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

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

Research output: Contribution to journalArticle

124 Citations (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)437-444
Number of pages8
JournalTrends in Biochemical Sciences
Volume30
Issue number8
DOIs
Publication statusPublished - Jan 1 2005
Externally publishedYes

Fingerprint

Minichromosome Maintenance Proteins
Pumps
Single-Stranded DNA
Eukaryota
Adenosine Triphosphatases
DNA
Enzymes
Proteins

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology

Cite this

Pumps, paradoxes and ploughshares : Mechanism of the MCM2-7 DNA helicase. / Takahashi, Tatsuro; Wigley, Dale B.; Walter, Johannes C.

In: Trends in Biochemical Sciences, Vol. 30, No. 8, 01.01.2005, p. 437-444.

Research output: Contribution to journalArticle

Takahashi, Tatsuro ; Wigley, Dale B. ; Walter, Johannes C. / Pumps, paradoxes and ploughshares : Mechanism of the MCM2-7 DNA helicase. In: Trends in Biochemical Sciences. 2005 ; Vol. 30, No. 8. pp. 437-444.
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