A molecular model of the AEKA motif of the selectivity filter of the Na⁺ channel in a steady-state configuration formed by MD simulation with the Na⁺ ion inside. I-IV P loops are shown by green ribbons, residues of AEKA by space-filled images, Na⁺ by a pink ball. During MD simulation the Na⁺ ion interacts with oxygens of glutamate(II), losing one water of hydration and easily breaking its initial hydrogen bond with lysine(III).