Single-stranded DNA binding proteins (SSBs) play an important role in DNA processing events such as replication, recombination and repair. Human single-stranded DNA binding protein 1 (hSSB1/NABP2/OBFC2B) contains a single oligosaccharide/oligonucleotide binding (OB) domain followed by a charged C-terminus and is structurally homologous to the SSB from the hyperthermophilic crenarchaeote Sulfolo...

By coupling the protection and organization of single-stranded DNA (ssDNA) with recruitment and alignment of DNA processing factors, replication protein A (RPA) lies at the heart of dynamic multi-protein DNA processing machinery. Nevertheless, how RPA coordinates biochemical functions of its eight domains remains unknown. We examined the structural biochemistry of RPA's DNA-binding activity, co...

To investigate the in vivo effects of macromolecular crowding we examined the effect of inert macromolecules such as polyvinyl alcohol and polyethylene glycol on the in vitro activity of recA protein. The addition of either of these volume-occupying agents enables recA protein to promote homologous pairing and exchange of DNA strands at an otherwise nonpermissive magnesium ion concentration. In...

Single-stranded DNA-binding proteins (SSBs) play a key role in genome maintenance, binding and organizing single-stranded DNA (ssDNA) intermediates. Multimeric SSBs, such as the human mitochondrial SSB (HmtSSB), present multiple sites to interact with ssDNA, which has been shown in vitro to enable them to bind a variable number of single-stranded nucleotides depending on the salt and protein co...

AIMS To compare circulating matrix metalloproteinase (MMP) concentrations with antibodies to single and double stranded DNA (ssDNA and dsDNA) to determine their relation in inflammatory arthritic diseases, such as systemic lupus erythematosus (SLE). METHODS Fibroblast MMP-2 and neutrophil MMP-9 were resolved by gelatin zymography and measured by densitometry. Anti-ssDNA and anti-dsDNA were de...

Single-walled carbon nanotube (SWCNT)-based field-effect transistors (FETs) have been explored for use as biological/chemical sensors. Dopamine (DA) is a biomolecule with great clinical significance for disease diagnosis, however, SWCNT FETs lack responsivity and selectivity for its detection due to the presence of interfering compounds such as uric acid (UA). Surface modification of CNTs using...

It is known that the adsorption of short single-stranded DNA (ssDNA) on unmodified gold nanoparticles (AuNPs) is much faster than that for long ssDNA, and thus leads to length-dependent AuNPs aggregation after addition of salt, the color of the solutions sequentially changed from red to blue in accordance with the increase of ssDNA length. However, we found herein that the ssDNA sticky end of h...

The folding of biological macromolecules is a fundamental process which we lack full comprehension. Mostly studied in proteins and RNA, single-stranded DNA (ssDNA) also folds, at physiological salt conditions, by forming non-specific secondary structures that are difficult to characterize with biophysical techniques. Here present helix-coil model for structure formation, where ssDNA bases organ...

In Escherichia coli, the filament of RecA formed on single-stranded DNA (ssDNA) is essential for recombinational DNA repair. Although ssDNA-binding protein (SSB) plays a complicated role in RecA reactions in vivo, much of our understanding of the mechanism is based on RecA binding directly to ssDNA. Here we investigate the role of SSB in the regulation of RecA polymerization on ssDNA, based on ...

The hexameric Minichromosome Maintenance (MCM) protein complex forms a ring that unwinds DNA at the replication fork in eukaryotes and archaea. Our recent crystal structure of an archaeal MCM N-terminal domain bound to single-stranded DNA (ssDNA) revealed ssDNA associating across tight subunit interfaces but not at the loose interfaces, indicating that DNA-binding is governed not only by the DN...