Definition of Restriction nuclease
1. Noun. Any of the enzymes that cut nucleic acid at specific restriction sites and produce restriction fragments; obtained from bacteria (where they cripple viral invaders); used in recombinant DNA technology.
Medical Definition of Restriction nuclease
Class of bacterial enzymes that cut DNA at specific sites. In bacteria their function is to destroy foreign DNA, such as that of bacteriophages (host DNA is specifically modified at these sites).
Type I restriction endonucleases occur as a complex with the methylase and a polypeptide that binds to the recognition site on DNA. They are often not very specific and cut at a remote site.
Type II restriction endonucleases are the classic experimental tools. They have very specific recognition and cutting sites. The recognition sites are short, 4-8 nucleotides and are usually palindromic sequences. Because both strands have the same sequence running in opposite directions the enzymes make double stranded breaks, which, if the site of cleavage is off centre, generates fragments with short single stranded tails, these can hybridise to the tails of other fragments and are called sticky ends.
They are generally named according to the bacterium from which they were isolated (first letter of genus name and the first two letters of the specific name). The bacterial strain is identified next and multiple enzymes are given Roman numerals. For example the two enzymes isolated from the R strain of E. Coli are designated Eco RI and Eco RII.
(10 Mar 1998)
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Lexicographical Neighbors of Restriction Nuclease
Literary usage of Restriction nuclease
Below you will find example usage of this term as found in modern and/or classical literature:
1. Biotechnology in International Agricultural Research: Proceedings of the by International Rice Research Institute (1985)
"... the Tn5-carrying DNA with the restriction nuclease EcoR1 yields the complete
Tn5 probe plus flanking portions of the target DNA. ..."
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