ATP-dependent positive supercoiling of DNA by 13S condensin: A biochemical implication for chromosome condensation
ATP-dependent positive supercoiling of DNA by 13S condensin: A biochemical implication for chromosome condensation
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DOI：
10.1016/s0092-8674(00)80524-3
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发表时间：
1997-08-22
期刊：
影响因子：
64.5
通讯作者：
Hirano, T
中科院分区：
文献类型：
--
作者：
Kimura, K;Hirano, T
13 S凝聚素是一种五亚基蛋白复合物，在非洲爪蟾卵提取物的有丝分裂染色体凝聚中起核心作用。该复合物的两个核心亚基XCAP-C和XCAP-E属于一个新兴的推定ATP酶家族，即SMC家族。我们在这里报告，13 S凝聚素具有DNA刺激的ATP酶活性，并表现出高亲和力的结构DNA，如十字形DNA。13 S凝聚素在细菌或真核生物拓扑异构酶I存在下能够将正超螺旋引入闭合环状DNA中。超螺旋反应是ATP依赖性的。我们认为，13 S缩合素通过利用ATP水解的能量以右手方向包裹DNA。这种反应可能代表了有丝分裂过程中染色质纤维致密化的关键机制。
13S condensin is a five-subunit protein complex that plays a central role in mitotic chromosome condensation in Xenopus egg extracts. Two core subunits of this complex, XCAP-C and XCAP-E, belong to an emerging family of putative ATPases, the SMC family. We report here that 13S condensin has a DNA-stimulated ATPase activity and exhibits a high affinity for structured DNAs such as cruciform DNA. 13S condensin is able to introduce positive supercoils into a closed circular DNA in the presence of bacterial or eukaryotic topoisomerase I. The supercoiling reaction is ATP-dependent. We propose that 13S condensin wraps DNA in a right-handed direction by utilizing the energy of ATP hydrolysis. This reaction may represent a key mechanism underlying the compaction of chromatin fibers during mitosis.