Interactions of peptides with a protein pore.

ABSTRACT: The partitioning of polypeptides into nanoscale transmembrane pores is of fundamental importance in biology. Examples include protein translocation in the endoplasmic reticulum and the passage of proteins through the nuclear pore complex. Here we examine the exchange of cationic alpha-helical peptides between the bulk aqueous phase and the transmembrane beta-barrel of the alpha-hemolysin (alphaHL) protein pore at the single-molecule level. The experimental kinetic data suggest a two-barrier, single-well free energy profile for peptide transit through the alphaHL pore. This free energy profile is strongly voltage- and peptide-length-dependent. We used the Woodhull-Eyring formalism to rationalize the values measured for the association and dissociation rate constants k(on) and k(off), and to

SUBMITTER: Movileanu L 

PROVIDER: S-EPMC1366589 | biostudies-literature | 2005 Aug

REPOSITORIES: biostudies-literature