An obligatory intermediate controls the folding of the alpha-subunit of tryptophan synthase, a TIM barrel protein
Wintrode, P.L.; Rojsajjakul, T.; Vadrevu, R.; Matthews, C.Robert.; Smith, D.L.
Journal of Molecular Biology 347(5): 911-919
The proposed kinetic folding mechanism of the alpha-subunit of tryptophan Western synthase (alpha TS), a TIM barrel protein, displays multiple unfolded and intermediate forms which fold through four parallel pathways to reach the native state. To obtain insight into the secondary structure that stabilizes a set of late, highly populated kinetic intermediates, the refolding of urea-denatured alpha TS. from Escherichia coli was monitored by pulse-quench hydrogen exchange mass spectrometry.