Crystal structure of RecBCD enzyme reveals a machine for processing DNA breaks

RecBCD is a multi-functional enzyme complex that processes DNA ends resulting from a double-strand break. RecBCD is a bipolar helicase that splits the duplex into its component strands and digests them until encountering a recombinational hotspot (Chi site). The nuclease activity is then attenuated...

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Bibliographic Details
Published in:Nature 2004-11, Vol.432 (7014), p.187-193
Main Authors: Wigley, Dale B, Singleton, Martin R, Dillingham, Mark S, Gaudier, Martin, Kowalczykowski, Stephen C
Format: Article
Language:English
Subjects:
Biological and medical sciences
Crystal structure
Crystalline structure
Crystallization
Crystallography, X-Ray
Deoxyribonucleic acid
DNA
DNA - chemistry
DNA - genetics
DNA - metabolism
DNA Damage
DNA Helicases - chemistry
DNA Helicases - metabolism
DNA Repair
Endonucleases - chemistry
Endonucleases - metabolism
Enzymes
Escherichia coli - enzymology
Exodeoxyribonuclease V - chemistry
Exodeoxyribonuclease V - metabolism
Fundamental and applied biological sciences. Psychology
Genetics
Models, Molecular
Molecular biophysics
Multienzyme Complexes - chemistry
Multienzyme Complexes - metabolism
Nucleic Acid Conformation
Protein Conformation
Structure in molecular biology
Structure-Activity Relationship
Substrate Specificity
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Summary:RecBCD is a multi-functional enzyme complex that processes DNA ends resulting from a double-strand break. RecBCD is a bipolar helicase that splits the duplex into its component strands and digests them until encountering a recombinational hotspot (Chi site). The nuclease activity is then attenuated and RecBCD loads RecA onto the 3' tail of the DNA. Here we present the crystal structure of RecBCD bound to a DNA substrate. In this initiation complex, the DNA duplex has been split across the RecC subunit to create a fork with the separated strands each heading towards different helicase motor subunits. The strands pass along tunnels within the complex, both emerging adjacent to the nuclease domain of RecB. Passage of the 3' tail through one of these tunnels provides a mechanism for the recognition of a Chi sequence by RecC within the context of double-stranded DNA. Gating of this tunnel suggests how nuclease activity might be regulated.
ISSN:0028-0836
1476-4687
DOI:10.1038/nature02988