3DFT

Phosphate ions in D33S mutant fructose-1,6-bisphosphate aldolase from rabbit muscle


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.94 Å
  • R-Value Free: 0.205 
  • R-Value Work: 0.149 

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This is version 1.2 of the entry. See complete history


Literature

Charge stabilization and entropy reduction of central lysine residues in fructose-bisphosphate aldolase

St-Jean, M.Blonski, C.Sygusch, J.

(2009) Biochemistry 48: 4528-4537

  • DOI: 10.1021/bi8021558
  • Primary Citation of Related Structures:  
    3DFN, 3DFO, 3DFP, 3DFQ, 3DFS, 3DFT

  • PubMed Abstract: 
  • Fructose-1,6-bisphosphate muscle aldolase is an essential glycolytic enzyme that catalyzes reversible carbon-carbon bond formation by cleaving fructose 1,6-bisphosphate to yield dihydroxyacetone phosphate (DHAP) and d-glyceraldehyde phosphate. To elucidate the mechanistic role of conserved amino acid Asp-33, Asn-33 and Ser-33 mutants were examined by kinetic and structural analyses ...

    Fructose-1,6-bisphosphate muscle aldolase is an essential glycolytic enzyme that catalyzes reversible carbon-carbon bond formation by cleaving fructose 1,6-bisphosphate to yield dihydroxyacetone phosphate (DHAP) and d-glyceraldehyde phosphate. To elucidate the mechanistic role of conserved amino acid Asp-33, Asn-33 and Ser-33 mutants were examined by kinetic and structural analyses. The mutations significantly compromised enzymatic activity and carbanion oxidation in presence of DHAP. Detailed structural analysis demonstrated that, like native crystals, Asp-33 mutant crystals, soaked in DHAP solutions, trapped Schiff base-derived intermediates covalently attached to Lys-229. The mutant structures, however, exhibited an abridged conformational change with the helical region (34-65) flanking the active site as well as pK(a) reductions and increased side chain disorder by central lysine residues, Lys-107 and Lys-146. These changes directly affect their interaction with the C-terminal Tyr-363, consistent with the absence of active site binding by the C-terminal region in the presence of phosphate. Lys-146 pK(a) reduction and side chain disorder would further compromise charge stabilization during C-C bond cleavage and proton transfer during enamine formation. These mechanistic impediments explain diminished catalytic activity and a reduced level of carbanion oxidation and are consistent with rate-determining proton transfer observed in the Asn-33 mutant. Asp-33 reduces the entropic cost and augments the enthalpic gain during catalysis by rigidifying Lys-107 and Lys-146, stabilizing their protonated forms, and promoting a conformational change triggered by substrate or obligate product binding, which lower kinetic barriers in C-C bond cleavage and Schiff base-enamine interconversion.


    Organizational Affiliation

    Déepartement de Biochimie, Université de Montréal, Québec H3C 3J7, Canada.



Macromolecules
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Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Fructose-bisphosphate aldolase AA, B, C, D363Oryctolagus cuniculusMutation(s): 1 
Gene Names: ALDOA
EC: 4.1.2.13
UniProt
Find proteins for P00883 (Oryctolagus cuniculus)
Explore P00883 
Go to UniProtKB:  P00883
Protein Feature View
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  • Reference Sequence
Small Molecules
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.94 Å
  • R-Value Free: 0.205 
  • R-Value Work: 0.149 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 83.926α = 90
b = 103.615β = 98.72
c = 84.946γ = 90
Software Package:
Software NamePurpose
CBASSdata collection
CNSrefinement
HKL-2000data reduction
HKL-2000data scaling
CNSphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2009-04-28
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2021-10-20
    Changes: Database references, Derived calculations