1f44

<StructureSection load='1f44' size='340' side='right' caption='[[1f44]], [[Resolution|resolution]] 2.05&Aring;' scene=''>

<table><tr><td colspan='2'>[[1f44]] is a 3 chain structure with sequence from [http://en.wikipedia.org/wiki/Bpp1 Bpp1]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1F44 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1F44 FirstGlance]. <br>

</td></tr><tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[1drg|1drg]]</td></tr>

<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">CRE RECOMBINASE ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=10678 BPP1])</td></tr>

<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1f44 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1f44 OCA], [http://pdbe.org/1f44 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1f44 RCSB], [http://www.ebi.ac.uk/pdbsum/1f44 PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=1f44 ProSAT]</span></td></tr>

[[http://www.uniprot.org/uniprot/RECR_BPP1 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.

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== Publication Abstract from PubMed ==

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.

 

== References ==

[[Category: Bpp1]]

[[Category: Baldwin, E P]]

[[Category: Woods, K C]]

[[Category: Branched dna]]

[[Category: Y-junction]]