restriction enzyme
Noun: A restriction enzyme is a type of protein that acts as molecular scissors. It recognizes a specific, short sequence of nucleotides (a restriction site) within a DNA molecule and cuts the DNA at or near that site. These enzymes are naturally produced by bacteria as a defense mechanism to cut and disable the DNA of invading viruses. In biotechnology, they are essential tools for cutting DNA at precise locations, which is a fundamental step in recombinant DNA technology, genetic engineering, and DNA analysis.
Restriction enzymes are used to manipulate DNA sequences in a controlled manner. * Scientists use a restriction enzyme to cut a gene out of a chromosome. * The DNA fragment was produced by digesting the plasmid with a restriction enzyme. * Choosing the correct restriction enzyme is crucial for ensuring the DNA pieces have compatible ends for ligation.
- Restriction Enzyme Digestion: The process of using a restriction enzyme to cut DNA into fragments.
- The first step in cloning is often a restriction enzyme digestion of both the insert and the vector.
- Restriction Site: The specific DNA sequence recognized and cut by a given restriction enzyme.
- The gene of interest must not contain the restriction site for the enzyme we plan to use.
- Restriction Endonuclease: A more technical synonym for restriction enzyme, specifying it cuts within the DNA strand (endo-).
- Restriction Fragment: A piece of DNA resulting from cleavage by a restriction enzyme.
- Ligase: An enzyme that joins DNA fragments together, often used after restriction enzymes have created the fragments.
- Restriction endonuclease
- Molecular scissors (informal, descriptive term)
- Sticky Ends / Cohesive Ends: When a restriction enzyme cuts DNA strands unevenly, producing short, single-stranded overhangs that can easily bind to complementary sequences.
- Enzymes like EcoRI create sticky ends, which facilitate the joining of DNA fragments.
- Blunt Ends: When a restriction enzyme cuts both DNA strands at the same point, producing fragments with no overhang.
- SmaI is a restriction enzyme that generates blunt ends.
- DNA Ligase: The enzyme used to permanently join DNA fragments that have been cut by restriction enzymes.
- After the restriction enzyme cut the DNA, DNA ligase was used to seal the new gene into the plasmid.
- 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