Mutational widening of constrictions in a formate-nitrite/H⁺ transporter enables aquaporin-like water permeability and proton conductance.

ABSTRACT: The unrelated protein families of the microbial formate-nitrite transporters (FNTs) and aquaporins (AQP) likely adapted the same protein fold through convergent evolution. FNTs facilitate weak acid anion/H⁺ cotransport, whereas AQP water channels strictly exclude charged substrates including protons. The FNT channel-like transduction pathway bears two lipophilic constriction sites that sandwich a highly conserved histidine residue. Because of lacking experiments, the function of these constrictions is unclear, and the protonation status of the central histidine during substrate transport remains a matter of debate. Here, we introduced constriction-widening mutations into the prototypical FNT from Escherichia coli, FocA, and assayed formate/H⁺ transport properties, wat

SUBMITTER: Schmidt JDR 

PROVIDER: S-EPMC8749060 | biostudies-literature | 2022 Jan

REPOSITORIES: biostudies-literature