Allosteric effects acting over a distance of 20-25 A in the Escherichia coli tryptophan synthase bienzyme complex increase ligand affinity and cause redistribution of covalent intermediates.

The reactions of L-histidine (L-His) and L-tryptophan (L-Trp) with the alpha 2 beta 2 complex of Escherichia coli tryptophan synthase are introduced as probes both of beta-subunit catalysis and of ligand-mediated alpha-beta allosteric interactions. Binding of DL-alpha-glycerol 3-phosphate (GP), an analogue of 3-indole-D-glycerol 3'-phosphate (IGP), to the… CONTINUE READING