Structural and functional analyses of five conserved positively charged residues in the L1 and N-terminal DNA binding motifs of archaeal RadA protein

Li Tzu Chen, Tzu Ping Ko, Yu Wei Chang, Kuei An Lin, Andrew H.J. Wang, Ting Fang Wang

研究成果: 雜誌貢獻文章同行評審

18 引文 斯高帕斯(Scopus)

摘要

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 Sulfblobus 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 conserveq 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 matter proposed for the homologous interactions between a RadA-ssDNA nucleoprotein filament and its dsDNA target.

原文英語
文章編號e858
期刊PLoS ONE
2
發行號9
DOIs
出版狀態已發佈 - 9月 12 2007
對外發佈

ASJC Scopus subject areas

  • 多學科

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