4EJ0

Crystal structure of ADP-L-glycero-D-manno-heptose-6-epimerase from Burkholderia thailandensis


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.61 Å
  • R-Value Free: 0.241 
  • R-Value Work: 0.185 
  • R-Value Observed: 0.188 

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Literature

Structure and in silico substrate-binding mode of ADP-L-glycero-D-manno-heptose 6-epimerase from Burkholderia thailandensis.

Kim, M.S.Lim, A.Yang, S.W.Park, J.Lee, D.Shin, D.H.

(2013) Acta Crystallogr D Biol Crystallogr 69: 658-668

  • DOI: 10.1107/S0907444913001030
  • Primary Citation of Related Structures:  
    4EJ0

  • PubMed Abstract: 
  • ADP-L-glycero-D-manno-heptose 6-epimerase (AGME), the product of the rfaD gene, is the last enzyme in the heptose-biosynthesis pathway; it converts ADP-D-glycero-D-manno-heptose (ADP-D,D-Hep) to ADP-L-glycero-D-manno-heptose (ADP-L,D-Hep). AGME contains a catalytic triad involved in catalyzing hydride transfer with the aid of NADP(+) ...

    ADP-L-glycero-D-manno-heptose 6-epimerase (AGME), the product of the rfaD gene, is the last enzyme in the heptose-biosynthesis pathway; it converts ADP-D-glycero-D-manno-heptose (ADP-D,D-Hep) to ADP-L-glycero-D-manno-heptose (ADP-L,D-Hep). AGME contains a catalytic triad involved in catalyzing hydride transfer with the aid of NADP(+). Defective lipopolysaccharide is found in bacterial mutants lacking this gene. Therefore, it is an interesting target enzyme for a novel epimerase inhibitor for use as a co-therapy with antibiotics. The crystal structure of AGME from Burkholderia thailandensis (BtAGME), a surrogate organism for studying the pathogenicity of melioidosis caused by B. pseudomallei, has been determined. The crystal structure determined with co-purified NADP(+) revealed common as well as unique structural properties of the AGME family when compared with UDP-galactose 4-epimerase homologues. They form a similar architecture with conserved catalytic residues. Nevertheless, there are differences in the substrate- and cofactor-binding cavities and the oligomerization domains. Structural comparison of BtAGME with AGME from Escherichia coli indicates that they may recognize their substrate in a `lock-and-key' fashion. Unique structural features of BtAGME are found in two regions. The first region is the loop between β8 and β9, affecting the binding affinity of BtAGME for the ADP moiety of ADP-D,D-Hep. The second region is helix α8, which induces decamerization at low pH that is not found in other AGMEs. With the E210G mutant, it was observed that the resistance of the wild type to acid-induced denaturation is related to the decameric state. An in silico study was performed using the Surflex-Dock GeomX module of the SYBYL-X 1.3 software to predict the catalytic mechanism of BtAGME with its substrate, ADP-D,D-Hep. In the in silico study, the C7'' hydroxymethyl group of ADP-D,D-Hep is predicted to form hydrogen bonds to Ser116 and Gln293. With the aid of these interactions, the hydroxyl of Tyr139 forms a hydrogen bond to O6″ of ADP-D,D-Hep and the proton at C6″ orients closely to C4 of NADP(+). Therefore, the in silico study supports a one-base mechanism as a major catalytic pathway, in which Tyr139 solely functions as a catalytic acid/base residue. These results provide a new insight into the development of an epimerase inhibitor as an antibiotic adjuvant against melioidosis.


    Organizational Affiliation

    The Center for Cell Signaling and Drug Discovery Research, College of Pharmacy, Division of Life and Pharmaceutical Sciences, Ewha Womans University, Seoul, Republic of Korea.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
ADP-L-glycero-D-manno-heptose-6-epimerase
A, B, C, D, E, F, G, H, I, J
A, B, C, D, E, F, G, H, I, J
342Burkholderia thailandensis E264Mutation(s): 0 
Gene Names: hldDBTH_I1644
EC: 5.1.3.20
UniProt
Find proteins for Q2SY18 (Burkholderia thailandensis (strain ATCC 700388 / DSM 13276 / CIP 106301 / E264))
Explore Q2SY18 
Go to UniProtKB:  Q2SY18
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ2SY18
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.61 Å
  • R-Value Free: 0.241 
  • R-Value Work: 0.185 
  • R-Value Observed: 0.188 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 158.317α = 90
b = 160.923β = 90
c = 169.628γ = 90
Software Package:
Software NamePurpose
ADSCdata collection
EPMRphasing
PHENIXrefinement
MOSFLMdata reduction
SCALAdata scaling

Structure Validation

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Entry History 

Deposition Data

  • Deposited Date: 2012-04-06 
  • Released Date: 2013-04-17 
  • Deposition Author(s): Kim, M.S., Shin, D.H.

Revision History  (Full details and data files)

  • Version 1.0: 2013-04-17
    Type: Initial release