De novo design of a transmembrane Zn²⁺-transporting four-helix bundle.
Publication Type:Journal Article
Source:Science, Volume 346, Issue 6216, p.1520-4 (2014)
Keywords:Carrier Proteins, Crystallography, X-Ray, Ion Transport, Lipid Bilayers, Membrane Proteins, Micelles, Molecular Dynamics Simulation, Protein Engineering, Protein Structure, Secondary, Zinc
<p>The design of functional membrane proteins from first principles represents a grand challenge in chemistry and structural biology. Here, we report the design of a membrane-spanning, four-helical bundle that transports first-row transition metal ions Zn(2+) and Co(2+), but not Ca(2+), across membranes. The conduction path was designed to contain two di-metal binding sites that bind with negative cooperativity. X-ray crystallography and solid-state and solution nuclear magnetic resonance indicate that the overall helical bundle is formed from two tightly interacting pairs of helices, which form individual domains that interact weakly along a more dynamic interface. Vesicle flux experiments show that as Zn(2+) ions diffuse down their concentration gradients, protons are antiported. These experiments illustrate the feasibility of designing membrane proteins with predefined structural and dynamic properties. </p>