1qoq
From Proteopedia
| |||||||
| , resolution 1.8Å | |||||||
|---|---|---|---|---|---|---|---|
| Sites: | |||||||
| Ligands: | and | ||||||
| Gene: | TRPA/TRPB (Salmonella typhimurium) | ||||||
| Activity: | Tryptophan synthase, with EC number 4.2.1.20 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
CRYSTAL STRUCTURE OF WILD-TYPE TRYPTOPHAN SYNTHASE COMPLEXED WITH INDOLE GLYCEROL PHOSPHATE
Overview
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 Structure
1QOQ is a Protein complex structure of sequences from Salmonella typhimurium. Full crystallographic information is available from OCA.
Reference
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
Page seeded by OCA on Sun Mar 23 13:22:23 2008
