Ligand binding domain (LBD) of the p. aeruginosa histamine receptor TlpQ

Experimental Data Snapshot

  • Resolution: 2.45 Å
  • R-Value Free: 0.237 
  • R-Value Work: 0.193 

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High-Affinity Chemotaxis to Histamine Mediated by the TlpQ Chemoreceptor of the Human Pathogen Pseudomonas aeruginosa.

Corral-Lugo, A.Matilla, M.A.Martin-Mora, D.Silva Jimenez, H.Mesa Torres, N.Kato, J.Hida, A.Oku, S.Conejero-Muriel, M.Gavira, J.A.Krell, T.

(2018) mBio 9

  • DOI: https://doi.org/10.1128/mBio.01894-18
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Histamine is a key biological signaling molecule. It acts as a neurotransmitter in the central and peripheral nervous systems and coordinates local inflammatory responses by modulating the activity of different immune cells. During inflammatory processes, including bacterial infections, neutrophils stimulate the production and release of histamine. Here, we report that the opportunistic human pathogen Pseudomonas aeruginosa exhibits chemotaxis toward histamine. This chemotactic response is mediated by the concerted action of the TlpQ, PctA, and PctC chemoreceptors, which display differing sensitivities to histamine. Low concentrations of histamine were sufficient to activate TlpQ, which binds histamine with an affinity of 639 nM. To explore this binding, we resolved the high-resolution structure of the TlpQ ligand binding domain in complex with histamine. It has an unusually large dCACHE domain and binds histamine through a highly negatively charged pocket at its membrane distal module. Chemotaxis to histamine may play a role in the virulence of P. aeruginosa by recruiting cells at the infection site and consequently modulating the expression of quorum-sensing-dependent virulence genes. TlpQ is the first bacterial histamine receptor to be described and greatly differs from human histamine receptors, indicating that eukaryotes and bacteria have pursued different strategies for histamine recognition. IMPORTANCE Genome analyses indicate that many bacteria possess an elevated number of chemoreceptors, suggesting that these species are able to perform chemotaxis to a wide variety of compounds. The scientific community is now only beginning to explore this diversity and to elucidate the corresponding physiological relevance. The discovery of histamine chemotaxis in the human pathogen Pseudomonas aeruginosa provides insight into tactic movements that occur within the host. Since histamine is released in response to bacterial pathogens, histamine chemotaxis may permit bacterial migration and accumulation at infection sites, potentially modulating, in turn, quorum-sensing-mediated processes and the expression of virulence genes. As a consequence, the modulation of histamine chemotaxis by signal analogues may result in alterations of the bacterial virulence. As the first report of bacterial histamine chemotaxis, this study lays the foundation for the exploration of the physiological relevance of histamine chemotaxis and its role in pathogenicity.

  • Organizational Affiliation

    Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Probable chemotaxis transducer
A, B, C, D
345Pseudomonas aeruginosa PAO1Mutation(s): 0 
Gene Names: PA2654
Find proteins for Q9I0I4 (Pseudomonas aeruginosa (strain ATCC 15692 / DSM 22644 / CIP 104116 / JCM 14847 / LMG 12228 / 1C / PRS 101 / PAO1))
Explore Q9I0I4 
Go to UniProtKB:  Q9I0I4
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9I0I4
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 4 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
HSM (Subject of Investigation/LOI)
Query on HSM

Download Ideal Coordinates CCD File 
E [auth A],
H [auth B],
J [auth C],
N [auth D]
C5 H9 N3
Query on PO4

Download Ideal Coordinates CCD File 
F [auth A],
K [auth C]
O4 P
Query on GOL

Download Ideal Coordinates CCD File 
G [auth A],
I [auth B],
L [auth C],
O [auth D]
C3 H8 O3
Query on ACT

Download Ideal Coordinates CCD File 
C2 H3 O2
Modified Residues  1 Unique
IDChains TypeFormula2D DiagramParent
Query on MSE
A, B, C, D
Binding Affinity Annotations 
IDSourceBinding Affinity
HSM Binding MOAD:  6FU4 Kd: 639 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Resolution: 2.45 Å
  • R-Value Free: 0.237 
  • R-Value Work: 0.193 
  • Space Group: P 21 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 81.616α = 90
b = 103.983β = 90
c = 147.452γ = 90
Software Package:
Software NamePurpose
XDSdata reduction
Aimlessdata scaling

Structure Validation

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Ligand Structure Quality Assessment 

Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number

Revision History  (Full details and data files)

  • Version 1.0: 2018-05-16
    Type: Initial release
  • Version 1.1: 2018-11-21
    Changes: Data collection, Database references
  • Version 1.2: 2018-11-28
    Changes: Data collection, Database references