Ternary complex of ObcA with C4-CoA adduct and oxalate

Experimental Data Snapshot

  • Resolution: 2.28 Å
  • R-Value Free: 0.235 
  • R-Value Work: 0.202 
  • R-Value Observed: 0.204 

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Structural Basis for Bacterial Quorum Sensing-mediated Oxalogenesis.

Oh, J.Goo, E.Hwang, I.Rhee, S.

(2014) J Biol Chem 289: 11465-11475

  • DOI: https://doi.org/10.1074/jbc.M113.543462
  • Primary Citation of Related Structures:  
    4NNA, 4NNB, 4NNC

  • PubMed Abstract: 

    The Burkholderia species utilize acetyl-CoA and oxaloacetate, substrates for citrate synthase in the TCA cycle, to produce oxalic acid in response to bacterial cell to cell communication, called quorum sensing. Quorum sensing-mediated oxalogenesis via a sequential reaction by ObcA and ObcB counteracts the population-collapsing alkaline pH of the stationary growth phase. Thus, the oxalic acid produced plays an essential role as an excreted public good for survival of the group. Here, we report structural and functional analyses of ObcA, revealing mechanistic features distinct from those of citrate synthase. ObcA exhibits a unique fold, in which a (β/α)8-barrel fold is located in the C-domain with the N-domain inserted into a loop following α1 in the barrel fold. Structural analyses of the complexes with oxaloacetate and with a bisubstrate adduct indicate that each of the oxaloacetate and acetyl-CoA substrates is bound to an independent site near the metal coordination shell in the barrel fold. In catalysis, oxaloacetate serves as a nucleophile by forming an enolate intermediate mediated by Tyr(322) as a general base, which then attacks the thioester carbonyl carbon of acetyl-CoA to yield a tetrahedral adduct between the two substrates. Therefore, ObcA catalyzes its reaction by combining the enolase and acetyltransferase superfamilies, but the presence of the metal coordination shell and the absence of general acid(s) produces an unusual tetrahedral CoA adduct as a stable product. These results provide the structural basis for understanding the first step in oxalogenesis and constitute an example of the functional diversity of an enzyme for survival and adaptation in the environment.

  • Organizational Affiliation

    Department of Agricultural Biotechnology and Seoul National University, Seoul 151-921, Korea; Center for Fungal Pathogenesis, Seoul National University, Seoul 151-921, Korea. Electronic address: srheesnu@snu.ac.kr.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
OBCA, Oxalate Biosynthetic Component A542Burkholderia glumae BGR1Mutation(s): 0 
Gene Names: bglu_2g18790
EC: 4.1.3
Find proteins for C5AJX5 (Burkholderia glumae (strain BGR1))
Explore C5AJX5 
Go to UniProtKB:  C5AJX5
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupC5AJX5
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 3 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on 2KQ

Download Ideal Coordinates CCD File 
D [auth A] (3S)-3-[2-[3-[[(2R)-4-[[[(2R,3S,4R,5R)-5-(6-aminopurin-9-yl)-4-oxidanyl-3-phosphonooxy-oxolan-2-yl]methoxy-oxidanyl-phosphoryl]oxy-oxidanyl-phosphoryl]oxy-3,3-dimethyl-2-oxidanyl-butanoyl]amino]propanoylamino]ethylsulfanyl]-3-oxidanyl-butanoic acid
C25 H42 N7 O19 P3 S
Query on OXL

Download Ideal Coordinates CCD File 
C2 O4
Query on CO

Download Ideal Coordinates CCD File 
Experimental Data & Validation

Experimental Data

  • Resolution: 2.28 Å
  • R-Value Free: 0.235 
  • R-Value Work: 0.202 
  • R-Value Observed: 0.204 
  • Space Group: P 43 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 174.634α = 90
b = 174.634β = 90
c = 46.057γ = 90
Software Package:
Software NamePurpose
HKL-2000data collection
PHENIXmodel building
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2014-03-19
    Type: Initial release
  • Version 1.1: 2014-04-23
    Changes: Database references
  • Version 1.2: 2014-05-07
    Changes: Database references
  • Version 1.3: 2023-09-20
    Changes: Data collection, Database references, Derived calculations, Refinement description