what is dna breathing
Answers
Answer:
DNA “breathing” (or “fraying”) refers to spontaneous local conformational fluctuations within double-stranded DNA (dsDNA). These conformational fluctuations lead to the breaking of base pairs at a temperature below the DNA melting temperature and exposure of these bases to the surrounding solvent. The opening of dsDNA results in a transient single-stranded DNA region (ssDNA; DNA bubble) containing one or more bases, possibly allowing proteins to gain their initial access to DNA. Several ensemble averaged methods have been used to study DNA breathing, including proton–tritium exchange (10) and proton–deuterium exchange by NMR (11), photoinduced DNA modification (12), and a combination of fluorescence quenching with fluorescence correlation spectroscopy (13). However, experimental observation of DNA breathing in real time is difficult in ensemble measurements due to the low frequency and short duration of base pair opening. Phelps et al. develop a unique approach of combining single-molecule FRET (smFRET) and single-molecule fluorescence linear dichroism (smFLD) to detect DNA breathing dynamics. The smFRET signal between a donor and an acceptor fluorophore on the same base pair of the opposite strands of DNA is detected using a total internal reflection fluorescence setup. In addition, rigid incorporation of the fluorophores and orientation constraints on the surface-tethered DNA allow the detection of the smFLD signal on polarized laser excitation, which reports on the changes in the orientation of the donor-labeled component in the laboratory frame independent of FRET. Kinetic information on a millisecond time scale is directly obtained from smFRET and smFLD time trajectories, whereas kinetic information with tens of microsecconds time resolution can be extracted from analysis with a time correlation function (TCF).
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〰️》Question :-
What is dna breathing.
✔Answer :-
DNA “breathing” (or “fraying”) refers to spontaneous local conformational fluctuations within double-stranded DNA (dsDNA). ... The opening of dsDNA results in a transient single-stranded DNA region (ssDNA; DNA bubble) containing one or more bases, possibly allowing proteins to gain their initial access to DNA.
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