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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]
Folded, 3-D structure of ribonuclease A. Anfinsen's dogma, also known as the thermodynamic hypothesis, is a postulate in molecular biology.It states that, at least for a small globular protein in its standard physiological environment, the native structure is determined only by the protein's amino acid sequence. [1]
Christian Boehmer Anfinsen Jr. (March 26, 1916 – May 14, 1995) [1] was an American biochemist.He shared the 1972 Nobel Prize in Chemistry with Stanford Moore and William Howard Stein for work on ribonuclease, especially concerning the connection between the amino acid sequence and the biologically active conformation (see Anfinsen's dogma).
Using the above principles, equations that relate a global protein signal, corresponding to the folding states in equilibrium, and the variable value of a denaturing agent, either temperature or a chemical molecule, have been derived for homomeric and heteromeric proteins, from monomers to trimers and potentially tetramers.
The term is also often used to describe the reformation (renaturation) of reverse-complementary strands that were separated by heat (thermally denatured). Proteins such as RAD52 can help DNA anneal. DNA strand annealing is a key step in pathways of homologous recombination.
In molecular biology, molecular chaperones are proteins that assist the conformational folding or unfolding of large proteins or macromolecular protein complexes. There are a number of classes of molecular chaperones, all of which function to assist large proteins in proper protein folding during or after synthesis, and after partial denaturation.
RNase A is a relatively small protein (124 residues, ~13.7 kDa). It can be characterized as a two-layer + protein with a deep cleft for binding the RNA substrate. The first layer is composed of three alpha helices (residues 3-13, 24-34 and 50-60
The hyperchromic effect is the striking increase in absorbance of DNA upon denaturation. The two strands of DNA are bound together mainly by the stacking interactions, hydrogen bonds and hydrophobic effect between the complementary bases. The hydrogen bond limits the resonance of the aromatic ring so the absorbance of the sample is limited as well.