We demonstrate here a novel single-molecule, label-free bioanalytical system capable of sensing the presence of specific ssDNA oligomer sequences and proteins with high selectivity and sensitivity. An ssDNA concentration of 1 nM and a Lyz concentration of 0.65 nM could be detected.

Bacteriophage N4 virion RNA polymerase transcription of double-stranded promoter-containing DNAs requires supercoiled template and E. coli single-stranded DNA-binding protein (EcoSSB); other single-stranded DNA-binding proteins cannot substitute. The DNA determinants of virion RNA polymerase binding at the promoter comprise a small template-strand hairpin. The requirement for EcoSSB is surprisi...

The DNA origami strategy for assembling designed supramolecular complexes requires ssDNA as a scaffold strand. A system is described that was designed approximately one third the length of the M13 bacteriophage genome for ease of ssDNA production. Folding of the 2404-base ssDNA scaffold into a variety of origami shapes with high assembly yields is demonstrated.

The emergence of DNA as the predominant hereditary material of life has necessitated the evolution of proteins whose sole function is the maintenance and care of these vital molecules. In a typical cell, there is a wide array of proteins with specialized functions in DNA metabolism that allow the cell to maintain and replicate its genome. In order to copy or make repairs to DNA, the double heli...

We have established an in vitro reaction in which heteroduplex DNA formation is dependent on the concerted actions of recA and recBCD proteins, the major components of the recBCD pathway of genetic recombination in vivo. We find that heteroduplex DNA formation requires three distinct enzymatic functions: first, the helicase activity of recBCD enzyme initiates heteroduplex DNA formation by unwin...

Human RAD52 promotes annealing of complementary single-stranded DNA (ssDNA). In-depth knowledge of RAD52-DNA interaction is required to understand how its activity is integrated in DNA repair processes. Here, we visualize individual fluorescent RAD52 complexes interacting with single DNA molecules. The interaction with ssDNA is rapid, static, and tight, where ssDNA appears to wrap around RAD52 ...

Structural studies of the Bacillus stearothermophilus PcrA protein along with biochemical studies of the single-stranded (ss) DNA translocation activity of PcrA monomers have led to the suggestion that a PcrA monomer possesses processive helicase activity in vitro. Yet definitive studies testing whether the PcrA monomer possesses processive helicase activity have not been performed. Here we sho...

Single-stranded DNA (ssDNA) with repetitive sequence was demonstrated to be a versatile nanotemplate for introducing biological activity in a self-assembled manner. Re-functionalization and rejuvenation of the ssDNA nanotemplate were achieved under mild biological conditions without using high temperature and strong alkaline treatment to denature DNA.

Using single stranded DNA (ssDNA) as a distance controller and Au nanoparticles (NPs) functionalized with ssDNA as novel energy-transfer nanoprobes, an ultrasensitive energy-transfer based photoelectrochemical protein biosensor was realized.