BIO230H1 Lecture Notes - Lecture 7: Hsp60, Protein Tag, Protein Kinase
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BIO230H1 Full Course Notes
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Document Summary
Translational control for protein regulation in response to stressful situations (low nutrients, infections, environmental stresses) Shine-dalgarno (sd) sequence: translation start site: 6 nucleotide sequence, upstream of aug start codon (~8 base pairs, correctly position ribosomes on mrna, can"t access sd sequence, won"t translate protein. Mechanisms: rna binding protein blocks sd sequence access, temperature-regulated rna structures, riboswitch, antisense rna. Shine-dalgarno sequence in the 5" untranslated region before the coding sequence: utr transcribed, but not translated. Translation repressor protein binds to 5" utr- blocks sd no translation. At low temperatures, the stem-loop rna blocks sd: stem dna complementary & anti-parallel = can bind to itself sd sequence not available. Higher temperatures- h-bonds b/w nucleotides breaks sd sequence exposed. Binding of ligand structural rearrangement of rna blocked sd sequence. Antisense rna produced elsewhere on genome base-pairs w/ mrna & blocks sd sequence. No shine-dalgarno sequence: translational repressors bind near initiator aug & inhibit translation.
