Quantitative Imaging of the Electrostatic Field and Potential Generated by a Transmembrane Protein Pore at Subnanometer Resolution
| Autor: | Daniel J. Müller, Ulf Hensen, Moritz Pfreundschuh |
|---|---|
| Rok vydání: | 2013 |
| Předmět: |
Static Electricity
Porins Bioengineering Nanotechnology 02 engineering and technology Microscopy Atomic Force 03 medical and health sciences Static electricity Native state Molecule General Materials Science Surface charge 030304 developmental biology Ions 0303 health sciences Chemistry Mechanical Engineering Membrane Proteins General Chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics Electrostatics Transmembrane protein 3. Good health Characterization (materials science) Nanopore Biophysics 0210 nano-technology |
| Zdroj: | Nano Letters |
| ISSN: | 1530-6992 1530-6984 |
| Popis: | Elucidating the mechanisms by which proteins translocate small molecules and ions through transmembrane pores and channels is of great interest in biology, medicine, and nanotechnology. However, the characterization of pore forming proteins in their native state lacks suitable methods that are capable of high-resolution imaging (~1 nm) while simultaneously mapping physical and chemical properties. Here we report how force-distance (FD) curve-based atomic force microscopy (AFM) imaging can be applied to image the native pore forming outer membrane protein F (OmpF) at subnanometer resolution and to quantify the electrostatic field and potential generated by the transmembrane pore. We further observe the electrostatic field and potential of the OmpF pore switching "on" and "off" in dependence of the electrolyte concentration. Because electrostatic field and potential select for charged molecules and ions and guide them to the transmembrane pore the insights are of fundamental importance to understand the pore function. These experimental results establish FD-based AFM as a unique tool to image biological systems to subnanometer resolution and to quantify their electrostatic properties. |
| Databáze: | OpenAIRE |
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