%0 Journal Article
%T The N-terminal domain of Escherichia coli RecA have multiple functions in promoting homologous recombination
%A Chien-Der Lee
%A Ting-Fang Wang
%J Journal of Biomedical Science
%D 2009
%I BioMed Central
%R 10.1186/1423-0127-16-37
%X Escherichia coli RecA is the founding member of the RecA protein family. It is essential for the initiation of repair of DNA breaks via homologous recombination, induction of the DNA damage-induced 'SOS' response, and activation of translesion DNA synthesis, as well as development and transmission of antibiotic resistance genes [1,2]. Nearly all known functions of RecA require the formation of a presynaptic helical filament comprised of single-stranded DNA (ssDNA) bound to multiple RecA monomers with ATP. During homologous recombination, this activated form of the helical filament is capable of interacting with homologous double-stranded DNA (dsDNA) to form a heteroduplex DNA molecule. Eventually, the DNA strands are exchanged, resulting in the displacement of one of the original duplex strands and the subsequent creation of a new heteroduplex (or D-loop). This function is evolutionarily conserved in other members of the RecA family, including archaeal RadA and the eukaryotic proteins, Rad51 and Dmc1.The RecA monomer has three major structural domains: a small N-terminal domain (NTD), a core ATPase domain (CAD), and a large C-terminal domain (CTD). By contrast, the monomers of RadA/Rad51/Dmc1 consist of a CAD and a larger NTD. The CAD, often referred to as the RecA fold [3], is structurally similar to the ATPase domains of DNA/RNA helicases, F1 ATPases, chaperone-like ATPases, and membrane transporters [4]. Highly conserved in all RecA family proteins, the CAD contains two disordered loops (denoted the L1 and L2 motifs) that bind to ssDNA and are responsible for ssDNA-stimulated ATPase activity [5]. All RecA family proteins are polymerized via a polymerization motif located between the NTD and the CAD. The polymerization motif contains a hydrophobic residue (isoleucine 26 in E. coli RecA; phenylalanines in RadA, Rad51, and Dmc1) that docks within the hydrophobic pocket of the neighboring CAD. This interaction was also observed at the binding interface between a huma
%U http://www.jbiomedsci.com/content/16/1/37