Crystal structure of A58P, DEL(N59), and loop 7 truncated mutant of 3-deoxy-D-manno-octulosonate 8-phosphate synthase (KDO8PS) from Neisseria meningitidis

Experimental Data Snapshot

  • Resolution: 2.20 Å
  • R-Value Free: 0.238 
  • R-Value Work: 0.197 
  • R-Value Observed: 0.199 

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An Extended (beta)7(alpha)7 Substrate-Binding Loop Is Essential for Efficient Catalysis by 3-Deoxy-D-manno-Octulosonate 8-Phosphate Synthase

Allison, T.M.Hutton, R.D.Jiao, W.Gloyne, B.J.Nimmo, E.B.Jameson, G.B.Parker, E.J.

(2011) Biochemistry 50: 9318-9327

  • DOI: https://doi.org/10.1021/bi201231e
  • Primary Citation of Related Structures:  
    3STC, 3STE, 3STF, 3STG

  • PubMed Abstract: 

    The enzyme 3-deoxy-D-manno-octulosonate 8-phosphate (KDO8P) synthase catalyzes the reaction between phosphoenolpyruvate and arabinose 5-phosphate (A5P) in the first committed step in the biosynthetic pathway for the formation of 3-deoxy-D-manno-octulosonate, an important component in the cell wall of Gram-negative bacteria. KDO8P synthase is evolutionarily related to the first enzyme of the shikimate pathway, 3-deoxy-D-arabino-heptulosonate 7-phosphate (DAH7P) synthase, which uses erythrose 4-phosphate in place of A5P. The A5P binding site in KDO8P synthase is formed by three long loops that extend from the core catalytic (β/α)(8) barrel, β2α2, β7α7, and β8α8. The extended β7α7 loop is always present in KDO8P synthase yet is not observed for DAH7P synthase. Modeling of this loop indicated interactions between this loop and the extended β2α2 loop; both loops provide key hydrogen-bonding contacts with A5P. The two absolutely conserved residues on the β7α7 loop (Gln and Ser) were mutated to Ala in both the metal-dependent KDO8P synthase from Acidithiobacillus ferrooxidans and the metal-independent KDO8P synthase from Neisseria meningitidis. In addition, mutants were constructed for both enzymes with the extended β7α7 loop excised to match the DAH7P synthase architecture. Removal of the loop extension severely hindered efficient catalysis, dramatically increasing the K(m)(A5P) and reducing the k(cat) for both enzymes. Excision of the complete loop was far more detrimental to catalysis than the double mutations of the two conserved Gln and Ser residues. Therefore, the presence of the entire extended β7α7 loop is important for efficient catalysis by KDO8P synthase, with the loop acting to promote efficient and productive binding of A5P.

  • Organizational Affiliation

    Biomolecular Interaction Centre and Department of Chemistry, University of Canterbury, Christchurch, New Zealand.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
2-dehydro-3-deoxyphosphooctonate aldolase
A, B, C, D
268Neisseria meningitidis MC58Mutation(s): 1 
Gene Names: kdsANMB1283
Find proteins for Q9JZ55 (Neisseria meningitidis serogroup B (strain MC58))
Explore Q9JZ55 
Go to UniProtKB:  Q9JZ55
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9JZ55
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on CL

Download Ideal Coordinates CCD File 
E [auth A]
F [auth A]
G [auth A]
H [auth B]
I [auth B]
E [auth A],
F [auth A],
G [auth A],
H [auth B],
I [auth B],
J [auth B],
K [auth B],
L [auth C],
M [auth C],
N [auth D],
O [auth D],
P [auth D]
Experimental Data & Validation

Experimental Data

  • Resolution: 2.20 Å
  • R-Value Free: 0.238 
  • R-Value Work: 0.197 
  • R-Value Observed: 0.199 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 81.69α = 90
b = 104.05β = 90
c = 149.62γ = 90
Software Package:
Software NamePurpose
MOSFLMdata reduction
SCALAdata scaling
PDB_EXTRACTdata extraction
ADSCdata collection

Structure Validation

View Full Validation Report

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2011-11-23
    Type: Initial release
  • Version 1.1: 2023-11-01
    Changes: Data collection, Database references, Derived calculations, Refinement description