The Mechanism of Protein Synthesis

CHAPTER 40

The Mechanism of Protein Synthesis

Problems: 2,3,6,7,9,13,14,15,18,19,20

? Initiation: Locating the start codon.

? Elongation: Reading the codons (5'3') and synthesizing protein aminocarboxyl.

? Termination: Recognizing terminal codon and releasing protein.

Prokaryotes and Eukaryotes

40:1 Decoding the Information in mRNA

Exit Peptidyl Aminoacyl

Initiation

Start codon (also GUG, Val) Shine-Delgarno Sequence

Start: 1. Pairing of 16S

rRNA with SD of mRNA (a UTR). 2. Pairing of initiator tRNA with start codon.

Initiator tRNAf

Two different tRNA's that carry Met; tRNAf and tRNAm.

One Synthetase adds Met to both tRNAf and tRNAm.

A specific transformylase only formylates Met-tRNAf.

Initiation

Initiation factors, IF1, IF2 and IF3.

IF1 and IF3 prevent premature assembly of the 70S ribosome.

IF2 binds to fMet-tRNAf and mRNA at AUG codon.

The fMet-tRNAf in the fully assembled ribosome is in the P-site.

................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download