TLS Online TPP Program

#Id: 7094

#Unit 3. Fundamental Processes

TLS Online TPP Program

#Id: 7095

#Unit 3. Fundamental Processes

 A series of 3 G-C pairs in the stem that precedes the loop containing the anticodon is unique to tRNAf Met. These base pairs are required to allow the fMet- tRNAf to be inserted directly into the P site.

TLS Online TPP Program

#Id: 7096

#Unit 3. Fundamental Processes

Formylation is not strictly necessary because nonformylated Met-tRNAf can function as an initiator.

TLS Online TPP Program

#Id: 7097

#Unit 3. Fundamental Processes

In bacteria and mitochondria, the formyl residue on the initiator methionine is removed from the protein by a specific deformylase enzyme to generate a normal NH2 terminus.

TLS Online TPP Program

#Id: 7098

#Unit 3. Fundamental Processes

In about half the polypeptides, the methionine at the terminus is removed by an aminopeptidase, which creates a new terminus from R2 (originally the second amino acid incorporated into the chain). When both steps are necessary, they occur sequentially. The removal reaction(s) occur rather rapidly when the nascent polypeptide chain has reached a length of 15 amino acids.

TLS Online TPP Program

#Id: 7099

#Unit 3. Fundamental Processes