Download MendeleyBackbone assignments and conformational dynamics in the S. typhimurium tryptophan synthase alpha-subunit from solution-state NMR.
Sakhrani, V.V., Hilario, E., Caulkins, B.G., Hatcher-Skeers, M.E., Fan, L., Dunn, M.F., Mueller, L.J.(2020) J Biomol NMR 74: 341-354
- PubMed: 32415580
- DOI: https://doi.org/10.1007/s10858-020-00320-2
- Primary Citation of Related Structures:
6OSO, 6OUY - PubMed Abstract:
Backbone assignments for the isolated α-subunit of Salmonella typhimurium tryptophan synthase (TS) are reported based on triple resonance solution-state NMR experiments on a uniformly 2 H, 13 C, 15 N-labeled sample. From the backbone chemical shifts, secondary structure and random coil index order parameters (RCI-S 2 ) are predicted. Titration with the 3-indole-D-glycerol 3'-phosphate analog, N-(4'-trifluoromethoxybenzenesulfonyl)-2-aminoethyl phosphate (F9), leads to chemical shift perturbations indicative of conformational changes from which an estimate of the dissociation constant is obtained. Comparisons of the backbone chemical-shifts, RCI-S 2 values, and site-specific relaxation times with and without F9 reveal allosteric changes including modulation in secondary structures and loop rigidity induced upon ligand binding. A comparison is made to the X-ray crystal structure of the α-subunit in the full TS αββα bi-enzyme complex and to two new X-ray crystal structures of the isolated TS α-subunit reported in this work.
Organizational Affiliation:
Department of Chemistry, University of California Riverside, Riverside, CA, 92521, USA.
