This group dissipated from the ECF classification during the reclassification by [[Casas-Pastor et al.]]!
This group is restricted to Actinobacteria (Huang et al., 2015).
σ factors of this group are putatively co-transcribed with their cognate anti-σ factors but the genomic context conservation does not go beyond the σ/anti-σ pair (Huang et al., 2015).
These anti-σ factors are predicted membrane-spanning proteins that contain an N-terminal ASD and show a weak similarity to M. tuberculosis RskA (regulator of SigK, which belongs to group ECF19) (Huang et al., 2015). No further details are available regarding the molecular mechanism controlling the activation of ECF47 σ factors.
This group is present in new ECF218 together with original groups ECF49 and ECF50. 29.27% of the proteins from ECF218 have homology to original ECF47.