Nascent peptide in the "birth canal" of the ribosome.

All proteins assembled by the ribosome must pass through the nascent-peptide exit tunnel. Some nascent peptides can specifically interact with the tunnel and affect the functions of the ribosome. The molecular mechanisms of such interactions and of the ribosome response are currently unknown. However, a recent study has revealed elements of the tunnel that might be involved in sensing the nascent-peptide sequence.