Crystal structure of citrate synthase (Msed_0281) from Metallosphaera sedula in complex with acetyl-CoA

Experimental Data Snapshot

  • Resolution: 1.72 Å
  • R-Value Free: 0.196 
  • R-Value Work: 0.150 
  • R-Value Observed: 0.152 

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Crystal structure and biochemical properties of msed_0281, the citrate synthase from Metallosphaera sedula.

Lee, S.H.Kim, K.J.

(2019) Biochem Biophys Res Commun 509: 722-727

  • DOI: https://doi.org/10.1016/j.bbrc.2018.12.172
  • Primary Citation of Related Structures:  
    6ABV, 6ABW

  • PubMed Abstract: 

    Metallosphaera sedula is a thermoacidophilic archaeon that has carbon fixation ability using the 3-hydroxypropionate/4-hydroxybutyrate(3-HP/4-HB) cycle, and has an incomplete TCA cycle to produce necessary biosynthetic precursors. The citrate synthase from M. sedula (MsCS) is an enzyme involved in the first step of the incomplete TCA cycle, catalyzing the conversion of oxaloacetate and acetyl-CoA into citrate and coenzyme A. To investigate the molecular mechanism of MsCS, we determined its crystal structure at 1.8 Å resolution. As other known CSs, MsCS functions as a dimer, and each monomer consists of two domains, a large domain and a small domain. We also determined the structure of the complex with acetyl-CoA and revealed the acetyl-CoA binding mode of MsCS. Structural comparison of MsCS with another CS in complex with oxaloacetate enabled us to predict the oxaloacetate binding site. Moreover, we performed inhibitory kinetic analyses of MsCS, and showed that the protein is inhibited by citrate and ATP by competitive and non-competitive inhibition modes, respectively, but not by NADH. Based on these results, we suggest that MsCS belongs to the type-I CS with structural and biochemical properties similar to those of CSs involved in the conventional TCA cycle.

  • Organizational Affiliation

    School of Life Sciences (KNU Creative BioResearch Group), KNU Institute for Microorganisms, Kyungpook National University, Daegu, 41566, Republic of Korea. Electronic address: kkim@knu.ac.kr.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Citrate synthase390Metallosphaera sedula DSM 5348Mutation(s): 0 
Gene Names: Msed_0281
Find proteins for A4YDF6 (Metallosphaera sedula (strain ATCC 51363 / DSM 5348 / JCM 9185 / NBRC 15509 / TH2))
Explore A4YDF6 
Go to UniProtKB:  A4YDF6
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupA4YDF6
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.72 Å
  • R-Value Free: 0.196 
  • R-Value Work: 0.150 
  • R-Value Observed: 0.152 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 61.609α = 90
b = 94.806β = 90
c = 129.863γ = 90
Software Package:
Software NamePurpose
HKL-2000data reduction
PDB_EXTRACTdata extraction
HKL-2000data scaling

Structure Validation

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Ligand Structure Quality Assessment 

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2019-01-16
    Type: Initial release
  • Version 1.1: 2019-01-30
    Changes: Data collection, Database references
  • Version 1.2: 2023-11-22
    Changes: Data collection, Database references, Refinement description