1LX8
Regulation of directionality in bacteriophage lambda site-specific recombination: structure of the Xis protein
Summary for 1LX8
| Entry DOI | 10.2210/pdb1lx8/pdb |
| Descriptor | Excisionase (1 entity in total) |
| Functional Keywords | dna architectural protein, 'winged'-helix protein, phage excision, site-specific dna recombination, viral protein |
| Biological source | Enterobacteria phage lambda |
| Total number of polymer chains | 1 |
| Total formula weight | 6793.80 |
| Authors | Sam, M.D.,Papagiannis, C.,Connolly, K.M.,Corselli, L.,Iwahara, J.,Lee, J.,Phillips, M.,Wojciak, J.M.,Johnson, R.C.,Clubb, R.T. (deposition date: 2002-06-04, release date: 2003-06-10, Last modification date: 2024-05-22) |
| Primary citation | Sam, M.D.,Papagiannis, C.,Connolly, K.M.,Corselli, L.,Iwahara, J.,Lee, J.,Phillips, M.,Wojciak, J.M.,Johnson, R.C.,Clubb, R.T. Regulation of directionality in bacteriophage lambda site-specific recombination: structure of the Xis protein J.Mol.Biol., 324:791-805, 2002 Cited by PubMed Abstract: Upon induction of a bacteriophage lambda lysogen, a site-specific recombination reaction excises the phage genome from the chromosome of its bacterial host. A critical regulator of this process is the phage-encoded excisionase (Xis) protein, which functions both as a DNA architectural factor and by cooperatively recruiting integrase to an adjacent binding site specifically required for excision. Here we present the three-dimensional structure of Xis and the results of a structure-based mutagenesis study to define the molecular basis of its function. Xis adopts an unusual "winged"-helix motif that is modeled to interact with the major- and minor-grooves of its binding site through a single alpha-helix and loop structure ("wing"), respectively. The C-terminal tail of Xis, which is required for cooperative binding with integrase, is unstructured in the absence of DNA. We propose that asymmetric bending of DNA by Xis positions its unstructured C-terminal tail for direct contacts with the N-terminal DNA-binding domain of integrase and that an ensuing disordered to ordered transition of the tail may act to stabilize the formation of the tripartite integrase-Xis-DNA complex required for phage excision. PubMed: 12460578DOI: 10.1016/S0022-2836(02)01150-6 PDB entries with the same primary citation |
| Experimental method | SOLUTION NMR |
Structure validation
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