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Registro de acceso abierto Molecular architecture of a multifunctional MCM complex

Autor :Sánchez-Berrondo, June
Mesa, Pablo
Ibarra, Arkaitz
Martínez-Jiménez, Maria I.
Blanco, Luis
Méndez, Juan
Boskovic, Jasminka
Montoya, Guillermo
Palabras clave :Bacillus cereus, DNA replication, MCM complex
Fecha de publicación :7-oct-2011
Editor:Oxford University Press
Citación :Nucleic Acids Research 40 (3): 1366-1380 (2012)
Resumen:DNA replication is strictly regulated through a sequence of steps that involve many macromolecular protein complexes. One of them is the replicative helicase, which is required for initiation and elongation phases. A MCM helicase found as a prophage in the genome of Bacillus cereus is fused with a primase domain constituting an integrative arrangement of two essential activities for replication. We have isolated this helicase–primase complex (BcMCM) showing that it can bind DNA and displays not only helicase and primase but also DNA polymerase activity. Using single-particle electron microscopy and 3D reconstruction, we obtained structures of BcMCM using ATPγS or ADP in the absence and presence of DNA. The complex depicts the typical hexameric ring shape. The dissection of the unwinding mechanism using site-directed mutagenesis in the Walker A, Walker B, arginine finger and the helicase channels, suggests that the BcMCM complex unwinds DNA following the extrusion model similarly to the E1 helicase from papillomavirus.
Descripción :Disponible material suplementario
Versión del editor:http://dx.doi.org/10.1093/nar/gkr831
URI :http://hdl.handle.net/10261/57334
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