Chaperones involved in assembly and export of N-oxide reductases.

Controlled targeting and transport of redox enzymes to and across the bacterial cytoplasmic membrane is essential for bacterial respiration. A subset of bacterial redox enzymes is exported as folded proteins on the Tat (twin-arginine transport) pathway. Protein export is the point-of-no-return for passenger proteins on the Tat pathway and it is crucial that complex, cofactor-containing enzymes are fully assembled before export is attempted. Using the Escherichia coli trimethylamine N-oxide reductase system as a model, we discuss here the molecular processes governing assembly and export of Tat-dependent enzymes.