Open AccessCrystallization and structure determination of the core‐binding domain of bacteriophage lambda integrase
Author(s) -
Kamadurai Hari B.,
Jain Rinku,
Foster Mark P.
Publication year - 2008
Publication title -
acta crystallographica section f
Language(s) - English
Resource type - Journals
ISSN - 1744-3091
DOI - 10.1107/s174430910801381x
Subject(s) - integrase , dna , b3 domain , crystallography , stereochemistry , dna binding domain , binding domain , bacteriophage , chemistry , binding site , biochemistry , gene , escherichia coli , transcription factor
Bacteriophage lambda integrase catalyzes site‐specific DNA recombination. A helical bundle domain in the enzyme, called the core‐binding domain (Int CB ), promotes the catalysis of an intermediate DNA‐cleavage reaction that is critical for recombination and is not well folded in solution in the absence of DNA. To gain structural insights into the mechanism behind the accessory role of this domain in catalysis, an attempt was made to crystallize an Int CB –DNA complex, but crystals of free Int CB were fortuitously obtained. The three‐dimensional structure of DNA‐free Int CB was solved at 2.0 Å resolution by molecular replacement using as the search model the previously available DNA‐bound 2.8 Å structure of the Int CB domain in a larger construct of lambda integrase. The crystal structure of DNA‐free Int CB resembles the DNA‐bound structure of Int CB , but exhibits subtle differences in the DNA‐binding face and lacks electron density for ten residues in the C‐terminus that form a portion of a linker connecting Int CB to the C‐terminal catalytic domain of the enzyme. Thus, this work reveals the domain in the absence of DNA and allows comparison with the DNA‐bound form of this catalytically activating domain.