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Shixin Xu

2013-12-26
14:20:00 - 15:10:00

101 , Mathematics Research Center Building (ori. New Math. Bldg.)

Gramicidin A is a small well characterized peptide that forms an ion channel (transmembrane protein) in lipid membranes. An important feature of gramicidin A (gA) pore is that its conductance is affected by the electric charges near the entrance of the gramicidin A pore. This properly has led to the application of gramicidin A as a biochemical sensor for monitoring and quantifying a number of chemical and enzymatic reactions. Here, a mathematical model of conductance changes of gramicidin A pores in response to the presence of electrical charges near its entrance, either on membrane surface or attached to gramicidin A itself, is presented. In this numerical simulation, a two dimensional computational domain is set to mimic the structure of a gramicidin A channel in the bilayer surrounded by electrolyte. The transportation of ions through the channel is modelled by the Poisson-Nernst-Planck (PNP) equations that are solved by Finite Element Method (FEM). Preliminary numerical simulations of this mathematical model are in qualitatively agreement with the experimental results in the literatures.