1qoq
CRYSTAL STRUCTURE OF WILD-TYPE TRYPTOPHAN SYNTHASE COMPLEXED WITH INDOLE GLYCEROL PHOSPHATE
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OverviewOverview
We used freeze trapping to stabilize the Michaelis complex of wild-type, tryptophan synthase and the alpha-subunit substrate indole-3-glycerol, phosphate (IGP) and determined its structure to 1. 8 A resolution. In, addition, we determined the 1.4 A resolution structure of the complex with, indole-3-propanole phosphate (IPP), a noncleavable IGP analogue. The, interaction of the 3'-hydroxyl of IGP with the catalytic alphaGlu49 leads, to a twisting of the propane chain and to a repositioning of the indole, ring compared to IPP. Concomitantly, the catalytic alphaAsp60 rotates, resulting in a translocation of the COMM domain [betaGly102-betaGly189, for definition see Schneider et al. (1998) Biochemistry 37, 5394-5406] in, a direction opposite to the one in the IPP complex. This results in loss, of the allosteric sodium ion bound at the beta-subunit and an opening of, the beta-active site, thereby making the cofactor pyridoxal 5'-phosphate, (PLP) accessible to solvent and thus serine binding. These findings form, the structural basis for the information transfer from the alpha- to the, beta-subunit and may explain the affinity increase of the beta-active site, for serine upon IGP binding.
About this StructureAbout this Structure
1QOQ is a Protein complex structure of sequences from Salmonella typhimurium with and as ligands. Active as Tryptophan synthase, with EC number 4.2.1.20 Known structural/functional Site: . Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of wild-type tryptophan synthase complexed with the natural substrate indole-3-glycerol phosphate., Weyand M, Schlichting I, Biochemistry. 1999 Dec 14;38(50):16469-80. PMID:10600108
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