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Publication Abstract from PubMed

Backbone assignments for the isolated alpha-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 alpha-subunit in the full TS alphabetabetaalpha bi-enzyme complex and to two new X-ray crystal structures of the isolated TS alpha-subunit reported in this work.

Backbone assignments and conformational dynamics in the S. typhimurium tryptophan synthase alpha-subunit from solution-state NMR.,Sakhrani VV, Hilario E, Caulkins BG, Hatcher-Skeers ME, Fan L, Dunn MF, Mueller LJ J Biomol NMR. 2020 Jul;74(6-7):341-354. doi: 10.1007/s10858-020-00320-2. Epub, 2020 May 15. PMID:32415580^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.