5I3H

Structure-Function Studies on Role of Hydrophobic Clamping of a Basic Glutamate in Catalysis by Triosephosphate Isomerase


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.25 Å
  • R-Value Free: 0.211 
  • R-Value Work: 0.166 
  • R-Value Observed: 0.168 

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This is version 1.1 of the entry. See complete history


Literature

Structure-Function Studies of Hydrophobic Residues That Clamp a Basic Glutamate Side Chain during Catalysis by Triosephosphate Isomerase.

Richard, J.P.Amyes, T.L.Malabanan, M.M.Zhai, X.Kim, K.J.Reinhardt, C.J.Wierenga, R.K.Drake, E.J.Gulick, A.M.

(2016) Biochemistry 55: 3036-3047

  • DOI: 10.1021/acs.biochem.6b00311
  • Primary Citation of Related Structures:  
    5I3F, 5I3G, 5I3H, 5I3I, 5I3J, 5I3K

  • PubMed Abstract: 
  • Kinetic parameters are reported for the reactions of whole substrates (kcat/Km, M(-1) s(-1)) (R)-glyceraldehyde 3-phosphate (GAP) and dihydroxyacetone phosphate (DHAP) and for the substrate pieces [(kcat/Km)E·HPi/Kd, M(-2) s(-1)] glycolaldehyde (GA) and phosphite dianion (HPi) catalyzed by the I172A/L232A mutant of triosephosphate isomerase from Trypanosoma brucei brucei (TbbTIM) ...

    Kinetic parameters are reported for the reactions of whole substrates (kcat/Km, M(-1) s(-1)) (R)-glyceraldehyde 3-phosphate (GAP) and dihydroxyacetone phosphate (DHAP) and for the substrate pieces [(kcat/Km)E·HPi/Kd, M(-2) s(-1)] glycolaldehyde (GA) and phosphite dianion (HPi) catalyzed by the I172A/L232A mutant of triosephosphate isomerase from Trypanosoma brucei brucei (TbbTIM). A comparison with the corresponding parameters for wild-type, I172A, and L232A TbbTIM-catalyzed reactions shows that the effect of I172A and L232A mutations on ΔG(⧧) for the wild-type TbbTIM-catalyzed reactions of the substrate pieces is nearly the same as the effect of the same mutations on TbbTIM previously mutated at the second side chain. This provides strong evidence that mutation of the first hydrophobic side chain does not affect the functioning of the second side chain in catalysis of the reactions of the substrate pieces. By contrast, the effects of I172A and L232A mutations on ΔG(⧧) for wild-type TbbTIM-catalyzed reactions of the whole substrate are different from the effect of the same mutations on TbbTIM previously mutated at the second side chain. This is due to the change in the rate-determining step that determines the barrier to the isomerization reaction. X-ray crystal structures are reported for I172A, L232A, and I172A/L232A TIMs and for the complexes of these mutants to the intermediate analogue phosphoglycolate (PGA). The structures of the PGA complexes with wild-type and mutant enzymes are nearly superimposable, except that the space opened by replacement of the hydrophobic side chain is occupied by a water molecule that lies ∼3.5 Å from the basic side chain of Glu167. The new water at I172A mutant TbbTIM provides a simple rationalization for the increase in the activation barrier ΔG(⧧) observed for mutant enzyme-catalyzed reactions of the whole substrate and substrate pieces. By contrast, the new water at the L232A mutant does not predict the decrease in ΔG(⧧) observed for the mutant enzyme-catalyzed reactions of the substrate piece GA.


    Organizational Affiliation

    Department of Structural Biology, University at Buffalo, State University of New York , Buffalo, New York 14203, United States.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Triosephosphate isomerase, glycosomalA, B250Trypanosoma brucei bruceiMutation(s): 2 
EC: 5.3.1.1
UniProt
Find proteins for P04789 (Trypanosoma brucei brucei)
Explore P04789 
Go to UniProtKB:  P04789
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP04789
Protein Feature View
Expand
  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
PGA
Query on PGA

Download Ideal Coordinates CCD File 
E [auth B]2-PHOSPHOGLYCOLIC ACID
C2 H5 O6 P
ASCFNMCAHFUBCO-UHFFFAOYSA-N
 Ligand Interaction
K
Query on K

Download Ideal Coordinates CCD File 
C [auth A],
D [auth A]
POTASSIUM ION
K
NPYPAHLBTDXSSS-UHFFFAOYSA-N
 Ligand Interaction
Binding Affinity Annotations 
IDSourceBinding Affinity
PGA Binding MOAD:  5I3H Ki: 1.20e+5 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.25 Å
  • R-Value Free: 0.211 
  • R-Value Work: 0.166 
  • R-Value Observed: 0.168 
  • Space Group: P 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 46.282α = 72.68
b = 46.656β = 88.47
c = 60.981γ = 80.6
Software Package:
Software NamePurpose
PHENIXrefinement
d*TREKdata reduction
d*TREKdata scaling
MOLREPphasing

Structure Validation

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Ligand Structure Quality Assessment 



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2016-05-18
    Type: Initial release
  • Version 1.1: 2016-06-15
    Changes: Database references