Constitutive expression of Escherichia coli tat genes indicates an important role for the twin-arginine translocase during aerobic and anaerobic growth

The transcription start sites for the tatABCD and tatE loci, encoding compo nents of the Tat (twin-arginine translocase) protein export pathway, have b een identified. Expression studies indicate that the tatABCD and tatE trans cription units are expressed constitutively. Translational fusion experimen ts suggest that Tati is synthesized at a much higher level than the other T at proteins.