Prokaryotic translation initiation and regulation

Understand how the start methionine is modified on the tRNA (fMet)

Know the name and function of the three tRNA binding sites in the ribosome complex

Be able to describe the four steps of the translation initiation sequence in prokaryotes (i.e. slide 8 of lecture 19 - be able to list them and write a few sentences about each)

Understand the importance of the Shine-Dalgarno sequence (you do not need to memorize the sequence but you should know where it is found, what it is used for and how it works)

Know the roles of the three initiation factors (IF-1, IF-2 and IF-3) where and the order in which they act

Understand how the initiation factors dissociate before the 70S ribosomal complex is formed

Understand the mechanisms of ribosomal control - I recommend you know at least one of the following in detail

• access to initiation sequences
• repression and activation by small regulatory RNAs
• riboswitches
• ribosomal processes
• antisense RNA

Other mechanisms to be familiar with:

• Formation of fMet-tRNAf^met

For mechanisms as well as the other proteins mentioned in the learning objectives, think about what would happen if you removed their functionality through mutagenesis.