2ief | pdb_00002ief

Structure of the cooperative Excisionase (Xis)-DNA complex reveals a micronucleoprotein filament

spinqualitylabelsall models 2ief, resolution 2.60Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2ief is a 6 chain structure with sequence from Bacteriophage lambda. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Gene: Xis (Bacteriophage lambda) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [VXIS_LAMBD] Excisionase and integrase are necessary for the excision of prophage from the host genome by site-specific recombination at the att site. Publication Abstract from PubMed The DNA architectural protein Xis regulates the construction of higher-order nucleoprotein intasomes that integrate and excise the genome of phage lambda from the Escherichia coli chromosome. Xis modulates the directionality of site-specific recombination by stimulating phage excision 10(6)-fold, while simultaneously inhibiting phage reintegration. Control is exerted by cooperatively assembling onto a approximately 35-bp DNA regulatory element, which it distorts to preferentially stabilize an excisive intasome. Here, we report the 2.6-A crystal structure of the complex between three cooperatively bound Xis proteins and a 33-bp DNA containing the regulatory element. Xis binds DNA in a head-to-tail orientation to generate a micronucleoprotein filament. Although each protomer is anchored to the duplex by a similar set of nonbase specific contacts, malleable protein-DNA interactions enable binding to sites that differ in nucleotide sequence. Proteins at the ends of the duplex sequence specifically recognize similar binding sites and participate in cooperative binding via protein-protein interactions with a bridging Xis protomer that is bound in a less specific manner. Formation of this polymer introduces approximately 72 degrees of curvature into the DNA with slight positive writhe, which functions to connect disparate segments of DNA bridged by integrase within the excisive intasome. Structure of the cooperative Xis-DNA complex reveals a micronucleoprotein filament that regulates phage lambda intasome assembly.,Abbani MA, Papagiannis CV, Sam MD, Cascio D, Johnson RC, Clubb RT Proc Natl Acad Sci U S A. 2007 Feb 13;104(7):2109-14. Epub 2007 Feb 7. PMID:17287355 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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