Answer
Symporter and antiporter
Work Step by Step
The protein described:
- Has two binding sites (A and B).
- Can switch conformations so that both sites are exposed to only one side of the membrane at a time.
- Conformational change occurs only when both sites are occupied or both are empty.
This describes a coupled transporter, specifically a carrier protein that operates via an alternating access mechanism. The key feature is that it only switches conformation when both binding sites are either occupied or empty, which prevents partial transport and ensures strict coupling between solute A and solute B.
This behavior is characteristic of symporters and antiporters, which move two solutes together in a coordinated fashion.
