Sequence-dependent secondary DNA structures, such as cruciform or triplex DNA, are implicated in regulation of gene transcription and other important biological processes at the molecular level. Sequences capable of forming these structures can readily be identified in entire genomes by appropriate searching techniques. However, not every DNA segment containing the proper sequence has equal pro...

background while tuberculosis (tb) can be diagnosed by microscopy and culture, the sensitivity of ziehl-neelsen staining is variable and culture results require 4 - 8 weeks to be determined. polymerase chain reaction (pcr) and its modifications, including nested pcr, might be promising methods for the rapid diagnosis of tb. objectives this study aimed to evaluate the performance of nested pcr o...

The Holliday junction, the key intermediate of recombination, is generated by strand exchange resulting in a covalent connection between two recombining DNA molecules. Translocation of a Holliday junction along DNA, or branch migration, progressively exchanges one DNA strand for another and determines the amount of information that is transferred between two recombining partners. In Escherichia...

Branch migration of a DNA Holliday junction is a key step in genetic recombination. Previously, it was shown that a single base-pair heterology between two otherwise identical DNA sequences is a substantial barrier to passage of a Holliday junction during spontaneous branch migration. Here, we exploit this inhibitory effect of sequence heterology to estimate the step size of branch migration. W...

The heterodimeric nuclease Mus81-Eme1 has been proposed to be a Holliday junction resolvase and has now been found to be responsible for nearly all meiotic crossovers in fission yeast. The intriguing substrate preference of this enzyme for nicked Holliday junctions opens the possibility that crossover formation may not always involve double Holliday junctions.

The SLX4 protein functions as a platform for catalytic subunits of structure-specific endonucleases. Findings reported in Cell (Fekairi et al., 2009; Svendsen et al., 2009) and in Molecular Cell (Andersen et al., 2009; Muñoz et al., 2009) now identify the human SLX4 and show that in association with the SLX1 endonuclease it directs the symmetric cleavage and resolution of Holliday junctions.

Three single-molecule techniques have been used simultaneously and in tandem to track the formation in vitro of single XerCD-dif recombination complexes. We observed the arrival of the FtsK translocase at individual preformed synaptic complexes and demonstrated the conformational change that occurs during their activation. We then followed the reaction intermediate transitions as Holliday junct...

The heterodimeric HU protein, highly conserved in bacteria and involved in transposition, recombination, DNA repair, etc., shares similarity with histones and HMGs. HU, which binds DNA with low affinity and without sequence specificity, binds strongly and specifically to DNA junctions and DNA containing single-strand breaks. The fine structure of these specific complexes was studied by footprin...