Structure of the formate transporter FocA reveals a pentameric aquaporin-like channel

The formate–nitrite transporter family, of which FocA is a representative member, is known to transport short-chain acids in bacteria, archaea, fungi, algae and parasites; however, the structure and transport mechanism of these transporters remain unknown. Here, study of the crystal structure of Escherichia coli FocA reveals that the overall structure of FocA closely resembles that of aquaporin, suggesting that it is in fact a channel, rather than a transporter.