ECF239

ECF subgroups

ECF239s1 91 ECF239s2 47 ECF239s3 44 ECF239s4 32 ECF239s5 25 ECF239s6 19 ECF239s7 12 ECF239s8 16 ECF239s9 10

ECF proteins

General description: This is a FecI-like group whose proteins have homology to the original group ECF10 (95.18%), although this is not the largest ECF10-like group. The proteins in ECF239 are mainly present in Bacteroidetes (99.22%) mostly from family Flavobacteriaceae.

Regulation and function: The genetic context of members of ECF239 follow the rule of FecI-like ECFs, with a FecR-like single TM helix AS factor in +1 and an outer-membrane TonB-dependent receptor in +2 (Staroń et al., 2009). The FecR-like AS factor is fused to a DUF4974 domain (except ECF239s9), as in other FecR-like proteins, and contain one TM helix (96.88%). The TonB-dependent receptor might be fused to a carboxypeptidase regulatory-like domain (Pfam: CarbopepD_reg_2) of unknown function, and it is predicted to be a β-barrel outer membrane protein. In the FecI system of E. coli, this outer-membrane protein is FecA, a TonB-dependent transporter of ferric citrate across the outer membrane (reviewed in (Braun & Mahren, 2005)). Members of original ECF10 are suggested to transport carbohydrates across the membrane since their genetic neighborhood contains an outer membrane protein homolog of the polysaccharide-binding proteins SusC and SusD (Staroń et al., 2009). Nevertheless, despite being part of original ECF10, members of ECF239 lack of this carbohydrate binding protein.

Genomic context conservation: Other conserved proteins are only present in ECF239s3 and include an SRP54-type protein (-2), a tetrahydrofolate dehydrogenase/cyclohydrolase (-3), an amidinotransferase, a glyoxalase/bleomycin resistance protein/dioxygenase superfamily and an arginyl tRNA synthetase.

Promoter motif conservation: Predicted target promoter motifs often (6/9) contain a conserved (A|G)ACA in -35 and a TAC in -10. It is possible that members of ECF239 are autoregulated, a new feature for a FecI-like group (Staroń et al., 2009).

Summary: ECF239 contains sequences with homology to the original group ECF10. However, unlike original ECF10 (Staroń et al., 2009), AS factors from ECF239 do not contain a carbohydrate-binding domain in their genetic context and contain conserved target promoter motifs, indicating autoregulation.