Crystal structure of the K271E mutant of Mannonate dehydratase from Novosphingobium aromaticivorans complexed with Mg and D-mannonate

Experimental Data Snapshot

  • Resolution: 2.20 Å
  • R-Value Free: 0.206 
  • R-Value Work: 0.168 
  • R-Value Observed: 0.168 

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This is version 1.3 of the entry. See complete history


Evolution of enzymatic activities in the enolase superfamily: D-Mannonate dehydratase from Novosphingobium aromaticivorans.

Rakus, J.F.Fedorov, A.A.Fedorov, E.V.Glasner, M.E.Vick, J.E.Babbitt, P.C.Almo, S.C.Gerlt, J.A.

(2007) Biochemistry 46: 12896-12908

  • DOI: https://doi.org/10.1021/bi701703w
  • Primary Citation of Related Structures:  
    2QJJ, 2QJM, 2QJN

  • PubMed Abstract: 

    The d-mannonate dehydratase (ManD) function was assigned to a group of orthologous proteins in the mechanistically diverse enolase superfamily by screening a library of acid sugars. Structures of the wild type ManD from Novosphingobium aromaticivorans were determined at pH 7.5 in the presence of Mg2+ and also in the presence of Mg2+ and the 2-keto-3-keto-d-gluconate dehydration product; the structure of the catalytically active K271E mutant was determined at pH 5.5 in the presence of the d-mannonate substrate. As previously observed in the structures of other members of the enolase superfamily, ManD contains two domains, an N-terminal alpha+beta capping domain and a (beta/alpha)7beta-barrel domain. The barrel domain contains the ligands for the essential Mg2+, Asp 210, Glu 236, and Glu 262, at the ends of the third, fourth, and fifth beta-strands of the barrel domain, respectively. However, the barrel domain lacks both the Lys acid/base catalyst at the end of the second beta-strand and the His-Asp dyad acid/base catalyst at the ends of the seventh and sixth beta-strands, respectively, that are found in many members of the superfamily. Instead, a hydrogen-bonded dyad of Tyr 159 in a loop following the second beta-strand and Arg 147 at the end of the second beta-strand are positioned to initiate the reaction by abstraction of the 2-proton. Both Tyr 159 and His 212, at the end of the third beta-strand, are positioned to facilitate both syn-dehydration and ketonization of the resulting enol intermediate to yield the 2-keto-3-keto-d-gluconate product with the observed retention of configuration. The identities and locations of these acid/base catalysts as well as of cationic amino acid residues that stabilize the enolate anion intermediate define a new structural strategy for catalysis (subgroup) in the mechanistically diverse enolase superfamily. With these differences, we provide additional evidence that the ligands for the essential Mg2+ are the only conserved residues in the enolase superfamily, establishing the primary functional importance of the Mg2+-assisted strategy for stabilizing the enolate anion intermediate.

  • Organizational Affiliation

    Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Mandelate racemase/muconate lactonizing enzyme
A, B, C, D
402Novosphingobium aromaticivoransMutation(s): 1 
Find proteins for A4XF23 (Novosphingobium aromaticivorans (strain ATCC 700278 / DSM 12444 / CCUG 56034 / CIP 105152 / NBRC 16084 / F199))
Explore A4XF23 
Go to UniProtKB:  A4XF23
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupA4XF23
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.20 Å
  • R-Value Free: 0.206 
  • R-Value Work: 0.168 
  • R-Value Observed: 0.168 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 116.254α = 90
b = 165.312β = 90
c = 166.853γ = 90
Software Package:
Software NamePurpose
ADSCdata collection
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

View Full Validation Report

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2007-10-30
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Derived calculations, Version format compliance
  • Version 1.2: 2021-10-20
    Changes: Database references, Derived calculations
  • Version 1.3: 2023-08-30
    Changes: Data collection, Refinement description