A RecA-single-stranded DNA (RecA-ssDNA) filament searches a genome for sequence homology by rapidly binding and unbinding double-stranded DNA (dsDNA) until homology is found. We demonstrate that pulling on the opposite termini (3' and 5') of one of the two DNA strands in a dsDNA molecule stabilizes the normally unstable binding of that dsDNA to non-homologous RecA-ssDNA filaments, whereas pulli...

We have analyzed in greater detail the interaction of strand exchange protein 1 (Sep1) from Saccharomyces cerevisiae with DNA. The binding site size of Sep1 on single-stranded DNA (ssDNA) was determined to be 70 nucleotides per protein monomer using a fluorescence assay and 100 nucleotides using an exonuclease titration technique. The amount of Sep1 required for maximum aggregation of ssDNA was...

Abstract Fluorophore 1,8-naphthilamide was linked to 2-bromoacridine through an ethylenediamine spacer using a succinct synthetic route give bromoacridine-linked, bifunctional fluorophore conjugate for the detection of triplex DNA. Acridine is well known intercalate into duplex DNA whereas introduction bulky bromine atom at position C2 redirects specificity over In this work, photoelectron tran...

Nick Wierckx,1 M. Auxiliadora Prieto,2 Pablo Pomposiello,3 Victor de Lorenzo,4 Kevin O’Connor5,6 and Lars M. Blank1* Institute of Applied Microbiology – iAMB, Aachen Biology and Biotechnology – ABBt, RWTH Aachen University, Worringerweg 1, Aachen 52074, Germany. Biological Research Center, The Spanish National Research Council (CIB-CSIC), C/ Ramiro de Maeztu, 9, Madrid 28040, Spain. Bacmine, Ca...

Yeast RAD51 gene functions in genetic recombination and DNA double-strand break repair. In vitro, in the presence of ATP and replication protein A, RAD51 protein pairs single-stranded DNA (ssDNA) with homologous double-stranded DNA (dsDNA) and catalyzes strand exchange between the synapsed DNA partners. Electron microscopic analyses show that RAD51 forms helical filaments on both ssDNA and dsDN...

The RecA proteins of Escherichia coli (Ec) and Deinococcus radiodurans (Dr) both promote a DNA strand exchange reaction involving two duplex DNAs. The four-strand exchange reaction promoted by the DrRecA protein is similar to that promoted by EcRecA, except that key parts of the reaction are inhibited by Ec single-stranded DNA-binding protein (SSB). In the absence of SSB, the initiation of stra...

We report a novel electrochemical sensing system for single-stranded DNA (ssDNA) with a specific sequence based on the catalytic reduction of protons with platinum deposited by the electrochemical reduction of chloro-2,2':6',2''-terpyridine platinum(II) chloride dihydrate (Pt complex) on a glassy carbon (GC) electrode. There was no catalytic property observed for proton reduction at the GC elec...

To carry out homologous recombination events in the cell, recombination proteins must be able to recognize and form presynaptic filaments on single-stranded DNA (ssDNA) in the presence of a vast excess of double-stranded DNA (dsDNA). Therefore recombination machineries stringently discriminate between ssDNA and dsDNA lattices. Recent single-molecule studies of bacteriophage T4 recombination pro...

In this paper, we report on the large-scale formation of supramolecular rhombus microparticles (SRMs) driven by electrostatic assembly, carried out by direct mixing of an aqueous HAuCl(4) solution and an ethanol solution of 4,4'-bipyridine at room temperature. We further demonstrate their use as an effective fluorescent sensing platform for nucleic acid detection with a high selectivity down to...

Homologous recombination (HR) is a crucial pathway for double-stranded DNA break (DSB) repair. During the early stages of HR, the newly generated DSB ends are processed to yield long single-stranded DNA (ssDNA) overhangs, which are quickly bound by replication protein A (RPA). RPA is then replaced by the DNA recombinase Rad51, which forms extended helical filaments on the ssDNA. The resulting n...