BIOB11H3 Lecture Notes - Lecture 6: Kozak Consensus Sequence, Eukaryotic Initiation Factor 3, Eif2
Document Summary
Ribosome attaches to mrna at start codon (aug) Polypeptide chain elongated steps repeated over until a stop codon is reached (uaa, uag or uga) Termination stop codon signals to stop elongation and release polypeptide. Eukaryotes 40s bound eifs eif1 conformational change to allow mrna binding eif1a conformational change to allow mrna binding eif3 interacts with eif4g on mrna complex eif2 gtp bound, enters p site after other eifs bind to. 40s subunit with met and is then ready to find 5" end on mrna, found by 43s subunit (scans until it finds kozak sequence (5"- Eukaryotes mrna eifs eif4e binds to 5" cap eif4a has helicase activity (moves around mrna molecule) Uses atp hydrolysis to unwind ds regions in mrna eif4g links 5"cap and 3" poly(a) tail converts mrna into circular message interacts with eif3 eif5b gtp bound to this and eif2 is hydrolyzed so. 60s subunit can attach to 40s subunit to form.
