TorD, an essential chaperone for TorA molybdoenzyme maturation at high temperature.

TorD has been recognized as an accessory protein that improves maturation of TorA, the molybdenum cofactor-containing trimethylamine oxide reductase of Escherichia coli. In this study, we show that at 42 degrees C and in the absence of TorD TorA is poorly matured and almost completely degraded. Strikingly, TorD restores TorA maturation to the same level whatever the growth temperature. In vitro experiments in which apoTorA was incubated with or without TorD at various temperatures confirm that TorD is an essential chaperone for TorA at elevated temperatures preventing apoTorA mis-folding before cofactor insertion.