Zinc inhibition of monomeric and dimeric proton channels suggests cooperative gating

What is it about?

We compare the properties of monomeric vs. dimeric proton channels. Zn2+ was thought to inhibit proton currents by binding competitively with protons at 2 His residues (Cherny & DeCoursey, 1999). In the earliest model of a monomer, the two His are too far apart. Here we find evidence that Zn2+ is coordinated between His at the interface between monomers. Recently the crystal structure of mHV1 has a Zn bound within a monomer (Takeshita et al, 2014). Either the model was wrong, or the open-state model differs from the closed-state structure.

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