Crystal Structure of R314A N-acetyl Neuraminic Acid Synthase from Neiserria meningitidis with Malate bound

Experimental Data Snapshot

  • Resolution: 1.75 Å
  • R-Value Free: 0.197 
  • R-Value Work: 0.161 
  • R-Value Observed: 0.165 

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This is version 1.2 of the entry. See complete history


Arg314 Is Essential for Catalysis by N-Acetyl Neuraminic Acid Synthase from Neisseria meningitidis.

Joseph, D.D.Jiao, W.Parker, E.J.

(2013) Biochemistry 52: 2609-2619

  • DOI: https://doi.org/10.1021/bi400062c
  • Primary Citation of Related Structures:  
    4IPI, 4IPJ

  • PubMed Abstract: 

    The sialic acid N-acetylneuraminic acid (NANA) has a key role in the pathogenesis of a select number of neuroinvasive bacteria such as Neisseria meningitidis. These pathogens coat themselves with polysialic acids, mimicking the exterior surface of mammalian cells and consequentially concealing the bacteria from the host's immune system. NANA is synthesized in bacteria by the homodimeric enzyme NANA synthase (NANAS), which catalyzes a condensation reaction between phosphoenolpyruvate (PEP) and N-acetylmannosamine (ManNAc). NANAS is closely related to the α-keto acid synthases 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase and 3-deoxy-d-manno-octulosonate 8-phosphate synthase. NANAS differs from these enzymes in that it contains an antifreeze protein like (AFPL) domain, which extends from the C-terminal of the (β/α)8 barrel containing the active site and contributes a highly conserved arginine (Arg314) into the active site of the opposing monomer chain. We have investigated the role of Arg314 in NmeNANAS through mutagenesis and a combination of kinetic and structural analyses. Using isothermal titration calorimetry and molecular modeling, we have shown that Arg314 is required for the catalytic function of NANAS and that the delocalized positively charged guanidinium functionality of this residue provides steering of the sugar substrate ManNAc for suitable placement in the active site and thus reaction with PEP.

  • 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
Polysialic acid capsule biosynthesis protein SiaC351Neisseria meningitidisMutation(s): 1 
Gene Names: siaCNMB0068
Find proteins for Q57265 (Neisseria meningitidis)
Explore Q57265 
Go to UniProtKB:  Q57265
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ57265
Sequence Annotations
  • Reference Sequence
Small Molecules
Binding Affinity Annotations 
IDSourceBinding Affinity
LMR PDBBind:  4IPI Kd: 4800 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Resolution: 1.75 Å
  • R-Value Free: 0.197 
  • R-Value Work: 0.161 
  • R-Value Observed: 0.165 
  • Space Group: P 21 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 58α = 90
b = 75.8β = 90
c = 77.52γ = 90
Software Package:
Software NamePurpose
Blu-Icedata collection
CCP4model building
iMOSFLMdata reduction
SCALAdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2013-04-10
    Type: Initial release
  • Version 1.1: 2013-05-01
    Changes: Database references
  • Version 1.2: 2023-09-20
    Changes: Data collection, Database references, Derived calculations, Refinement description