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In biochemistry, denaturation is a process in which proteins or nucleic acids lose folded structure present in their native state due to various factors, including application of some external stress or compound, such as a strong acid or base, a concentrated inorganic salt, an organic solvent (e.g., alcohol or chloroform), agitation and radiation, or heat. [3]
Furthermore, one can assess whether the folding proceeds according to a two-state unfolding as described above. This can be done with differential scanning calorimetry by comparing the calorimetric enthalpy of denaturation i.e. the area under the peak, A peak {\displaystyle A_{\text{peak}}} to the van 't Hoff enthalpy described as follows:
The process of DNA denaturation can be used to analyze some aspects of DNA. Because cytosine / guanine base-pairing is generally stronger than adenine / thymine base-pairing, the amount of cytosine and guanine in a genome is called its GC-content and can be estimated by measuring the temperature at which the genomic DNA melts. [2]
Heat denaturation of DNA, also called melting, causes the double helix structure to unwind to form single stranded DNA. When DNA in solution is heated above its melting temperature (usually more than 80 °C), the double-stranded DNA unwinds to form single-stranded DNA. The bases become unstacked and can thus absorb more light.
The schematic diagram indicates the roles of insufficient DNA repair in aging and cancer, and the role of apoptosis in cancer prevention. An excess of naturally occurring DNA damage, due to inherited deficiencies in particular DNA repair enzymes, can cause premature aging or increased risk for cancer (see DNA repair-deficiency disorder).
The HD gene [8] is found in all human genomes. In the event that a slippage event occurs there can be a large expansion in the tandem repeats of the HD gene. [8] An individual who is not affected by Huntington's disease will have 6-35 tandem repeats at the HD locus. However, an affected individual will have 36- 121 repeats present. [7]
Structure of the base-excision repair enzyme uracil-DNA glycosylase excising a hydrolytically-produced uracil residue from DNA. The uracil residue is shown in yellow. When only one of the two strands of a double helix has a defect, the other strand can be used as a template to guide the correction of the damaged strand.
DNA gyrase, or simply gyrase, is an enzyme within the class of topoisomerase and is a subclass of Type II topoisomerases [1] that reduces topological strain in an ATP dependent manner while double-stranded DNA is being unwound by elongating RNA-polymerase [2] or by helicase in front of the progressing replication fork.