2crx

From Proteopedia

Revision as of 16:09, 5 November 2007

STRUCTURE OF THE HOLLIDAY JUNCTION INTERMEDIATE IN CRE-LOXP SITE-SPECIFIC RECOMBINATION

Overview

We have determined the X-ray crystal structures of two DNA Holliday, junctions (HJs) bound by Cre recombinase. The HJ is a four-way branched, structure that occurs as an intermediate in genetic recombination, pathways, including site-specific recombination by the lambda-integrase, family. Cre recombinase is an integrase family member that recombines 34, bp loxP sites in the absence of accessory proteins or auxiliary DNA, sequences. The 2.7 A structure of Cre recombinase bound to an immobile HJ, and the 2.5 A structure of Cre recombinase bound to a symmetric, nicked HJ, reveal a nearly planar, twofold-symmetric DNA intermediate that shares, features with both the stacked-X and the square conformations of the HJ, that exist in the unbound state. The structures support a protein-mediated, crossover isomerization of the junction that acts as the switch, responsible for activation and deactivation of recombinase active sites., In this model, a subtle isomerization of the Cre recombinase-HJ quaternary, structure dictates which strands are cleaved during resolution of the, junction via a mechanism that involves neither branch migration nor, helical restacking.

About this Structure

2CRX is a Single protein structure of sequence from Bacteriophage p1. Structure known Active Sites: CIA and CIB. Full crystallographic information is available from OCA.

Reference

Structure of the Holliday junction intermediate in Cre-loxP site-specific recombination., Gopaul DN, Guo F, Van Duyne GD, EMBO J. 1998 Jul 15;17(14):4175-87. PMID:9670032

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