BIOL 3110 Lecture Notes - Lecture 17: Pyrimidine Dimer, Photolyase, Dna Mismatch Repair
Document Summary
Nov 28: how do cells eliminate dna damage, there are several ways to repair damaged dna, two mechanisms, dna repair of pyrimidine dimers: direct dna repair. Unlike mismatch repair where you cut out some nucleotides and resynthesize. Direct repair is a direct mechanism by which modified bases are taken back to unmodified state, no cutting of dna bonds, only bonds that are broken are ones that were made by a. For example, dna photolyase is an enzyme that exists in organisms that are exposed to uv light. After an organism makes pyrimidine dimer, the photolyase, can bind strongly to the pyrimidine dimer at 100x more affinity than to regular dna. The enzyme looks for them in the genome and binds, it is then activated by visible light. Its activation means that it will make electrons by using a cofactor which is fadh. It makes three electrons and they are used to reverse the cyclobutane ring to separate the pyrimidines.
