Table 1. Sequence-based function prediction for ancestors of Ffh, FtsY, and SecY.

Protein	Inferred Origin	PFAM (alignment locus|e-value)	Protein localization based on SOSUI (hydrophobicity index)
Ancestral Ffh/FtsY	pre-LUCA	SRP54-type protein, helical bundle domain (6–81|1.4e-76) SRP54-type protein, GTPase domain (95–279|1.7e-15)	cytoplasmic (0.0792)
Ffh	LUCA	SRP54-type protein, helical bundle domain (5–80|8.0e-21) SRP54-type protein, GTPase domain (94–278|1.3e-77) Signal peptide binding domain (309–408|8.7e-43)	cytoplasmic (-0.3597)
FtsY	LUCA	SRP54-type protein, helical bundle domain (96–175|7.2e-11) SRP54-type protein, GTPase domain (189–373| 1.6e-76)	cytoplasmic (-0.4542)
SecY	LUCA	SecY translocase (58–377|4.9e-101)	trans-membrane(0.9908)