3C1D

X-ray crystal structure of RecX

Summary for 3C1D

• Entry DOI: 10.2210/pdb3c1d/pdb
• Descriptor: Regulatory protein recX (2 entities in total)
• Functional Keywords: tandem repeats, helix-turn-helix, cytoplasm, dna damage, dna repair, sos response, dna binding protein, recombination
• Biological source: Escherichia coli
• Cellular location: Cytoplasm (Potential): P66000
• Total number of polymer chains: 2
• Total formula weight: 36969.92

Authors

Ragone, S.,Maman, J.D.,Furnham, N.,Pellegrini, L. (deposition date: 2008-01-23, release date: 2008-07-15, Last modification date: 2024-02-21)

Primary citation

Ragone, S.,Maman, J.D.,Furnham, N.,Pellegrini, L.
Structural basis for inhibition of homologous recombination by the RecX protein.
Embo J., 27:2259-2269, 2008

PubMed Abstract: The RecA/RAD51 nucleoprotein filament is central to the reaction of homologous recombination (HR). Filament activity must be tightly regulated in vivo as unrestrained HR can cause genomic instability. Our mechanistic understanding of HR is restricted by lack of structural information about the regulatory proteins that control filament activity. Here, we describe a structural and functional analysis of the HR inhibitor protein RecX and its mode of interaction with the RecA filament. RecX is a modular protein assembled of repeated three-helix motifs. The relative arrangement of the repeats generates an elongated and curved shape that is well suited for binding within the helical groove of the RecA filament. Structure-based mutagenesis confirms that conserved basic residues on the concave side of RecX are important for repression of RecA activity. Analysis of RecA filament dynamics in the presence of RecX shows that RecX actively promotes filament disassembly. Collectively, our data support a model in which RecX binding to the helical groove of the filament causes local dissociation of RecA protomers, leading to filament destabilisation and HR inhibition.

PubMed: 18650935
DOI: 10.1038/emboj.2008.145

Experimental method

X-RAY DIFFRACTION (1.8 Å)