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GENE CLONING
Restriction Enzymes
- Also known as restriction endonucleases.
- Short nucleotide sequences isolated from prokaryotic organisms.
- Recognize specific sequences (~4 to 8 nucleotides).
- Bind to DNA at specific sites and cleave at the double helix.
- Cut the DNA fragment end with 3’-OH and 5’-P group.
- 2 types of restriction fragment:
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Sticky end: DNA fragment with short single stranded overhang.
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Blunt end: DNA fragment are fully base paired, no overhang.
- Methylated DNA:
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Self protection from cutting by own DNA by restriction enzymes.
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Transfer methyl group to adenine or cytosine residue to specific DNA sequences.
- 3 types of restriction enzymes:
- Nomenclature and types of restriction enzymes:
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