Processive DNA helicase activity of the minichromosome maintenance proteins 4, 6, and 7 complex requires forked DNA structures
AUTOR(ES)
Lee, Joon-Kyu
FONTE
The National Academy of Sciences
RESUMO
The minichromosome maintenance (Mcm) proteins 2–7 are required for both the initiation and elongation steps of chromosomal DNA replication. Previous studies have shown that the Mcm complex consisting of the Mcm 4, 6, and 7 proteins contains 3′ to 5′ DNA helicase activity with limited processivity (displacing duplex DNA regions up to 30 nt). In this report, we show that the presence of both 5′ and 3′ single-stranded tails in DNA helicase substrates is essential for the processive helicase activity of the Mcm complex. The presence of both 5′ and 3′ tails facilitated the formation of double heterohexameric complexes of Mcm4/6/7 on substrate DNA, which appeared to be essential for the processive helicase activity. The double heterohexameric complex of Mcm4/6/7, in the presence of a single-strand DNA binding protein, is capable of unwinding duplex DNA region of about 600 bp in length. These results support the hypothesis that the Mcm4/6/7 complex can function as a replication helicase.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=14543Documentos Relacionados
- The single minichromosome maintenance protein of Methanobacterium thermoautotrophicum ΔH contains DNA helicase activity
- Biochemical Analysis of the Intrinsic Mcm4-Mcm6-Mcm7 DNA Helicase Activity
- Phosphorylation of MCM4 by cdc2 protein kinase inhibits the activity of the minichromosome maintenance complex.
- A double-hexamer archaeal minichromosome maintenance protein is an ATP-dependent DNA helicase
- MINUTES OF THE 20th ANNUAL MEETING HELD AT NEW YORK, JUNE 4, 5, 6, 1917
