Warren, David and Sam, My D and Manley, Kate and Sarkar, Dibyendu and Lee, Sang Yeol and Abbani, Mohamad and Wojciak, Jonathan M and Clubb, Robert T and Landy, Arthur (2003) Identification of the lambda integrase surface that interacts with Xis reveals a residue that is also critical for Int dimer formation. Proceedings of the National Academy of Sciences of the United States of America, 100 (14). pp. 8176-81. ISSN 0027-8424
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Abstract
Lambda integrase (Int) is a heterobivalent DNA-binding protein that together with the accessory DNA-bending proteins IHF, Fis, and Xis, forms the higher-order protein-DNA complexes that execute integrative and excisive recombination at specific loci on the chromosomes of phage lambda and its Escherichia coli host. The large carboxyl-terminal domain of Int is responsible for binding to core-type DNA sites and catalysis of DNA cleavage and ligation reactions. The small amino-terminal domain (residues 1-70), which specifies binding to arm-type DNA sites distant from the regions of strand exchange, consists of a three-stranded beta-sheet, proposed to recognize the cognate DNA site, and an alpha-helix. We report here that a site on this alpha-helix is critical for both homomeric interactions between Int protomers and heteromeric interactions with Xis. The mutant E47A, which was identified by alanine-scanning mutagenesis, abolishes interactions between Int and Xis bound at adjacent binding sites and reduces interactions between Int protomers bound at adjacent arm-type sites. Concomitantly, this residue is essential for excisive recombination and contributes to the efficiency of the integrative reaction. NMR titration data with a peptide corresponding to Xis residues 57-69 strongly suggest that the carboxyl-terminal tail of Xis and the alpha-helix of the aminoterminal domain of Int comprise the primary interaction surface for these two proteins. The use of a common site on lambda Int for both homotypic and heterotypic interactions fits well with the complex regulatory patterns associated with this site-specific recombination reaction.
| Item Type: | Article |
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| Additional Information: | Copyright of this article belongs to National Academy of Sciences. |
| Subjects: | Q Science > Q Science (General) |
| Depositing User: | Dr. K.P.S.Sengar |
| Date Deposited: | 14 Feb 2012 10:32 |
| Last Modified: | 14 Feb 2012 10:32 |
| URI: | http://crdd.osdd.net/open/id/eprint/929 |
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