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RecQ is a family of DNA helicase enzymes that are found in various organisms including bacteria, archaea, and eukaryotes (like humans). These enzymes play important roles in DNA metabolism during DNA replication, recombination, and repair. There are five known RecQ helicase proteins in humans: RecQ1, BLM, WRN, RecQ4, and RecQ5.
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 ]
In contrast, DNA Pol I is the enzyme responsible for replacing RNA primers with DNA. DNA Pol I has a 5′ to 3′ exonuclease activity in addition to its polymerase activity, and uses its exonuclease activity to degrade the RNA primers ahead of it as it extends the DNA strand behind it, in a process called nick translation. Pol I is much less ...
Before replication can take place, an enzyme called helicase unwinds the DNA molecule from its tightly woven form, in the process breaking the hydrogen bonds between the nucleotide bases. This opens up or "unzips" the double-stranded DNA to give two single strands of DNA that can be used as templates for replication in the above reaction.
New strands are created by enzymes called DNA polymerases. Both of these follow a similar pattern, called semi-conservative replication, in which individual strands of DNA are produced in different directions, which makes a leading and lagging strand. These lagging strands are synthesized by the production of Okazaki fragments that are soon joined.
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.
Restriction enzymes are endonucleases from eubacteria and archaea that recognize a specific DNA sequence. [3] The nucleotide sequence recognized for cleavage by a restriction enzyme is called the restriction site. Typically, a restriction site will be a palindromic sequence about four to six nucleotides long. Most restriction endonucleases ...
The first DNA topoisomerase was discovered in bacteria by James C. Wang in 1971 and was initially named ω (omega) protein; [3] it is now called Escherichia coli (E. coli) topoisomerase I (topo I) and is a representative of the type IA family of enzymes.