Search results
Results from the WOW.Com Content Network
The restriction modification system (RM system) is found in bacteria and archaea, and provides a defense against foreign DNA, such as that borne by bacteriophages.. Bacteria have restriction enzymes, also called restriction endonucleases, which cleave double-stranded DNA at specific points into fragments, which are then degraded further by other endonucleases.
This article contains a list of restriction enzymes whose names start with A and have a clearly defined cutting site. The following information is given for each enzyme: Name of Restriction Enzyme: Accepted name of the molecule, according to the internationally adopted nomenclature, [1] [2] and bibliographical references. Note: When ...
A restriction enzyme or restriction endonuclease is a special type of biological macromolecule that functions as part of the "immune system" in bacteria.One special kind of restriction enzymes is the class of "homing endonucleases", these being present in all three domains of life, although their function seems to be very different from one domain to another.
Different restriction enzymes acting on different recognition sites produce different DNA fragments. The term restriction enzyme originated from the studies of phage λ, a virus that infects bacteria, and the phenomenon of host-controlled restriction and modification of such bacterial phage or bacteriophage. [12]
E. coli BL21(DE3) lacks a functional type I restriction-modification system, indicated by hsdS(r B − m B −). Specifically, both the restriction (hsdR) and modification (hsdM) domains are inactive. This enhances transformation efficiency since exogenously introduced unmethylated DNA remains untargeted by the restriction-modification system. [9]
This article contains a list of the most studied restriction enzymes whose names start with O to R inclusive. It contains approximately 130 enzymes. The following information is given: Enzyme: Accepted name of the molecule, according to the internationally adopted nomenclature [1] [2], and bibliographical references.
Several databases exist for restriction sites and enzymes, of which the largest noncommercial database is REBASE. [5] [6] Recently, it has been shown that statistically significant nullomers (i.e. short absent motifs which are highly expected to exist) in virus genomes are restriction sites indicating that viruses have probably got rid of these motifs to facilitate invasion of bacterial hosts. [7]
Type III site-specific deoxyribonuclease (EC 3.1.21.5, type III restriction enzyme, restriction-modification system) is an enzyme. [1] This enzyme catalyses the following chemical reaction Endonucleolytic cleavage of DNA to give specific double-stranded fragments with terminal 5'- phosphates