Restriction enzymes: Difference between revisions

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 Restriction Enzymes, or Restriction Endonucleases cut DNA into smaller fragments (Alberts et al., 2008).
Restriction enzymes, or restriction endonucleases, are enzymes which&nbsp;cut DNA into&nbsp;defined fragments <ref>Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K., Walter, P., 2008. Molecular Biology of the Cell. 5th Ed. New York: Garland Science</ref>.  


There are two kinds of restriction enzymes, there is Endonuclease and Exonuclease. Exonuclease digests ends of DNA whereas Endonuclease digests in-between the ends.  
Different restriction enzymes recognise different squences, normally between 4 to 8 nucleotides in length. Some restriction enzymes produce staggered or [[Sticky ends|'sticky' ends]] while others leave [[Blunt ends|blunt ends]]<ref>Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K., Walter, P., 2008. Molecular Biology of the Cell. 5th Ed. New York: Garland Science</ref>. Sticky ends are produced when some unpaired nucleotides at the end of the dsDNA are present, creating overhangs which can be either 3' or 5' overhangs. Blunt ends are created when both strands are cut in the same position, straight down the middle, with no overhangs.&nbsp;Examples of restriction enzymes that produce staggered ends are [[EcoR1|EcoR1]] and [[Hind111|Hind111]]<ref>Dryden, D.T.F., Loenen, W.A.M., Murray, N.E., Raleigh, E.A., Wilson, G.G., 2013. Highlights of the DNA Cutters: a short history of restriction enzymes. Nucleic Acids Research, 42(1), pp 3-19.</ref>. Hpal and AluI are examples of restriction enzymes that form blunt ends <ref>Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K., Walter, P., 2008. Molecular Biology of the Cell. 5th Ed. New York: Garland Science</ref>.&nbsp;An example of use of restriction enzymes in&nbsp;practice&nbsp;is in&nbsp;[[Agarose gel electrophoresis|electrophoresis]]&nbsp;and [[Polymerase Chain Reaction (PCR)|PCR]].  


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Restriction enzymes are often used to create recombinant DNA molecules. See&nbsp;[[Recombinant DNA Technology]].<br>


Different restriction enzymes recognise different squences, normally between 4 to 8 nucleotides in length. Some restriction enzymes produce staggered or 'sticky' ends while others leave blunt ends&nbsp;(Alberts et al., 2008). Examples of restriction enzymes that produce staggered ends are EcoR1 and Hind111 (Dryden et al., 2013). Hpal is an example of a restriction enzyme that forms blunt ends (Alberts et al., 2008).&nbsp;
=== References<br> ===


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Restriction Enzymes are often used to create recombinant DNA molecules. See&nbsp;[[Recombinant_DNA_Technology]].
 
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'''References'''
 
Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K., Walter, P., 2008. Molecular Biology of the Cell. 5th Ed. New York: Garland Science
 
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Dryden, D.T.F., Loenen, W.A.M., Murray, N.E., Raleigh, E.A., Wilson, G.G., 2013. Highlights of the DNA Cutters: a short history of restriction enzymes. ''Nucleic Acids Research'', 42(1), pp 3-19.
 
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Latest revision as of 10:21, 19 October 2016

Restriction enzymes, or restriction endonucleases, are enzymes which cut DNA into defined fragments [1].

Different restriction enzymes recognise different squences, normally between 4 to 8 nucleotides in length. Some restriction enzymes produce staggered or 'sticky' ends while others leave blunt ends[2]. Sticky ends are produced when some unpaired nucleotides at the end of the dsDNA are present, creating overhangs which can be either 3' or 5' overhangs. Blunt ends are created when both strands are cut in the same position, straight down the middle, with no overhangs. Examples of restriction enzymes that produce staggered ends are EcoR1 and Hind111[3]. Hpal and AluI are examples of restriction enzymes that form blunt ends [4]. An example of use of restriction enzymes in practice is in electrophoresis and PCR.

Restriction enzymes are often used to create recombinant DNA molecules. See Recombinant DNA Technology.

References

  1. Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K., Walter, P., 2008. Molecular Biology of the Cell. 5th Ed. New York: Garland Science
  2. Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K., Walter, P., 2008. Molecular Biology of the Cell. 5th Ed. New York: Garland Science
  3. Dryden, D.T.F., Loenen, W.A.M., Murray, N.E., Raleigh, E.A., Wilson, G.G., 2013. Highlights of the DNA Cutters: a short history of restriction enzymes. Nucleic Acids Research, 42(1), pp 3-19.
  4. Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K., Walter, P., 2008. Molecular Biology of the Cell. 5th Ed. New York: Garland Science