Sandbox Reserved 969: Difference between revisions
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== '''The Filter Selectivity''' == | == '''The Filter Selectivity''' == | ||
The filter is defined by a <scene name='60/604488/Highly_conserved_sequence/1'>highly conserved amino acid sequence T(63)VGDG(67)</scene> that’s why the channel is selective for some cations like K+ or Na+. The [http://en.wikipedia.org/wiki/Potassium_channel#Selectivity_filter'''selectivity filter'''] has the same conformation in low K+/high Na+ or high K+/low Na+ concentrations. So the concentration does not impact the conformation of the filter but it can adopt 2 different structures : a '''conductive state''' and a '''non conductive state'''. In fact, some '''hydrogen bonds''' are important for the stability of the NaK selectivity filter and the balance between the 2 structures. For example, an hydrogen bond between residues <scene name='60/604488/Asp_66/1'>Asp 66</scene> and <scene name='60/604488/Asn_68/1'>Asn 68</scene> stabilize the non conductive state whereas an hydrogen bond between Asp | The filter is defined by a <scene name='60/604488/Highly_conserved_sequence/1'>highly conserved amino acid sequence T(63)VGDG(67)</scene> that’s why the channel is selective for some cations like K+ or Na+. The [http://en.wikipedia.org/wiki/Potassium_channel#Selectivity_filter'''selectivity filter'''] has the same conformation in low K+/high Na+ or high K+/low Na+ concentrations. So the concentration does not impact the conformation of the filter but it can adopt 2 different structures : a '''conductive state''' and a '''non conductive state'''. In fact, some '''hydrogen bonds''' are important for the stability of the NaK selectivity filter and the balance between the 2 structures. For example, an hydrogen bond between residues <scene name='60/604488/Asp_66/1'>Asp 66</scene> and <scene name='60/604488/Asn_68/1'>Asn 68</scene> stabilize the non conductive state whereas an hydrogen bond between <scene name='60/604488/Asp_66/1'>Asp 66</scene> and Tyr-55 stabilize the conductive state. The change between the 2 structures are very fast. | ||
The conductive state is characterized by a '''low energy barrier'''. In contrast, a non conductive state is characterized by '''high energy barrier'''. | The conductive state is characterized by a '''low energy barrier'''. In contrast, a non conductive state is characterized by '''high energy barrier'''. | ||
