BIO206H5 Lecture 12: BIO206 Lecture 12 Chapter 7.pdf
Document Summary
Cell-free protein synthesizing system poly-u (uuuuuuu ) only polyphe (phe-phe-phe ) poly-a (aaaaaaa ) only polylys (lys-lys-lys ) poly-c (cccccccc) only polypro (pro-pro-pro ) Then used copolymers (>1 nucleotide) containing 2,3,4 codons to infer other codes for amino acids. Technology to sequence rna and proteins had not been developed so they couldn"t just compare sequences of the two. Their system - gently lysed bacterial cells, centrifuged to remove cell membranes etc. Left with all the things needed to make protein cell free. Treated with dnase to remove endogenous dna - system is ready. Added synthetic dna polymers and analysed composition of the polypeptides they got. Cant do ggggg - it assembles into a mess. Then used more complicated synthetic dna to work out the rest of the code. Codon: group of bases that specifies a single amino acid. The code is read in units of 3 nucleotides. 3 bases per codon (triplet) = 64 combinations.
