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The Hin recombinase of Salmonella normally catalyzes a site-specific DNA inversion reaction that is very efficient when the Fis protein and a recombinational enhancer sequence are present. The mechanism of this recombination reaction has been investigated by analyzing the formation and structure of knots generated in different plasmid substrates in vitro.(More)
BACKGROUND Hin is a member of an extended family of site-specific recombinases--the DNA invertase/resolvase family--that catalyze inversion or deletion of DNA. DNA inversion by Hin occurs between two recombination sites and requires the regulatory protein Fis, which associates with a cis-acting recombinational enhancer sequence. Hin recombinase dimers bind(More)
Fis, the most abundant DNA-binding protein in Escherichia coli during rapid growth, has been suspected to play an important role in defining nucleoid structure. Using bulk-phase and single-DNA molecule experiments, we analyze the structural consequences of non-specific binding by Fis to DNA. Fis binds DNA in a largely sequence-neutral fashion at nanomolar(More)
Transposons are a class of genetic elements that can move from one site in a cell's genome to another independently of the cell's general recombination system. Little is known about the mechanism of transposition of compound transposons such as Tn5, but it is thought that a transposon-encoded protein (a transposase) must recognize the outer ends of the(More)
The multistep kinetics through which DNA-binding proteins bind their targets are heavily studied, but relatively little attention has been paid to proteins leaving the double helix. Using single-DNA stretching and fluorescence detection, we find that sequence-neutral DNA-binding proteins Fis, HU and NHP6A readily exchange with themselves and with each(More)
In vitro studies have demonstrated that Hin-catalysed site-specific DNA inversion occurs within a tripartite invertasome complex assembled at a branch on a supercoiled DNA molecule. Multiple DNA exchanges within a recombination complex (processive recombination) have been found to occur with particular substrates or reaction conditions. To investigate the(More)
The Hin protein binds to two cis-acting recombination sites and catalyzes a site-specific DNA inversion reaction that regulates the expression of flagellin genes in Salmonella. In addition to the Hin protein and the two recombination sites that flank the invertible segment, a third cis-acting recombinational enhancer sequence and the Fis protein, which(More)
The Hin DNA invertase promotes a site-specific DNA recombination reaction in the Salmonella chromosome. The native Hin reaction exhibits overwhelming selectivity for promoting inversions between appropriately oriented recombination sites and requires the Fis regulatory protein, a recombinational enhancer, and a supercoiled DNA substrate. Here, we report a(More)
Determining numbers of proteins bound to large DNAs is important for understanding their chromosomal functions. Protein numbers may be affected by physical factors such as mechanical forces generated in DNA, e.g. by transcription or replication. We performed single-DNA stretching experiments with bacterial nucleoid proteins HU and Fis, verifying that the(More)
NHP6A is a non-sequence-specific DNA-binding protein from Saccharomyces cerevisiae which belongs to the HMGB protein family. Previously, we have solved the structure of NHP6A in the absence of DNA and modeled its interaction with DNA. Here, we present the refined solution structures of the NHP6A-DNA complex as well as the free 15bp DNA. Both the free and(More)