2.A.73 The Short Chain Fatty Acid Uptake (AtoE) Family

AtoE of E. coli has been examined functionally and topologically (Daley et al., 2002). It may transport short chain fatty acids into the E. coli cell (Salanitro and Wegener, 1971). Members of the AtoE derive from proteobacteria of the α-, β-, γ-, δ- and ε-subgroups, Bacteroidetes, Fusobacteria, Acidobacteria, Firmicutes, Actinobacteria and Archaea. They are of fairly uniform size (425-487 aas). Topological analyses of AtoE family members suggest 10 TMSs in a 5 + 5 arrangement. Phylogenetic analyses indicate that AtoE family members are diverse in function with several non-orthologous sets. Further, the tree suggests either that horizontal transfer or early gene duplication followed by selective loss of genetic material in some organisms has occurred (T.E. Verlhac and M.H. Saier, unpublished results).

The reaction presumed to be catalyzed by AtoE is:

short chain fatty acid (out) + H⁺ (out) → short chain fatty acid (in) + H⁺ (in)