Molecular chaperones and protein translocation across the Escherichia coli inner membrane

Abstract

Proteins that are able to translocate across biological membranes assume of loosely folded structure. In this review it is suggested that the loosely folded structure, referred to here as‘per‐folded conformation', is a particular structure that interacts favourably with components of the export apparatus. Two soluble factors, SecB and GroEL, have been implicated in maintenance of the pre‐folded conformation and have been termed‘molecular chaperones'. Results suggest that SecB may be a chaperone that is specialized for binding to exported protein precursors, while GroEL may be a general folding modulator that binds to many intracellular proteins.