BIOL240 Study Guide - Final Guide: Histidine Kinase, Homoserine, Tryptophan

• School: University of Waterloo
• Department: Biology
• Course: BIOL240
• Professor: Josh Neufeld

Document Summary

Region upstream of the coding sequence (5" end); non-coding region. Fold into specific 3d structure that binds small molecules. Binding of a metabolite alters the structure of the riboswitch domain, preventing translation: structure blocks shine-dalgarno site and prevents ribosomes from binding to it. High concentration of thiamine pyrophosphate = metabolite binds, translation blocked. Low concentration of thiamine pyrophosphate = metabolite dissociates, translation. Controls translation, but may also control transcription. Premature termination of mrna synthesis (after initiation but before termination) Leader region (after promoter and operator) folds up into 2 alternative secondary structures: 1 structure allows continued rna synthesis, other structure causes premature termination. Best example: regulation of gene controlling the biosynthesis of certain amino acids in gram- negative bacteria. Attenuation is absent from eukarya b/c transcription and translation and spatially separated! Leader sequence encodes a short polypeptide (leader peptide) that functions as an attenuator. If trp is plentiful, tryptophan trnas and the leader peptide will be synthesized.