Pumps, paradoxes and ploughshares: Mechanism of the MCM2-7 DNA helicase

Tatsuro S. Takahashi, Dale B. Wigley, Johannes C. Walter

研究成果: Contribution to journalArticle査読

126 被引用数 (Scopus)


In eukaryotes, numerous lines of evidence have coalesced into a convincing case that the MCM2-7 complex - a heterohexameric ATPase - is the replicative DNA helicase. However, almost nothing is known about how this enzyme functions in a cellular context. Some models for the mechanism of the MCM2-7 helicase envision that it translocates along single-stranded DNA (ssDNA), whereas, more recently, it is has been suggested that it pumps double-stranded DNA (dsDNA) through its central channel. In particular, one model in which a double hexamer of MCM2-7 pumps dsDNA towards the hexamer interface and extrudes ssDNA laterally as a result of torsional strain is gaining popularity. Here, we discuss existing models and propose a new variation in which a single hexamer is the functional unit of the helicase. Duplex DNA is pumped into MCM2-7 and, as it emerges from the complex, a rigid protein that we term the 'ploughshare' splits the duplex.

ジャーナルTrends in Biochemical Sciences
出版ステータス出版済み - 8 2005

All Science Journal Classification (ASJC) codes

  • 生化学
  • 分子生物学


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