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

AtoE of E. coli has been examined topologically (Daley et al., 2005). It may transport short chain fatty acids into the E. coli cell (Salanitro and Wegener, 1971) although experimental characterisation is lacking.   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duplication followed by selective loss of genetic material in some organisms has occurred (T.E. Verlhac and M.H. Saier, unpublished results).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)



Daley, D.O., M. Rapp, E. Granseth, K. Melen, D. Drew, and G. von Heijne. (2005). Global topology analysis of the Escherichia coli inner membrane proteome. Science 308: 1321-1323.

Jenkins, L.S. and W.D. Nunn. (1987). Genetic and molecular characterization of the genes involved in short-chain fatty acid degradation in Escherichia coli: the ato system. J. Bacteriol. 169: 42-52.

Matta, M.K., E.E. Lioliou, C.H. Panagiotidis, D.A. Kyriakidis, and C.A. Panagiotidis. (2007). Interactions of the antizyme AtoC with regulatory elements of the Escherichia coli atoDAEB operon. J. Bacteriol. 189: 6324-6332.

Salanitro, J.P. and W.S. Wegener. (1971). Growth of Escherichia coli on short-chain fatty acids: nature of the uptake system. J. Bacteriol. 108: 893-901.


TC#NameOrganismal TypeExample

Short chain C4 - C6) fatty acid uptake permease, AtoE.  Encoded in the atoDAEB operon which is inducible by exogenous acetoacetate but not by other saturated short chain fatty acids such as butyrate and valerate (Jenkins and Nunn 1987; Matta et al. 2007). 


AtoE of E. coli (P76460)


Putative short chain fatty acid (SCFA) transporter of 464 aas and 12 TMSs.


SCFA transporter of Natronococcus occultus


Putative SCFA transporter of 471 aas


SCFA transporter of Halopiger xanaduensis