Title: Microscopes: Applications to Ion Channels

Speaker： Dr. Chen Song

             Department of Biochemistry, University of Oxford

Time： 1:00pm April 13th 2015

Address： Rm 102, East wing of Old Chemistry Building, Peking Unversity 

Chair：  Prof. Luhua Lai,  Center for Quantitative Biology 

Abstract：

     Theoretical and computational methods have been widely used in biological studies, and have been proven to be able to act as “computational microscopes” in many cases. Recently, using multi-scale computational microscopes, we observed some very interesting yet unexpected phenomena in our studies on potassium ion channels. Potassium ion channels are one kind of the most widely distributed membrane proteins and play fundamental biological roles by conducting potassium ions in a rapid and selective way. It was believed that, when the channel is open and activated, potassium ions and water molecules alternately occupy the four binding sites of the selectivity filter and permeate collectively. However, our latest multi-scale simulations indicate that this model cannot yield measurable conductance under physiologically relevant trans-membrane potential. Instead, the rapid ion permeation only occurs when there are no water molecules in the selectivity filter and potassium ions form direct contacts. This has been partially confirmed by the revisit to the previous X-ray crystallography data. Therefore, we propose a water-free knock-on mechanism for ion permeation in potassium channels.