Sandbox Reserved 969: Difference between revisions
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=== Vestibule === | === Vestibule === | ||
In the case of the vestibule, there are too four carbonyl oxygen atom which brings by a valine (Val64). For instance, Na+ is neared to the ligand by this way: distance Na+-ligand=2,9 Ä. Moreover, ions are partially hydrated by four water molecules( they are along with the carboxyl oxygene atoms) : distance ions-H2O=4 Ä. The presence of water allows a greater flexibility in the ion binding so the vestibule may adapt to monovalent cations such as Na+, K+ and Rb+. However, this structure has a greater selectivity for K+ than Na+ : water molecules help to create a selectivity filter thanks to ligand geometry: octahedral arrangement which is impossible with Na+ because of a smaller radius and a hydratation by 5-6 molecules of water <ref> PMID: 16875774 </ref>. | In the case of the vestibule, there are too four carbonyl oxygen atom which brings by a valine (Val64). For instance, Na+ is neared to the ligand by this way: distance Na+-ligand=2,9 Ä. Moreover, ions are partially hydrated by four water molecules (they are along with the carboxyl oxygene atoms) : distance ions-H2O=4 Ä. The presence of water allows a greater flexibility in the ion binding so the vestibule may adapt to monovalent cations such as Na+, K+ and Rb+. However, this structure has a greater selectivity for K+ than Na+ : water molecules help to create a selectivity filter thanks to ligand geometry: octahedral arrangement which is impossible with Na+ because of a smaller radius and a hydratation by 5-6 molecules of water <ref> PMID: 16875774 </ref>. | ||
The nature of the ligands is '''carbonyl-water'''. | The nature of the ligands is '''carbonyl-water'''. | ||
