Dueber Erin L Cunningham, Corn Jacob E, Bell Stephen D, Berger James M
Miller Institute for Basic Research in Science, 2536 Channing Way 5190, University of California, Berkeley, CA 94720, USA.
Science. 2007 Aug 31;317(5842):1210-3. doi: 10.1126/science.1143690.
The faithful duplication of genetic material depends on essential DNA replication initiation factors. Cellular initiators form higher-order assemblies on replication origins, using adenosine triphosphate (ATP) to locally remodel duplex DNA and facilitate proper loading of synthetic replisomal components. To better understand initiator function, we determined the 3.4 angstrom-resolution structure of an archaeal Cdc6/Orc1 heterodimer bound to origin DNA. The structure demonstrates that, in addition to conventional DNA binding elements, initiators use their AAA+ ATPase domains to recognize origin DNA. Together these interactions establish the polarity of initiator assembly on the origin and induce substantial distortions into origin DNA strands. Biochemical and comparative analyses indicate that AAA+/DNA contacts observed in the structure are dynamic and evolutionarily conserved, suggesting that the complex forms a core component of the basal initiation machinery.
遗传物质的忠实复制依赖于关键的DNA复制起始因子。细胞起始因子在复制起点形成高阶组装体，利用三磷酸腺苷（ATP）对双链DNA进行局部重塑，并促进合成复制体组件的正确加载。为了更好地理解起始因子的功能，我们确定了与起始DNA结合的古细菌Cdc6/Orc1异二聚体的3.4埃分辨率结构。该结构表明，除了传统的DNA结合元件外，起始因子还利用其AAA+ATP酶结构域识别起始DNA。这些相互作用共同确立了起始因子在起点上组装的极性，并使起始DNA链发生显著扭曲。生化和比较分析表明，结构中观察到的AAA+/DNA接触是动态的且在进化上保守，这表明该复合物构成了基础起始机制的核心组件。
