Chemical-Induced pH-Mediated Molecular Switch

The transmembrane protein a-hemolysin pore has been used to develop ultrasensitive biosensors, study biomolecular folding and unfolding, investigate covalent and noncovalent bonding interactions, and probe enzyme kinetics. Here, we report that, by addition of ionic liquid tetrakis-(hydroxymethyl)phosphonium chloride solution to the alpha-hemolysin pore, the alpha-hemolysin channel can be controlled open or closed by adjusting the pH of the solution. This approach can be employed to develop a novel molecular switch to regulate molecular transport and should find potential applications as a smart drug delivery method.