The plasticity of a translation arrest motif yields insights into nascent polypeptide recognition inside the ribosome tunnel.

ABSTRACT: The recognition of a C-terminal motif in E. coli SecM ((150)FXXXXWIXXXXGIRAGP(166)) inside the ribosome tunnel causes translation arrest, but the mechanism of recognition is unknown. Whereas single mutations in this motif impair recognition, we demonstrate that new arrest-inducing peptides can be created through remodeling of the SecM C terminus. We found that R163 is indispensable but that flanking residues that vary in number and position play an important secondary role in translation arrest. The observation that individual SecM variants showed a distinct pattern of crosslinking to ribosomal proteins suggests that each peptide adopts a unique conformation inside the tunnel. Based on the results, we propose that translation arrest occurs when the peptide conformation specified by flankin

SUBMITTER: Yap MN 

PROVIDER: S-EPMC2704006 | biostudies-literature | 2009 Apr

REPOSITORIES: biostudies-literature