (K27, K60, R117, R223 and R229) surround a 25 Å pocket that is wide enough to accommodate anionic ssDNA, dsDNA or both. Biochemical analyses demonstrate that these five positively charged residues are essential for DNA binding and for RadA-catalyzed D-loop formation. We suggest that the overwound right-handed RadA filament represents a functional conformation in the homology search and pairing reaction. A new structural model is proposed for the homologous interactions between a RadA-ssDNA nucleoprotein filament and its dsDNA target.
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影响因子：
16.8
作者：
Conway, AB;Lynch, TW;Rice, PA
通讯作者：
Rice, PA
影响因子：
5.6
作者：
Aihara, H;Ito, Y;Shibata, T
通讯作者：
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影响因子：
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作者：
Chen, LW;Haushalter, KA;Verdine, GL
通讯作者：
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影响因子：
10.5
作者：
ROCKMILL, B;SYM, M;ROEDER, GS
通讯作者：
ROEDER, GS
DOI：
10.1016/j.bbrc.2004.08.163
发表时间：
2004-10-22
影响因子：
3.1
作者：
Lee, MH;Leng, CH;Wang, TF
通讯作者：
Wang, TF