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DNA stretching by bacterial initiators promotes replication origin openingKarl E. Duderstadt,Kevin Chuang & James M. BergerNature 478,209–213(13 October 2011)doi:10.1038/nature10455Many replication initiators form higher-order oligomers that process host replication origins to promote replisome forrmation. In addition to dedicated duplex-DNA-binding domains, cellular initiators possess AAA+ (ATPases associated with various cellular activities) elements that drive functions ranging from protein assembly to origin recognition. In bacteria, the AAA+ domain of the initiator DnaA has been proposed to assist in single-stranded DNA formation during origin melting. Here we show crystallographically and in solution that the ATP-dependent assembly of Aquifex aeolicus DnaA into a spiral oligomer creates a continuous surface that allows successive AAA+ domains to bind and extend single-stranded DNA segments. The mechanism of binding is unexpectedly similar to that of RecA, a homologous recombination factor, but it differs in that DnaA promotes a nucleic acid conformation that prevents pairing of a complementary strand. These findings, combined with strand-displacement assays, indicate that DnaA opens replication origins by a direct ATP-dependent stretching mechanism. Comparative studies reveal notable commonalities between the approach used by DnaA to engage DNA substrates and other, nucleic-acid-dependent, AAA+ systems.
【序号】1【作者】Tokola, T.; Sarkeala, J.; van der Lin, M.【题目】Use of topographic correction in Landsat TM-based forest interpretation in Nepal【期刊页码】Interna. J.Remote Sens., 2001, 22 (4), pp 551-563【链接】http://www.tandfonline.com/doi/abs/10.1080/01431160050505856
请教大家,难道现在CNAS也配备了资料查重系统?实验室刚建立CNAS体系时,肯定是参考别人家的模板,在提交申请资料时,什么情况被判定是雷同呢?仅仅是体系文件的雷同吗?这样的话,质量手册首先就雷同一大片。