BCMB20005 Lecture 11: Lecture 11

• School: University of Melbourne
• Department: Biochemistry and Molecular Biology
• Course: BCMB20005
• Professor: Amber Willems

Document Summary

Expression systems: referred to by the host / dna source or delivery mechanism. Choice of best expression system depends on the gene involved, e. g. saccharomyces cerevisiae is preferred for proteins that require significant posttranslational modification. Structure determination experiments, e. g. x-ray crystallography or nmr : bacterial or yeast expression are advantageous as they produce large amounts of protein. Enzyme kinetics affect of cofactors on activity. Protein is of prokaryotic origin, use e. coli expression system (quick/cheap/have correct machinery) Many eukaryotic proteins don"t fold properly in e. coli and may form inclusion bodies , so use an eukaryotic expression system : better equipped to fold proteins from an eukaryotic source. Many proteins need modifications after translation to become active and/or adopt the correct structure, e. g. removal of n-terminal methionine residue. Phosphorylation (exclusively carried out by eukaryotic cells) Can find out by using the codon usage database) (www. kazusa. or. jp/codon/) Review low usage codons" according to organism (recall lecture 10)