Berlin 2008 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 9: Membranes and Interfaces
BP 9.3: Vortrag
Dienstag, 26. Februar 2008, 11:00–11:15, PC 203
Transport at nanoscale revealed by the temperature dependence of ion conductance — •Catalin Chimerel1, Liviu Movileanu2, Ulrich Kleinekathöfer1, and Mathias Winterhalter1 — 1Jacobs University Bremen, Bremen, Germany — 2Syracuse University, Syracuse, New York, USA
Temperature dependent ion conductance in nanopores is measured in a wide range of electrolyte concentration and compared with molecular modeling. Single outer membrane protein F (OmpF) channels from E. coli are reconstituted into planar lipid bilayers. In a qualitative agreement with the experimental data, applied field molecular dynamics revealed atomistic details of the charge transport in the studied nanopore. Comparing the temperature dependence of the channel conductance with that of the bulk electrolyte conductivity in the range from 0°C to 72°C revealed that at low salt concentration the charge transport is mainly driven along the pore surface. Increasing the salt concentration saturates the surface charge transport and induces charge transport in the center of the nanopore. Opposite to the surface transport, the transport in the nanopore center favors the formation of ion pairs. Increasing the salt concentration increases the ion pair formation in the nanopore faster than in the bulk, therefore an increase in salt concentration leads to a slower increase in the nanopore conductance compared to the bulk conductivity. Increasing the temperature reduces the life time of the ion pairs and leads to a faster increase in channel conductance compared to the bulk conductivity.