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).
In this group the genomic context conservation does not go beyond the genes coding for the σ/anti-σ proteins (Huang et al., 2015).
Except for the presence of a putative membrane-associated anti-σ factor nothing is known about the mechanisms by which these σ factors are activated.
This group is present in new ECF218 together with original groups ECF47 and ECF49. 28.48% of the proteins from ECF218 have homology to original ECF50.