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The mechanism of asymmetric strand exchange in Cre‐loxP site‐specific recombination
Author(s) -
Van Duyne Gregory,
Ghosh Kaushik
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a44-b
Subject(s) - synapsis , antiparallel (mathematics) , recombinase , cre recombinase , recombination , site specific recombination , holliday junction , dna , recombinant dna , chemistry , cleavage (geology) , crossover , biophysics , biology , stereochemistry , biochemistry , physics , gene , paleontology , transgene , genetically modified mouse , quantum mechanics , artificial intelligence , fracture (geology) , magnetic field , computer science
Cre recombinase catalyzes the sequential exchange of DNA strands between 34‐bp loxP sites to form recombinant products in a variety of topological contexts. Biochemical evidence indicates that the reaction is strongly asymmetric; one pair of strands is preferentially exchanged to form a Holliday junction intermediate and the remaining pair of strands is preferentially resolved to form recombinant products. We have identified the structural and biochemical basis for the asymmetric nature of this recombination reaction using a combination of X‐ray crystallographic models, assays developed to study synapsis of loxP sites in solution, cleavage of 5′‐bridging phosphorothioate‐containing substrates, and FRET experiments designed to distinguish between alternative synaptic configurations. The experimental data strongly support a model in which formation of a preferred synaptic complex dictates the order of strand exchanges. The loxP crossover sequence appears to have been fine‐tuned to provide productive antiparallel synapsis of sites as well as an efficient pathway for ordered strand exchange.