Restriction Enzymes

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Restriction Enzymes

• Nichole, Meghan
• Ashley, Dawne

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Contents

• Who Discovered the First Restriction Enzymes?
• How Were the First Restriction Enzymes
  Discovered?
• How Are Restriction Enzymes Named?

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Who Discovered the First Restriction Enzymes?

• In the late 1960's, scientists Stewart Linn and
  Werner Arber isolated examples of the two types
  of enzymes responsible for phage growth
  restriction in Escherichia coli E. coli bacteria.

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• This important development of a site specific
  nucleolus came when H.O. Smith, K.W. Wilcox, and
  T.J. Kelley, working at Johns Hopkins University
  in 1968 isolated and characterized the first
  restriction enzyme whose functioning depended on
  a specific DNA nucleotide sequence.

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How Were the First Restriction Enzymes Discovered?

• ? Restriction endonucleases were discovered
  during experiments to determine the ability of
  a bacteriophage, a virus that effects bacteria,
  to infect two different laboratory strains of
  Escherichia coli (E-coli).

Just Like Scissors Cut Paper
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How Restriction Enzymes Cut

• Some RE cut the foreign DNA randomly. While
  others recognize a particular DNA recognition
  sequence to cut at.
• Where a restriction endonuclease cuts within a
  DNA molecule is one of the primary
  characteristics by which it is classified

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• It is the recognition sites that provide the key
  to how one DNA fragment can be cut into two in a
  specific manner.

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Common Uses for Restriction Enzymes

• Cloning
• Southern Hybridization Analysis
• DNA Sequencing and Global Gene Expression
  Analysis (SAGE)
• Forensics

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How Are Restriction Enzymes Named?

• Restriction enzymes are named based on the
  bacteria in which they are isolated in the
  following manner
• EEscherichia (genus)
• Cocoli (species)
• RRY13(strain)

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Enzyme
Source

• HindIII Haemophilus influenzae
• 5'AAGCTT
• 3'TTCGAA
• 5'---A AGCTT---3'
• 3'---TTCGA A---5'

Recognition Sequence
Cut
Cut
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Enzyme
Source

• EcoRI Escherichia coli
• 5'GAATTC
• 3'CTTAAG
• 5'---G AATTC---3'
• 3'---CTTAA G---5'

Recognition Sequence
Cut
Cut
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Literature Cited

• Simmer, Megan and Dave Secko. Restriction
  Endonucleases Molecular Scissors for
  Specifically Cutting DNA. Molecular Biology. 4
  Nov. 2004.lthttp//www.bioteach.ubc.ca/MolecularBio
  logy/RestrictionEndonucleases/gt
• Restriction Enzyme. Wikipedia. 4 Nov 2004.
  http//en.wikipedia.org/wiki/Restriction_enzyme
• Robert J. Huskey. Restriction Enzymes Background
  Paper. 4 Nov 2004. http//en.wikipedia.org/wiki/
  Sites_of_cleavage.