De novo design of a transmembrane Zn2+-transporting four-helix bundle.
Joh, N.H., Wang, T., Bhate, M.P., Acharya, R., Wu, Y., Grabe, M., Hong, M., Grigoryan, G., DeGrado, W.F.(2014) Science 346: 1520-1524
- PubMed: 25525248 
- DOI: https://doi.org/10.1126/science.1261172
- Primary Citation of Related Structures:  
2MUZ, 4P6J, 4P6K, 4P6L - PubMed Abstract: 
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.
Organizational Affiliation: 
Department of Pharmaceutical Chemistry, Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94158, USA.