Proof1 - : binding of repressor protein to specific...

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Proof-Reading During Translation Several amino acids are structurally similar. It is to be expected that amino acyl synthetases might make occasional mistakes. Example: valine and isoleucine constitute a pair of potentially ambiguous amino acids. In fact, isoleucyl synthetase makes this error at a frequency of 1/225 activation events. There is, however, a built-in editing mechanism. The incorrect amino acid is removed from the tRNA and the hydrolysis is catalyzed by the amino acyl synthetase. Regulation of translation : Important in both prokaryotes and eukaryotes (although regulation via transcription even more important) Example for one mechanism
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Unformatted text preview: : binding of repressor protein to specific sequence in particular mRNA ---------- translation inhibited specific example for regulation via repressor protein (Fig. 7.15): ferritin (protein that stores iron in cell) much iron: much ferritin needed little iron: little ferritin needed specific repressor protein for ferritin mRNA : much iron : repressor binds iron, ferritin mRNA is translated, much ferritin little iron : repressor cannot bind iron, instead binds to specific RNA sequence in ferritin mRNA called iron response element ( IRE ), ferritin mRNA is not translated, little ferritin...
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