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Functionally important movements in RecA molecules and filaments: studies involving mutation and environmental changes

Prabu, Rajan J and Manjunath, GP and Chandra, Nagasuma R and Muniyappa, K and Vijayan, M (2008) Functionally important movements in RecA molecules and filaments: studies involving mutation and environmental changes. In: Acta Crystallographica Section D - Biological Crystallography, 64 (Part 1). pp. 1146-1157.


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The crystal structures of mutants of Mycobacterium smegmatis RecA (MsRecA) involving changes of Gln196 from glutamine to alanine, asparagine and glutamic acid, wild-type MsRecA and several of their nucleotide complexes have been determined using mostly low-temperature and partly room-temperature X-ray data. At both temperatures, nucleotide binding results in a movement of Gln196 towards the bound nucleotide in the wild-type protein. This movement is abolished in the mutants, thus establishing the structural basis for the triggering action of the residue in terms of the size, shape and the chemical nature of the side chain. The 19 crystal structures reported here, together with 11 previously reported MsRecA structures, provide further elaboration of the relation between the pitch of the `inactive' RecA filament, the orientation of the C-terminal domain with respect to the main domain and the location of the switch residue. The low-temperature structures define one extreme of the range of positions the C-terminal domain can occupy. The movement of the C-terminal domain is correlated with those of the LexA-binding loop and the loop that connects the main and the N-terminal domains. These elements of molecular plasticity are made use of in the transition to the `active' filament, as evidenced by the recently reported structures of RecA-DNA complexes. The available structures of RecA resulting from X-ray and electron-microscopic studies appear to represent different stages in the trajectory of the allosteric transformations of the RecA filament. The work reported here contributes to the description of the early stages of this trajectory and provides insight into structures relevant to the later stages.

Item Type: Journal Article
Publication: Acta Crystallographica Section D - Biological Crystallography
Publisher: Blackwell Publishing
Additional Information: Copyright of this article belongs to Blackwell Publishing.
Keywords: RecA;mutations;allosteric transformations.
Department/Centre: Division of Biological Sciences > Molecular Biophysics Unit
Division of Interdisciplinary Sciences > Supercomputer Education & Research Centre
Division of Biological Sciences > Biochemistry
Division of Information Sciences (Doesn't exist now) > BioInformatics Centre
Date Deposited: 03 Jul 2009 11:33
Last Modified: 02 Aug 2012 05:40
URI: http://eprints.iisc.ac.in/id/eprint/16778

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