Si week 8 Brandon

Si week 8 Brandon - Si week 8 Brandon: -The required steps...

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Si week 8 Brandon: --The required steps for homologous recombination: 1) alignment of homologs 2) introduction of dna breaks (ss or ds) 3) strand invasion: 3‟ end of molecule invades other molecule and forms a holliday jxn 4) branch migration (in one direction) 5) resolution: holliday jxn is cleaved and dna molecules are separated --describe the following enzymes and their functions in dsDNA break repair a) RecBCD: processes DNA strand for invasion (in prokaryotes, damage to DNA creates dsDNA breaks i. Generates 3‟ overhang: w/Rec B/D (helicases with endonuclease activity) ii. Chi site causes one of the helicases to stop chewing the DNA, but the other keeps going to create the 3‟ overhand—RecC recognizes the Chi site b) RecA: loaded onto 3‟ end of ssDNA; binds to 3‟ ssDNA end and searches for homology on unbroken ds DNA (uses base flipping to test against ssDNA for complementarity) Needs at least a 15 bp match. Once these homologous regions anneal this forms the holliday jxn. c)
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This note was uploaded on 10/19/2010 for the course BISC 320 taught by Professor Aparicio during the Fall '08 term at USC.

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Si week 8 Brandon - Si week 8 Brandon: -The required steps...

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