10.1021/nn303900y.s001
Pratik Raj Singh
Pratik Raj
Singh
Iván Bárcena-Uribarri
Iván
Bárcena-Uribarri
Niraj Modi
Niraj
Modi
Ulrich Kleinekathöfer
Ulrich
Kleinekathöfer
Roland Benz
Roland
Benz
Mathias Winterhalter
Mathias
Winterhalter
Kozhinjampara R Mahendran
Kozhinjampara R
Mahendran
Pulling Peptides across Nanochannels: Resolving Peptide Binding and Translocation through the Hetero-oligomeric Channel from <i>Nocardia farcinica</i>
American Chemical Society
2012
peptide binding
cationic peptides
peptide binding kinetics
Resolving Peptide Binding
2012-12-21 00:00:00
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Pulling_Peptides_across_Nanochannels_Resolving_Peptide_Binding_and_Translocation_through_the_Hetero_oligomeric_Channel_from_i_Nocardia_farcinica_i_/2458330
We investigated translocation of cationic peptides through nanochannels derived from the Gram-positive bacterium <i>Nocardia farcinica</i> at the single-molecule level. The two subunits NfpA and NfpB form a hetero-oligomeric cation selective channel. On the basis of amino acid comparison we performed homology modeling and obtained a channel structurally related to MspA of <i>Mycobacterium smegmatis</i>. The quantitative single-molecule measurements provide an insight into transport processes of solutes through nanochannels. High-resolution ion conductance measurements in the presence of peptides of different charge and length revealed the kinetics of peptide binding. The observed asymmetry in peptide binding kinetics indicated a unidirectional channel insertion in the lipid bilayer. In the case of cationic peptides, the external voltage acts as a driving force that promotes the interaction of the peptide with the channel surface. At low voltage, the peptide just binds to the channel, whereas at higher voltage, the force is strong enough to pull the peptide across the channel. This allows distinguishing quantitatively between peptide binding and translocation through the channel.