Conformational change category listing 4 | Beckstein Lab

In a combined X-ray crystallography/biochemistry/molecular simulation study published in Nature we present the structure of the sodium/proton antiporter NapA in its outward facing conformation. Together with the inward facing conformation of the related transporter NhaA we can now understand the conformational changes required for the sodium/proton antiport mechanism.

Secondary transporters couple the free energy stored in an ionic gradient to the movement of solutes across the cell membrane. The coupling enables these transmembrane proteins to transport small molecules against their own concentration gradients. The transporters function by cycling between different conformational states in which access to the central binding site is switched from the extracellular solution to the intracellular compartment. Using experimental and computational approaches we could visualize for the first time how this process occurs for a secondary transporter.