1p4e
Flpe W330F mutant-DNA Holliday Junction ComplexFlpe W330F mutant-DNA Holliday Junction Complex
Structural highlights
FunctionFLP_YEAST Part of the plasmid amplification system, which corrects any decrease in copy number caused by a rare missegregation event. Catalyzes the recombination between the large inverted repetitions of the 2-micron plasmid during plasmid replication. This recombination event changes the direction of one of the two replication forks in the bidirectionally replicating molecule, effectively resulting in multiple rounds of replication from a single initiation event. Binds specifically to the FLP recognition target (FRT) site where it induces DNA to bend. Three types of bend exist. Type I is approximately 60 degrees and results from 1 FLP molecule binding to 1 symmetry element. Type II is >144 degrees and results from FLP molecules binding to symmetry elements a and b. Type III is approximately 65 degrees and results from FLP molecules binding to symmetry elements b and c.[1] [2] [3] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe active site of Flp contains, in addition to a transdonated nucleophilic tyrosine, five other residues that are highly conserved within the lambda-integrase family of site-specific recombinases and the type IB topoisomerases. We have used site-directed mutagenesis and x-ray crystallography to investigate the roles of two such residues, Lys223 and Trp330. Our findings agree with studies on related enzymes showing the importance of Lys223 in catalysis but demonstrate that in Flp-mediated recombination the primary role of Trp330 is architectural rather than catalytic. Eliminating the hydrogen bonding potential of Trp330 by phenylalanine substitution results in surprisingly small changes in reaction rates, compared with dramatic decreases in the activities of W330A, W330H, and W330Q. The structure of a W330F mutant-DNA complex reveals an active site nearly identical to that of the wild type. The phenylalanine side chain preserves most of the van der Waals interactions Trp330 forms with the Tyr343-containing trans helix, which may be particularly important for the docking of this helix. Our studies of Trp330 provide the first detailed examination of this conserved residue in the lambda-integrase family, suggesting that the relative importance of active site residues may differ among Flp and related enzymes. The role of the conserved Trp330 in Flp-mediated recombination. Functional and structural analysis.,Chen Y, Rice PA J Biol Chem. 2003 Jul 4;278(27):24800-7. Epub 2003 Apr 27. PMID:12716882[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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