RecBCD enzyme and the repair of double-stranded DNA breaks

Mark S Dillingham, Stephen C Kowalczykowski

Research output: Contribution to journalArticle (Academic Journal)peer-review

421 Citations (Scopus)


The RecBCD enzyme of Escherichia coli is a helicase-nuclease that initiates the repair of double-stranded DNA breaks by homologous recombination. It also degrades linear double-stranded DNA, protecting the bacteria from phages and extraneous chromosomal DNA. The RecBCD enzyme is, however, regulated by a cis-acting DNA sequence known as Chi (crossover hotspot instigator) that activates its recombination-promoting functions. Interaction with Chi causes an attenuation of the RecBCD enzyme's vigorous nuclease activity, switches the polarity of the attenuated nuclease activity to the 5' strand, changes the operation of its motor subunits, and instructs the enzyme to begin loading the RecA protein onto the resultant Chi-containing single-stranded DNA. This enzyme is a prototypical example of a molecular machine: the protein architecture incorporates several autonomous functional domains that interact with each other to produce a complex, sequence-regulated, DNA-processing machine. In this review, we discuss the biochemical mechanism of the RecBCD enzyme with particular emphasis on new developments relating to the enzyme's structure and DNA translocation mechanism.
Translated title of the contributionRecBCD Enzyme and the repair of double-stranded DNA breaks
Original languageEnglish
Pages (from-to)642-71, Table of Contents
Number of pages30
JournalMicrobiology and Molecular Biology Reviews
Issue number4
Publication statusPublished - Dec 2008


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