Mutation of his-157 in the second pore loop drastically reduces the activity of the Synechocystis Ktr-type transporter

Mutation of a conserved His-157 in the second pore loop of KtrB drastically reduced the activity of the K+ transporter from Synechocystis sp. strain PCC 6803. This result suggests that His-157 plays an essential role in the K+ transport activity of the transporter system.