Real-time detection of condensin-driven DNA compaction reveals a multistep binding mechanism.
Real-time detection of condensin-driven DNA compaction reveals a multistep binding mechanism.
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DOI：
10.15252/embj.201797596
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发表时间：
2017-12-01
期刊：
影响因子：
--
通讯作者：
Dekker C
中科院分区：
文献类型：
--
作者：
Eeftens JM;Bisht S;Kerssemakers J;Kschonsak M;Haering CH;Dekker C
凝缩蛋白是环状多亚基蛋白复合物 SMC 蛋白家族的保守成员，对于构建和压缩染色体至关重要。尽管它发挥着关键作用，但其分子机制仍然很大程度上未知。在这里，我们使用单分子磁性镊子实时测量出芽酵母凝缩蛋白复合物对单个 DNA 分子的压缩。我们证明压缩可以大步进行，驱动 DNA 分子在高达 2 pN 的力下进入完全压缩状态。通过施加强力或添加高离子强度的缓冲液可以逆转压实。虽然凝缩蛋白可以在没有 ATP 的情况下稳定地结合 DNA，但需要 SMC 亚基进行 ATP 水解才能使缔合盐不敏感以及随后的压缩过程。我们的结果表明，凝缩素反应循环涉及两个不同的步骤，其中凝缩素首先通过静电相互作用结合DNA，然后使用ATP水解将DNA拓扑包围在其环状结构内，从而启动DNA压缩。两种结合模式对其 DNA 压缩活性至关重要，这一发现对于理解染色体压缩机制具有重要意义。
Condensin, a conserved member of the SMC protein family of ring‐shaped multi‐subunit protein complexes, is essential for structuring and compacting chromosomes. Despite its key role, its molecular mechanism has remained largely unknown. Here, we employ single‐molecule magnetic tweezers to measure, in real time, the compaction of individual DNA molecules by the budding yeast condensin complex. We show that compaction can proceed in large steps, driving DNA molecules into a fully condensed state against forces of up to 2 pN. Compaction can be reversed by applying high forces or adding buffer of high ionic strength. While condensin can stably bind DNA in the absence of ATP, ATP hydrolysis by the SMC subunits is required for rendering the association salt insensitive and for the subsequent compaction process. Our results indicate that the condensin reaction cycle involves two distinct steps, where condensin first binds DNA through electrostatic interactions before using ATP hydrolysis to encircle the DNA topologically within its ring structure, which initiates DNA compaction. The finding that both binding modes are essential for its DNA compaction activity has important implications for understanding the mechanism of chromosome compaction.
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DOI：
10.1083/jcb.200111002
发表时间：
2002-02-04
期刊：
The Journal of cell biology
影响因子：
--
作者：
Anderson DE;Losada A;Erickson HP;Hirano T
通讯作者：
Hirano T
影响因子：
64.5
作者：
Kimura, K;Hirano, T
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影响因子：
64.8
作者：
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通讯作者：
Dogterom, Marileen
DOI：
10.1073/pnas.0700333104
发表时间：
2007-07-17
影响因子：
11.1
作者：
Crut, Aurlien;Koster, Daniel A.;Dekker, Nynke H.
通讯作者：
Dekker, Nynke H.
影响因子：
3.7
作者：
De Vlaminck I;Henighan T;van Loenhout MT;Burnham DR;Dekker C
通讯作者：
Dekker C