1RH6

Bacteriophage Lambda Excisionase (Xis)-DNA Complex

Summary for 1RH6

• Entry DOI: 10.2210/pdb1rh6/pdb
• Descriptor: 5'-D(*CP*TP*AP*TP*GP*TP*AP*GP*TP*CP*TP*GP*TP*TP*G)-3', 5'-D(P*CP*AP*AP*CP*AP*GP*AP*CP*TP*AP*CP*AP*TP*AP*G)-3', Excisionase, ... (4 entities in total)
• Functional Keywords: protein-dna complex, dna architectural protein, 'winged'-helix protein, phage excision, site-specific dna recombination, dna binding protein-dna complex, dna binding protein/dna
• Biological source: Enterobacteria phage lambda
• Total number of polymer chains: 4
• Total formula weight: 22764.61

Authors

Sam, M.D.,Cascio, D.,Johnson, R.C.,Clubb, R.T. (deposition date: 2003-11-13, release date: 2004-06-29, Last modification date: 2024-02-14)

Primary citation

Sam, M.D.,Cascio, D.,Johnson, R.C.,Clubb, R.T.
Crystal structure of the excisionase-DNA complex from bacteriophage lambda.
J.Mol.Biol., 338:229-240, 2004

PubMed Abstract: The excisionase (Xis) protein from bacteriophage lambda is the best characterized member of a large family of recombination directionality factors that control integrase-mediated DNA rearrangements. It triggers phage excision by cooperatively binding to sites X1 and X2 within the phage, bending DNA significantly and recruiting the phage-encoded integrase (Int) protein to site P2. We have determined the co-crystal structure of Xis with its X2 DNA-binding site at 1.7A resolution. Xis forms a unique winged-helix motif that interacts with the major and minor grooves of its binding site using an alpha-helix and an ordered beta-hairpin (wing), respectively. Recognition is achieved through an elaborate water-mediated hydrogen-bonding network at the major groove interface, while the preformed hairpin forms largely non-specific interactions with the minor groove. The structure of the complex provides insights into how Xis recruits Int cooperatively, and suggests a plausible mechanism by which it may distort longer DNA fragments significantly. It reveals a surface on the protein that is likely to mediate Xis-Xis interactions required for its cooperative binding to DNA.

PubMed: 15066428
DOI: 10.1016/j.jmb.2004.02.053

Experimental method

X-RAY DIFFRACTION (1.7 Å)