Charge-driven dynamics of nascent-chain movement through the SecYEG translocon.

ABSTRACT: On average, every fifth residue in secretory proteins carries either a positive or a negative charge. In a bacterium such as Escherichia coli, charged residues are exposed to an electric field as they transit through the inner membrane, and this should generate a fluctuating electric force on a translocating nascent chain. Here, we have used translational arrest peptides as in vivo force sensors to measure this electric force during cotranslational chain translocation through the SecYEG translocon. We find that charged residues experience a biphasic electric force as they move across the membrane, including an early component with a maximum when they are 47-49 residues away from the ribosomal P site, followed by a more slowly varying component. The early component is generated by the trans

SUBMITTER: Ismail N 

PROVIDER: S-EPMC4338579 | biostudies-literature | 2015 Feb

REPOSITORIES: biostudies-literature