Physical model for the gating mechanism of ionic channels.
We propose a physical model for the gating mechanism of ionic channels. First, we investigate the fluctuation-mediated interactions between two proteins imbedded in a cellular membrane and find that the interaction depends on their orientational configuration as well as the distance between them. The orientational dependence of interactions arises from the fact that the noncircular cross-sectional shapes of individual proteins constrain fluctuations of the membrane differently according to their orientational configuration. Then, we apply these interactions to ionic channels composed of four, five, and six proteins. As the gating stimulus creates the changes in the structural shape of proteins composing ionic channels, the orientational configuration of the ionic channels changes due to the free energy minimization, and ionic channels are open or closed according to the conformation thereof.
Ghim
Cheol-Min
CM
School of Physics, Seoul National University, Korea.
Park
Jeong-Man
JM
D055592:Biophysical Phenomena; D001703:Biophysics; D015640:Ion Channel Gating / Q000502:physiology*; D007473:Ion Channels / Q000737:chemistry; D046911:Macromolecular Substances; D008565:Membrane Proteins / Q000737:chemistry; D008954:Models, Biological; D011487:Protein Conformation; D013816:Thermodynamics
D007473:Ion Channels; D046911:Macromolecular Substances; D008565:Membrane Proteins