TY - JOUR TI - Gradual compaction of the nascent peptide during cotranslational folding on the ribosome AU - Liutkute, Marija AU - Maiti, Manisankar AU - Samatova, Ekaterina AU - Enderlein, Jörg AU - Rodnina, Marina V A2 - Hegde, Ramanujan S A2 - Wolberger, Cynthia VL - 9 PY - 2020 DA - 2020/10/27 SP - e60895 C1 - eLife 2020;9:e60895 DO - 10.7554/eLife.60895 UR - https://doi.org/10.7554/eLife.60895 AB - Nascent polypeptides begin to fold in the constrained space of the ribosomal peptide exit tunnel. Here we use force-profile analysis (FPA) and photo-induced energy-transfer fluorescence correlation spectroscopy (PET-FCS) to show how a small -helical domain, the N-terminal domain of HemK, folds cotranslationally. Compaction starts vectorially as soon as the first -helical segments are synthesized. As nascent chain grows, emerging helical segments dock onto each other and continue to rearrange at the vicinity of the ribosome. Inside or in the proximity of the ribosome, the nascent peptide undergoes structural fluctuations on the µs time scale. The fluctuations slow down as the domain moves away from the ribosome. Mutations that destabilize the packing of the domain’s hydrophobic core have little effect on folding within the exit tunnel, but abolish the final domain stabilization. The results show the power of FPA and PET-FCS in solving the trajectory of cotranslational protein folding and in characterizing the dynamic properties of folding intermediates. KW - cotranslational folding KW - nascent chain dynamics KW - PET-FCS KW - HemK KW - ribosome JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER - 管家婆期期准免费资料精选