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Updated: Aug 8, 2026

Membrane Transport Processes Analyzed by a Highly Parallel Nanopore Chip System at Single Protein Resolution
Published on: August 16, 2016
A model for co-translational translocation: ribosome-regulated nascent polypeptide translocation at the
1Howard Hughes Medical Institute, Health Research, Inc. at the Wadsworth Center, Empire State Plaza, Albany, NY 12201-0509, USA.
Abstract:
The protein-conducting channel (PCC) must allow both the translocation of soluble polypeptide regions across, and the lateral partitioning of hydrophobic transmembrane helices (TMHs) into, the membrane. We have analyzed existing structures of ribosomes and ribosome-PCC complexes and observe conformational changes suggesting that the ribosome may sense and orient the nascent polypeptide and also facilitate conformational changes in the PCC, subsequently directing the nascent polypeptide into the appropriate PCC-mediated translocation mode. The PCC is predicted to be able to accommodate one central, consolidated channel or two segregated pores with different lipid accessibilities, which may enable the lipid-mediated partitioning of a TMH from one pore, while the other, aqueous, pore allows translocation of a hydrophilic polypeptide segment. Our hypothesis suggests a plausible mechanism for the transitioning of the PCC between different configurations.
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