Display Settings:

Format

Send to:

Choose Destination

    ACS Chem Biol. 2008 Sep 19;3(9):555-66. Epub 2008 Aug 22.

    Chain dynamics of nascent polypeptides emerging from the ribosome.

    Ellis JP, Bakke CK, Kirchdoerfer RN, Jungbauer LM, Cavagnero S.

    Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, USA.

    Comment in:

    Very little is known about the conformation of polypeptides emerging from the ribosome during protein biosynthesis. Here, we explore the dynamics of ribosome-bound nascent polypeptides and proteins in Escherichia coli by dynamic fluorescence depolarization and assess the population of cotranslationally active chaperones trigger factor (TF) and DnaK. E. coli cell-free technology and fluorophore-linked E. coli Met-tRNA f Met enable selective site-specific labeling of nascent proteins at the N-terminal methionine. For the first time, direct spectroscopic evidence captures the generation of independent nascent chain motions for a single-domain protein emerging from the ribosome (apparent rotational correlation time approximately 5 ns), during the intermediate and late stages of polypeptide elongation. Such motions are detected only for a sequence encoding a globular protein and not for a natively unfolded control, suggesting that the independent nascent chain dynamics may be a signature of folding-competent sequences. In summary, we observe multicomponent, severely rotationally restricted, and strongly chain length/sequence-dependent nascent chain dynamics.

    PMID: 18717565 [PubMed - indexed for MEDLINE]

    PMCID: 2572860

    Supplemental Content

    Click here to read Click here to read Click here to read