CHEN 3701 Lecture Notes - Lecture 27: Okazaki Fragments, Interleukin 2, Dna Replication
26 Oct 2015
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Document Summary
Example: recombinant production of interleukin-2 in e. coli bacteria. Purify il-2 for circular dna, 2 replication forks both strands have okazaki fragments when you get to end of dna, can"t put rna strand ahead b/c there"s no ahead to put itso telomerase helps out with that. 1 error per 109 - 1010 nucleotides added. 4. 6 million base pairs in e. coli--> error per ~103-104 replications. Mechanisms: hydrogen bonding/base paring (a = t, c = g); more favorable to bond correctly geometry of at gc pairs within dna polymerase active site. -> but polymerization reaction yields 1 error per 104 - 105 nucleotides added (the previous 2 pieces give modest accuracywhat gives the rest of the accuracy to get error as low as above?) 3" to 5" exonuclease activity to proofread (102 - 103 fold improvement in accuracy) if incorrect, pulls out the incorrect one if this still results in some mistake.
