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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]
The most famous example is the hyperchromicity of DNA that occurs when the DNA duplex is denatured. [1] The UV absorption is increased when the two single DNA strands are being separated, either by heat or by addition of denaturant or by increasing the pH level. The opposite, a decrease of absorbance is called hypochromicity.
Under neutral conditions, hydrogen bonds reform between complementary base pairs, joining single strands to double-stranded DNA. Because the plasmid was so tightly coiled and small before the alkaline conditions were established, it can easily reanneal. The chromosomal DNA, however, because of its lengthy strands, does not anneal. [1]
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 ]
The polymerase chain reaction is the most widely used method for in vitro DNA amplification for purposes of molecular biology and biomedical research. [1] This process involves the separation of the double-stranded DNA in high heat into single strands (the denaturation step, typically achieved at 95–97 °C), annealing of the primers to the single stranded DNA (the annealing step) and copying ...
Denaturation: If alkaline transfer methods are used, the DNA gel is placed into an alkaline solution (typically containing sodium hydroxide) to denature the double-stranded DNA. The denaturation in an alkaline environment may improve binding of the negatively charged thymine residues of DNA to a positively charged amino groups of membrane ...
The other purine nucleoside, guanosine, is cleaved to form guanine. Guanine is then deaminated via guanine deaminase to form xanthine which is then converted to uric acid. Oxygen is the final electron acceptor in the degradation of both purines. Uric acid is then excreted from the body in different forms depending on the animal. [5]
A distinct group of DNA-binding proteins is the DNA-binding proteins that specifically bind single-stranded DNA. In humans, replication protein A is the best-understood member of this family and is used in processes where the double helix is separated, including DNA replication, recombination, and DNA repair. [ 123 ]