Trigger Factor Flexibility

A nuclear magnetic resonance study shows how the bacterial chaperone trigger factor can dynamically bind and release many different substrates. [Also see Research Article by Saio et al.] Molecular chaperones are found in all cells and are essential for maintaining a functional proteome. The main function of chaperones is to promote correct protein folding by protecting non-native proteins from folding along pathways that lead to protein misfolding and aggregation. To fulfill this task, chaperones must recognize a non-native protein, transiently bind to it, and then release it at precisely the right time to allow the substrate to proceed with its folding course. Many but not all chaperones use adenosine 5′-triphosphate (ATP) to control the dynamic substrate binding and release cycle (1). On page 597 of this issue, Saio et al. (2) unravel the structural basis and underlying mechanism of action of the ATP-independent chaperone trigger factor (TF).