“…With the exception of S4, abolishment of the hydrogen bonding at S1 through S3 via directed mutagenesis significantly decreased acetate conduction (Supplementary information, Figure S8), suggesting an essential role of hydrogen bonding at S1, S2, and S3 for acetate transport. S1 binds a partially dehydrated acetate S1 is the only acetate-binding site among the four that binds a partially dehydrated acetate 35,36 (i.e., an acetate ion that is less than fully hydrated with water molecules) (Figs. 3a, 4a; Supplementary information, Figures S7 and 9).…”