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Archaea
Volume 2010, Article ID 505693, 8 pages
http://dx.doi.org/10.1155/2010/505693
Research Article

Different Residues on the Surface of the Methanothermobacter thermautotrophicus MCM Helicase Interact with Single- and Double-Stranded DNA

1Center for Advanced Research in Biotechnology, University of Maryland Biotechnology Institute, 9600 Gudelsky Drive, Rockville, MD 20850, USA
2Laboratory of Viral Diseases, NIAID, NIH, 4 Center Drive, Bethesda, MD 20892, USA
3Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, 111 TW Alexander Drive, Research Triangle Park, NC 27709, USA
4Department of Cell Biology and Molecular Genetics, Institute for Bioscience and Biotechnology Research, University of Maryland, 9600 Gudelsky Drive, Rockville, MD 20850, USA

Received 5 August 2010; Accepted 16 October 2010

Academic Editor: Y. Ishino

Copyright © 2010 Nozomi Sakakibara et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The minichromosome maintenance (MCM) complex is thought to function as the replicative helicase in archaea, separating the two strands of chromosomal DNA during replication. The catalytic activity resides within the C-terminal region of the MCM protein, while the N-terminal portion plays an important role in DNA binding and protein multimerization. An alignment of MCM homologues from several archaeal species revealed a number of conserved amino acids. Here several of the conserved residues located on the surface of the helicase have been mutated and their roles in MCM functions determined. It was found that some mutations result in increased affinity for ssDNA while the affinity for dsDNA is decreased. Other mutants exhibit the opposite effect. Thus, the data suggest that these conserved surface residues may participate in MCM-DNA interactions.