Bacterial chromosome segregation:: structure and DNA binding of the Soj dimer -: a conserved biological switch
Bacterial chromosome segregation:: structure and DNA binding of the Soj dimer -: a conserved biological switch
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DOI：
10.1038/sj.emboj.7600530
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发表时间：
2005-01-26
期刊：
影响因子：
11.4
通讯作者：
Löwe, J
中科院分区：
文献类型：
--
作者：
Leonard, TA;Butler, PJ;Löwe, J
革兰氏阴性嗜热菌SOJ和Spo0J属于保守的Parab细菌蛋白家族，参与了质粒和染色体的分裂。Spo0J与复制起点附近的DNA结合，并在复制开始后定位于两极。SOJ在类核区域以依赖于ATP和Spo0J的方式振荡。在这里，我们证明了SOJ在溶液中经历了依赖于ATP的二聚反应，并与DNA形成核蛋白细丝。SOJ在三个核苷酸状态下的晶体结构表明，空态和ADP结合态是单体，而一个缺乏水解的突变体D44A能够形成核苷酸“三明治”二聚体。Spo0J或Spo0J的N-末端20个氨基酸可刺激SOJ-ATPase活性。我们的分析表明，包含Lys/Arg的多肽的二聚化和激活分别对于SOJ、Para和Mind及其调节剂Spo0J、PARB和Mine是保守的。通过与固氮酶铁蛋白和GTP酶FFH/FtsY的同源性，我们认为SOJ的二聚化和调节代表了一种保守的生物开关。
Soj and Spo0J of the Gram-negative hyperthermophile Thermus thermophilus belong to the conserved ParAB family of bacterial proteins implicated in plasmid and chromosome partitioning. Spo0J binds to DNA near the replication origin and localises at the poles following initiation of replication. Soj oscillates in the nucleoid region in an ATP- and Spo0J-dependent fashion. Here, we show that Soj undergoes ATP-dependent dimerisation in solution and forms nucleoprotein filaments with DNA. Crystal structures of Soj in three nucleotide states demonstrate that the empty and ADP-bound states are monomeric, while a hydrolysis-deficient mutant, D44A, is capable of forming a nucleotide 'sandwich' dimer. Soj ATPase activity is stimulated by Spo0J or the N-terminal 20 amino-acid peptide of Spo0J. Our analysis shows that dimerisation and activation involving a peptide containing a Lys/Arg is conserved for Soj, ParA and MinD and their modulators Spo0J, ParB and MinE, respectively. By homology to the nitrogenase iron protein and the GTPases Ffh/FtsY, we suggest that Soj dimerisation and regulation represent a conserved biological switch.