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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]
Some of these enzymes work by cutting the DNA helix and allowing one section to rotate, thereby reducing its level of supercoiling; the enzyme then seals the DNA break. [44] Other types of these enzymes are capable of cutting one DNA helix and then passing a second strand of DNA through this break, before rejoining the helix. [131]
Deoxyribonucleic acid (DNA) is a nucleic acid containing the genetic instructions used in the development and functioning of all known living organisms. The chemical DNA was discovered in 1869, but its role in genetic inheritance was not demonstrated until 1943. The DNA segments that carry this genetic information are called genes.
Histone-modifying enzymes are enzymes involved in the modification of histone substrates after protein translation and affect cellular processes including gene expression. [ 1 ] [ 2 ] To safely store the eukaryotic genome , DNA is wrapped around four core histone proteins (H3, H4, H2A, H2B), which then join to form nucleosomes .
DNA exists as a double-stranded structure, with both strands coiled together to form the characteristic double helix. Each single strand of DNA is a chain of four types of nucleotides. Nucleotides in DNA contain a deoxyribose sugar, a phosphate, and a nucleobase.
In molecular biology, endonucleases are enzymes that cleave the phosphodiester bond within a polynucleotide chain (namely DNA or RNA).Some, such as deoxyribonuclease I, cut DNA relatively nonspecifically (with regard to sequence), while many, typically called restriction endonucleases or restriction enzymes, cleave only at very specific nucleotide sequences.
These are known as palindromic (P) nucleotides due to the palindromic nature of the sequence produced when DNA repair enzymes resolve the overhang. [18] The process of hairpin opening by Artemis is a crucial step of V(D)J recombination and is defective in the severe combined immunodeficiency (scid) mouse model .
Deoxyribozymes, also called DNA enzymes, DNAzymes, or catalytic DNA, are DNA oligonucleotides that are capable of performing a specific chemical reaction, often but not always catalytic. This is similar to the action of other biological enzymes , such as proteins or ribozymes (enzymes composed of RNA ). [ 1 ]