1q3u
From Proteopedia
Crystal structure of a wild-type Cre recombinase-loxP synapse: pre-cleavage complex
Structural highlights
Function[RECR_BPP1] Catalyzes site-specific recombination between two 34-base-pair LOXP sites. Its role is to maintain the phage genome as a monomeric unit-copy plasmid in the lysogenic state. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedEscherichia coli phage P1 Cre recombinase catalyzes the site-specific recombination of DNA containing loxP sites. We report here two crystal structures of a wild-type Cre recombinase-loxP synaptic complex corresponding to two distinct reaction states: an initial pre-cleavage complex, trapped using a phosphorothioate modification at the cleavable scissile bond that prevents the recombination reaction, and a 3'-phosphotyrosine protein-DNA intermediate resulting from the first strand cleavage. In contrast to previously determined Cre complexes, both structures contain a full tetrameric complex in the asymmetric unit, unequivocally showing that the anti-parallel arrangement of the loxP sites is an intrinsic property of the Cre-loxP recombination synapse. The conformation of the spacer is different to the one observed for the symmetrized loxS site: a kink next to the scissile phosphate in the top strand of the pre-cleavage complex leads to unstacking of the TpG step and a widening of the minor groove. This side of the spacer is interacting with a 'cleavage-competent' Cre subunit, suggesting that the first cleavage occurs at the ApT step in the top strand. This is further confirmed by the structure of the 3'-phosphotyrosine intermediate, where the DNA is cleaved in the top strands and covalently linked to the 'cleavage-competent' subunits. The cleavage is followed by a movement of the C-terminal part containing the attacking Y324 and the helix N interacting with the 'non-cleaving' subunit. This rearrangement could be responsible for the interconversion of Cre subunits. Our results also suggest that the Cre-induced kink next to the scissile phosphodiester activates the DNA for cleavage at this position and facilitates strand transfer. Crystal structure of a wild-type Cre recombinase-loxP synapse reveals a novel spacer conformation suggesting an alternative mechanism for DNA cleavage activation.,Ennifar E, Meyer JE, Buchholz F, Stewart AF, Suck D Nucleic Acids Res. 2003 Sep 15;31(18):5449-60. PMID:12954782[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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