Conformation of GroEL-bound α-lactalbumin probed by mass spectrometry

• DOI: 10.1038/372646a0
• Publication Date: 2003-08-12T01:23:35Z
• Authors: Carol V. Robinson; Michael Groß; Stephen J. Eyles; Jonathan J. Ewbank; Mark Mayhew; F. Ulrich Hartl; Christopher M. Do...; Sheena E. Radford
• Keywords: 0303 health sciences; Protein Conformation; Chaperonin 60; Mass Spectrometry; Kinetics; 03 medical and health sciences; Escherichia coli; Lactalbumin; Animals; Cattle; Disulfides; Hydrogen; Protein Binding

The conformation of a three-disulphide derivative of bovine alpha-lactalbumin bound to the molecular chaperone GroEL has been investigated by monitoring directly its hydrogen exchange kinetics using electrospray ionization mass spectrometry. The bound protein is weakly protected from exchange to an extent closely similar to that of an uncomplexed molten globule state of the three-disulphide protein. Binding to GroEL in this system appears to involve relatively disordered partly folded states resembling intermediates formed in the very early stages of kinetic folding of many proteins in vitro.