2ALecture 14

Isolamon of bacterial mutants with high mutamon rates

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Unformatted text preview: g) is about 1/104 Is an incorrectly formed protein a mutaMon? Can incorrectly formed proteins cause a mutaMon? The mutQ gene MutaMons that cause defects in DNA repair, or the fidelity of DNA polymerase cause the mutant organism to be “hypermutable”. IsolaMon of bacterial mutants with high mutaMon rates, and sequencing of the genes affected, allows us to idenMfy the genes required for genome maintenance. The mutQ mutaMon turned out to be in a Mny gene ­ a tRNA! How could a mutant tRNA cause mutaMons? If a tRNA mutant has a “mutator” phenotype, then every error in transcripMon and translaMon might contribute, a li`le, to the overall spontaneous mutaMon rate. We have our aminoacyl tRNAs.  Now, on to the ribosome. What do ribosomes do? a.  b.  c.  d.  e.  They decide where to begin reading the triplet codons They a`ach an amino acid to a tRNA ­ making aminoacyl ­tRNA They fold the proteins They line up the aminoacyl ­tRNAs a and d a.  b.  c.  d.  e.  What else do ribosomes do? They establish the reading frame They proofread aminoacyl ­tRNAs They fall apart at stop codons They catalyze the formaMon of pepMde bonds a and d 3 2/9/10 •  Ribosomes Particles of >50 proteins and 3 rRNAs. Catalyze peptide bond formation. large subunit They are “ribozymes” What are ribozym...
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This note was uploaded on 02/16/2010 for the course BIS 34957 taught by Professor Britt during the Spring '10 term at UC Davis.

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