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Showing 1 to 18 of 18 for “"DNA unwinding"”.
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Single-molecule optical tweezers studies of the mechanism of DNA unwinding by a model helicase
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2023-09-01 without embargo terms
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Functional characterization of Pura in vivo and in vitro - Pura knock-out mice and Pura DNA unwinding activity
Pura is a ubiquitous DNA- and RNA-binding protein that is highly conserved in eukaryotic organisms. Pura binds preferentially to purine-rich single-stranded DNA. To date, biochemical analyses of Pura have indicated that this protein might be involved in diverse cellular functions, including DNA …
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Mechanism of Mcm10 function during DNA replication
… do so with limited errors. In eukaryotic cells, DNA replication is accomplished by a multi-stage process involving numerous protein assemblies. The core component of this process is the replicative DNA helicase, Mcm2-7. Mcm2-7 complexes are loaded around origins of DNA replication during G1 …
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Mechanism and importance of Mcm2-7 double-hexamer formation during DNA replication initiation
… and accurately in each cell cycle. Thus, DNA replication is a highly-regulated multi-step process that ensures the genome is duplicated only once per cell cycle. In eukaryotic cells, initiation of DNA replication begins with loading of two heterohexameric Mcm2-7 helicases around origin DNA …
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Critical role of histone tail entropy in nucleosome unwinding
… long-lasting genome stability while keeping the DNA accessible to protein molecules. Using a transferable protein-DNA model and advanced sampling techniques, we investigated the stability and dynamics of the nucleosome by determining the free energy cost of its DNA unwinding. Simulation results …
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Direct observation of XPD helicase base-pair stepping and regulation by RPA2
Although it is known that single-stranded DNA binding proteins (SSB) can stimulate helicase activity, the mechanism by which this occurs may be more complex than sequestering ssDNA products of duplex separation. Here, we present a singlemolecule helicase assay with base-pair sensitivity, which …
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Single-molecule studies of the mechanism of eukaryotic helicase activation
Eukaryotic DNA replication is a fundamental process that must occur accurately and only once per cell cycle. To ensure that origins only initiate once per cell cycle, the events of DNA replication initiation are temporally separated to different phases of the cell cycle. This regulation separates …
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Single-molecule optical trapping studies of the regulation mechanisms of XPD helicase
DNA is more than just a molecule. It is the blueprint of life, encoding the instructions that connect generations, shape identities, and reveal the mysteries of biology. Maintaining DNA integrity is essential, as repair, replication, and protective networks ensure that the genetic code is …
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Development of methods to investigate poly(ADP-ribose) polymerase-1 activity and DNA base-excision repair in relation to cancer and ageing
… automation of the fluorescence detected alkaline DNA unwinding (FADU) assay to measure DNA strand breaks and repair. Poly(ADP-ribose) polymerase-1 (PARP-1) is involved in DNA base-excision repair and the maintenance of genomic stability, but emerges to have many more functions in cellular …
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Exploration of helicase mechanisms at single molecule level: answering decades old questions and bioengineering super proteins
… force spectroscopy to study translocation and unwinding mechanism of Escherichia coli Rep, a model helicase with 3’5’ motor translocation activity on single‐stranded DNA (ssDNA) fueled by ATP hydrolysis. When a translocating Rep on a 3’‐overhang DNA reaches the DNA duplex junction, instead of …
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Exploration of helicase mechanisms at single molecule level: answering decades old questions and bioengineering super proteins
… force spectroscopy to study translocation and unwinding mechanism of Escherichia coli Rep, a model helicase with 3’5’ motor translocation activity on single‐stranded DNA (ssDNA) fueled by ATP hydrolysis. When a translocating Rep on a 3’‐overhang DNA reaches the DNA duplex junction, instead of …
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Uncovering vital molecular contacts within the replisome and characterizing fail-safe mechanisms ensuring genomic stability in E. coli.
… linker in the τ-subunit tethers α-Pol III to the DnaB helicase for efficient DNA replication in E. coli. Therefore, disrupting interactions between τ-CLC and α-Pol III also disrupts coordination with the DnaB helicase. To probe this phenomenon, we initiated our study through in vitro …
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The Roles of the Mcm2-7 Tails in Replication Initiation
DNA replication is complex biological reaction that spans two stages of the eukaryotic cell cycle. In G1 phase, preparation for replication begins when two copies of the replicative helicase, the Mcm2-7 complex, are loaded onto DNA. However, these helicases are loaded in an inactive state, and are …
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Single molecule force spectroscopy of single stranded DNA binding protein and Rep helicase
Single-stranded DNA binding (SSB) proteins are essential accessory proteins that protect single-stranded DNA (ssDNA) during genome maintenance. Escherichia coli SSB is a prototypical homo-tetrameric SSB protein that can wrap up to 65 nucleotides of ssDNA in one of its binding modes. Here we present …
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Single molecule fluorescence studies of replicative helicases
DNA helicases are motor enzymes that convert the chemical energy of nucleotide triphosphate hydrolysis into mechanical energy for translocation on single stranded (ss) DNA and unwinding of double stranded (ds) DNA. All of the 12 known replicative helicases are hexameric helicases that are …
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Single molecule investigations into DNA replication, recombination and repair
Double-stranded DNA breaks (DSBs) is a principal cytotoxic damage that can be repaired by several well-known repair pathways. One of the most prominent routes is the homologous recombination (HR). The mechanism of repair has been studied primarily by biochemical analysis over the years. Recent …
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A study of acetylcholinesterase and cholinesterase in the fetal mouse brain and a study of the effects of three teratogens, vitamin A, cyclophosphamide and sodium valproate on the fetal mouse central nervous system
… of cyclophosphamide and vitamin A on cephalic DNA damage utilising a DNA unwinding assay to detect DNA strand breaks. Substantial acetylcholinesterase activity of ± 3nmol/min/mg was present in 17-day to 19-day fetal mouse brains and 5 isoenzymes were present on electrophoresis. The contribution …
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DNA double-strand break repair studied by atomic force microscopy
DNA double-strand breaks (DSBs), where both strands of the DNA duplex are simultaneously fractured, are considered the most lethal type of DNA damage. The conserved Mre11-Rad50 DNA repair complex enables the catalytic activities of the Mre11 nuclease and the Rad50 ATPase to function together to …