BIO 103 Lecture Notes - Lecture 8: Dna Ligase, Restriction Fragment Length Polymorphism, Genetic Testing
9 Oct 2017
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Lecture 8 restriction enzymes and gel electrophoresis. Many enzymes have been isolated from variety of bacteria that have ability to cut dna strands into pieces. The enzymes bind to specific dna sequences and cut (or digest) across the dna ladder breaking the strong bonds of the backbone of dna molecule covalent, phosphodiester bond b/w the sugar and phosphate molecules. Restriction enzymes restrict the replication of bacteriophoage (bacteria virus) Restriction digest = phrase used to describe the breakdown of dna molecule by a restriction enzyme. Since initial discovery in the 1970s, over 100 restriction enzymes have been discovered. Named according to their bacterial source: ecor1 e. coli. Why doesn"t ecor1 cut up e. coli"s own dna. E. coli protects its own dna w/ chemical modification called methylation. This chemical signature prevents the enzyme ecor1 from cutting the dna. Bacteriophage dna is susceptible to be cupt because its dna is usually unmodified or unprotected.
