This group dissipated from the ECF classification during the reclassification by [[Casas-Pastor et al.]]!
ECF49 σ factors were only identified in genomes of organisms belonging to the phylum Actinobacteria (Huang et al., 2015).
In this group, the genomic context conservation does not extend beyond the genes encoding the σ/anti-σ pair (Huang et al., 2015).
The ECF49 anti-σ factors are predicted transmembrane proteins with a weak similarity to ECF19 anti-σ factors (Huang et al., 2015). Nothing is known about the mechanism underlying ECF49 σ factor activation.
This group is present in new ECF218 together with original groups ECF47 and ECF50. 33.49% of the proteins from ECF218 have homology to original ECF49.