Journal article
Dynamics and Energy Contributions for Transport of Unfolded Pertactin through a Protein Nanopore
ACS nano, Vol.9(9), pp.9050-9061
09/22/2015
DOI: 10.1021/acsnano.5b03053
PMCID: PMC4835817
PMID: 26302243
Abstract
To evaluate the physical parameters governing translocation of an unfolded protein across a lipid bilayer, we studied protein transport through aerolysin, a passive protein channel, at the single-molecule level. The protein model used was the passenger domain of pertactin, an autotransporter virulence protein. Transport of pertactin through the aerolysin nanopore was detected as transient partial current blockades as the unfolded protein partially occluded the aerolysin channel. We compared the dynamics of entry and transport for unfolded pertactin and a covalent end-to-end dimer of the same protein. For both the monomer and the dimer, the event frequency of current blockades increased exponentially with the applied voltage, while the duration of each event decreased exponentially as a function of the electrical potential. The blockade time was twice as long for the dimer as for the monomer. The calculated activation free energy includes a main enthalpic component that we attribute to electrostatic interactions between pertactin and the aerolysin nanopore (despite the low Debye length), plus an entropic component due to confinement of the unfolded chain within the narrow pore. Comparing our experimental results to previous studies and theory suggests that unfolded proteins cross the membrane by passing through the nanopore in a somewhat compact conformation according to the "blob" model of Daoud and de Gennes.
Details
- Title: Subtitle
- Dynamics and Energy Contributions for Transport of Unfolded Pertactin through a Protein Nanopore
- Creators
- Benjamin Cressiot - University of Notre Dame [Indiana]Esther Braselmann - University of Notre Dame [Indiana]Abdelghani Oukhaled - Laboratoire Analyse et Modélisation pour la Biologie et l'EnvironnementAdrian H Elcock - University of Iowa [Iowa City]Juan Pelta - Laboratoire Analyse et Modélisation pour la Biologie et l'EnvironnementPatricia L Clark - University of Notre Dame [Indiana]
- Resource Type
- Journal article
- Publication Details
- ACS nano, Vol.9(9), pp.9050-9061
- DOI
- 10.1021/acsnano.5b03053
- PMID
- 26302243
- PMCID
- PMC4835817
- NLM abbreviation
- ACS Nano
- ISSN
- 1936-0851
- eISSN
- 1936-086X
- Publisher
- American Chemical Society
- Grant note
- name: R?gion ?le-de-France, award: 094251; DOI: 10.13039/501100001665, name: Agence Nationale de la Recherche, award: ANR 12-NANO-0012-03; DOI: 10.13039/100000057, name: National Institute of General Medical Sciences, award: R01 GM097573, T32 GM075762, U54 GM105816
- Language
- English
- Date published
- 09/22/2015
- Academic Unit
- Physics and Astronomy; Biochemistry and Molecular Biology
- Record Identifier
- 9984024534802771
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