The ligand-free dimer of chemoreceptor MCP2201 ligand binding domain

Experimental Data Snapshot

  • Resolution: 2.80 Å
  • R-Value Free: 0.266 
  • R-Value Work: 0.222 
  • R-Value Observed: 0.224 

Starting Model: experimental
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This is version 1.2 of the entry. See complete history


The ligand-binding domain of a chemoreceptor from Comamonas testosteroni has a previously unknown homotrimeric structure.

Hong, Y.Huang, Z.Guo, L.Ni, B.Jiang, C.Y.Li, X.J.Hou, Y.J.Yang, W.S.Wang, D.C.Zhulin, I.B.Liu, S.J.Li, D.F.

(2019) Mol Microbiol 

  • DOI: https://doi.org/10.1111/mmi.14326
  • Primary Citation of Related Structures:  
    5XUA, 5XUB, 6ITS

  • PubMed Abstract: 

    Transmembrane chemoreceptors are widely present in Bacteria and Archaea. They play a critical role in sensing various signals outside and transmitting to the cell interior. Here, we report the structure of the periplasmic ligand-binding domain (LBD) of the transmembrane chemoreceptor MCP2201, which governs chemotaxis to citrate and other organic compounds in Comamonas testosteroni. The apo-form LBD crystal revealed a typical four-helix bundle homodimer, similar to previously well-studied chemoreceptors such as Tar and Tsr of Escherichia coli. However, the citrate-bound LBD revealed a four-helix bundle homotrimer that had not been observed in bacterial chemoreceptor LBDs. This homotrimer was further confirmed with size-exclusion chromatography, analytical ultracentrifugation and cross-linking experiments. The physiological importance of the homotrimer for chemotaxis was demonstrated with site-directed mutations of key amino acid residues in C. testosteroni mutants.

  • Organizational Affiliation

    State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, No. 1 Beichen West Road, Chaoyang District, Beijing, 100101, China.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Methyl-accepting chemotaxis sensory transducer
A, B, C, D, E
A, B, C, D, E, F, G, H
154Comamonas testosteroni CNB-2Mutation(s): 0 
Gene Names: CtCNB1_2201
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.80 Å
  • R-Value Free: 0.266 
  • R-Value Work: 0.222 
  • R-Value Observed: 0.224 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 64.78α = 90
b = 105.03β = 90.95
c = 91.07γ = 90
Software Package:
Software NamePurpose
iMOSFLMdata processing
SCALAdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2018-06-27
    Type: Initial release
  • Version 1.1: 2019-07-10
    Changes: Data collection, Database references
  • Version 1.2: 2023-11-22
    Changes: Data collection, Database references, Refinement description