Does the lipid environment impact the open-state conductance of an engineered beta-barrel protein nanopore?

作者：Tomita Noriko; Mohammad Mohammad M; Niedzwiecki David J; Ohta Makoto; Movileanu Liviu^*

来源：Biochimica et Biophysica Acta-Biomembranes, 2013, 1828(3): 1057-1065.

DOI：10.1016/j.bbamem.2012.12.003

• E. coli FhuA
• Planar lipid bilayer
• Dimensionless shape factor
• Channel closure
• Single-channel recording
• Lipid effect

Using rational membrane protein design, we were recently able to obtain a beta-barrel protein nanopore that was robust under an unusually broad range of experimental circumstances. This protein nanopore was based upon the native scaffold of the bacterial ferric hydroxamate uptake component A (FhuA) of Escherichia coli. In this work, we expanded the examinations of the open-state current of this engineered protein nanopore, also called FhuA Delta C/Delta 4L, employing an array of lipid bilayer systems that contained charged and uncharged as well as conical and cylindrical lipids. Remarkably, systematical single-channel analysis of FhuA Delta C/Delta 4L indicated that most of its biophysical features, such as the unitary conductance and the stability of the open-state current were not altered under the conditions tested in this work. However, electrical recordings at high transmembrane potentials revealed that the presence of conical phospholipids within the bilayer catalyzes the first, stepwise current transition of the FhuA Delta C/Delta 4L protein nanopore to a lower-conductance open state. This study reinforces the stability of the open-state current of the engineered FhuA Delta C/Delta 4L protein nanopore under various experimental conditions, paving the way for further critical developments in biosensing and molecular biomedical diagnosis.

• 出版日期2013-3