2CLK

Tryptophan Synthase in complex with D-glyceraldehyde 3-phosphate (G3P)


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.50 Å
  • R-Value Free: 0.202 
  • R-Value Work: 0.179 
  • R-Value Observed: 0.180 

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Ligand Structure Quality Assessment 


This is version 1.2 of the entry. See complete history


Literature

Synthesis and Characterization of Allosteric Probes of Substrate Channeling in the Tryptophan Synthase Bienzyme Complex.

Ngo, H.Harris, R.Kimmich, N.Casino, P.Niks, D.Blumenstein, L.Barends, T.R.Kulik, V.Weyand, M.Schlichting, I.Dunn, M.F.

(2007) Biochemistry 46: 7713

  • DOI: https://doi.org/10.1021/bi700385f
  • Primary Citation of Related Structures:  
    2CLE, 2CLF, 2CLH, 2CLI, 2CLK

  • PubMed Abstract: 

    Allosteric interactions regulate substrate channeling in Salmonella typhimurium tryptophan synthase. The channeling of indole between the alpha- and beta-sites via the interconnecting 25 A tunnel is regulated by allosteric signaling arising from binding of ligand to the alpha-site, and covalent reaction of l-Ser at the beta-site. This signaling switches the alpha- and beta-subunits between open conformations of low activity and closed conformations of high activity. Our objective is to synthesize and characterize new classes of alpha-site ligands (ASLs) that mimic the binding of substrates, 3-indole-d-glycerol 3'-phosphate (IGP) or d-glyceraldehyde 3-phosphate (G3P), for use in the investigation of alpha-site-beta-site interactions. The new synthesized IGP analogues contain an aryl group linked to an O-phosphoethanolamine moiety through amide, sulfonamide, or thiourea groups. The G3P analogue, thiophosphoglycolohydroxamate, contains a hydroxamic acid group linked to a thiophosphate moiety. Crystal structures of the internal aldimine complexed with G3P and with three of the new ASLs are presented. These structural and solution studies of the ASL complexes with the internal aldimine form of the enzyme establish the following. (1) ASL binding occurs with high specificity and relatively high affinities at the alpha-site. (2) Binding of the new ASLs slows the entry of indole analogues into the beta-site by blocking the tunnel opening at the alpha-site. (3) ASL binding stabilizes the closed conformations of the beta-subunit for the alpha-aminoacrylate and quinonoid forms of the enzyme. (4) The new ASLs exhibit allosteric properties that parallel the behaviors of IGP and G3P.


  • Organizational Affiliation

    Department of Biochemistry, University of California, Riverside, California 92521, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
TRYPTOPHAN SYNTHASE ALPHA CHAIN268Salmonella enterica subsp. enterica serovar TyphimuriumMutation(s): 0 
EC: 4.2.1.20
UniProt
Find proteins for P00929 (Salmonella typhimurium (strain LT2 / SGSC1412 / ATCC 700720))
Explore P00929 
Go to UniProtKB:  P00929
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP00929
Sequence Annotations
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  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
TRYPTOPHAN SYNTHASE BETA CHAIN396Salmonella enterica subsp. enterica serovar TyphimuriumMutation(s): 0 
EC: 4.2.1.20
UniProt
Find proteins for P0A2K1 (Salmonella typhimurium (strain LT2 / SGSC1412 / ATCC 700720))
Explore P0A2K1 
Go to UniProtKB:  P0A2K1
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP0A2K1
Sequence Annotations
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  • Reference Sequence
Small Molecules
Binding Affinity Annotations 
IDSourceBinding Affinity
G3H PDBBind:  2CLK Kd: 1.64e+5 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.50 Å
  • R-Value Free: 0.202 
  • R-Value Work: 0.179 
  • R-Value Observed: 0.180 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 182.045α = 90
b = 59.558β = 94.56
c = 67.409γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
XDSdata reduction
XSCALEdata scaling

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2007-06-12
    Type: Initial release
  • Version 1.1: 2011-05-08
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance