Structural Insight into Nascent Polypeptide Chain-Mediated Translational Stalling

Nascent peptide-mediated ribosome stalling promoted by antibiotics

Nascent polypeptide-associated complex stimulates protein import into yeast mitochondria.

To identify yeast cytosolic proteins that mediate targeting of precursor proteins to mitochondria, we developed an in vitro import system consisting of purified yeast mitochondria and a radiolabeled mitochondrial precursor protein whose C terminus was still attached to the ribosome. In this system, the N terminus of the nascent chain was translocated across both mitochondrial membranes, generat...

Dissection of a co-translational nascent chain separation event.

Some RNA and protein sequences are capable of directing changes to the course of translation from that expected from the mRNA sequence, and this process is termed translational 'recoding'. 'CHYSEL' peptides are approximately 19-amino-acid sequences found in many viral genomes. When translated at internal portions of polypeptides, they yield co-translational separation of the nascent chain at th...

Selective stalling of human translation through small-molecule engagement of the ribosome nascent chain

Proprotein convertase subtilisin/kexin type 9 (PCSK9) plays a key role in regulating the levels of plasma low-density lipoprotein cholesterol (LDL-C). Here, we demonstrate that the compound PF-06446846 inhibits translation of PCSK9 by inducing the ribosome to stall around codon 34, mediated by the sequence of the nascent chain within the exit tunnel. We further show that PF-06446846 reduces pla...

Critical 23S rRNA interactions for macrolide-dependent ribosome stalling on the ErmCL nascent peptide chain

The nascent peptide exit tunnel has recently been identified as a functional region of ribosomes contributing to translation regulation and co-translational protein folding. Inducible expression of the erm resistance genes depends on ribosome stalling at specific codons of an upstream open reading frame in the presence of an exit tunnel-bound macrolide antibiotic. The molecular basis for this t...