This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
1drg
From Proteopedia
|
CRYSTAL STRUCTURE OF TRIMERIC CRE RECOMBINASE-LOX COMPLEX
Overview
The crystal structure of a novel Cre-Lox synapse was solved using phases, from multiple isomorphous replacement and anomalous scattering, and, refined to 2.05 A resolution. In this complex, a symmetric protein trimer, is bound to a Y-shaped three-way DNA junction, a marked departure from the, pseudo-4-fold symmetrical tetramer associated with Cre-mediated LoxP, recombination. The three-way DNA junction was accommodated by a simple, kink without significant distortion of the adjoining DNA duplexes., Although the mean angle between DNA arms in the Y and X structures was, similar, adjacent Cre trimer subunits rotated 29 degrees relative to those, in the tetramers. This rotation was accommodated at the protein-protein, and DNA-DNA interfaces by interactions that are "quasi-equivalent" to, those in the tetramer, analogous to packing differences of chemically, identical viral subunits at non-equivalent positions in icosahedral, capsids. This structural quasi-equivalence extends to function as Cre can, bind to, cleave and perform strand transfer with a three-way Lox, substrate. The structure explains the dual recognition of three and, four-way junctions by site-specific recombinases as being due to shared, structural features between the differently branched substrates and, plasticity of the protein-protein interfaces. To our knowledge, this is, the first direct demonstration of quasi-equivalence in both the assembly, and function of an oligomeric enzyme.
About this Structure
1DRG is a Single protein structure of sequence from Enterobacteria phage p21. Full crystallographic information is available from OCA.
Reference
Quasi-equivalence in site-specific recombinase structure and function: crystal structure and activity of trimeric Cre recombinase bound to a three-way Lox DNA junction., Woods KC, Martin SS, Chu VC, Baldwin EP, J Mol Biol. 2001 Oct 12;313(1):49-69. PMID:11601846
Page seeded by OCA on Tue Nov 20 13:31:28 2007
