Structural Basis for Polyamine Binding at the dCACHE Domain of the McpU Chemoreceptor from Pseudomonas putida

Gavira, José A.; Ortega, Álvaro; Martín‐Mora, David; Conejero-Muriel, Mayte; Corral-Lugo, Andrés; Morel, Bertrand; Matilla, Miguel A.; Krell, Tino

doi:10.1016/j.jmb.2018.05.008

Cited by 36 publications

(36 citation statements)

References 59 publications

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“…Although CAD2 shows a fold similar to that of CAD1, the ligands bind only to CAD1 ( Fig. 2B to G), like other known dCACHE-type chemoreceptors except for TlpC (10)(11)(12)(13).…”

Section: Resultsmentioning

confidence: 84%

Calcium Ions Modulate Amino Acid Sensing of the Chemoreceptor Mlp24 of Vibrio cholerae

et al. 2019

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Bacteria sense environmental chemicals using chemosensor proteins, most of which are present in the cytoplasmic membrane. Canonical chemoreceptors bind their specific ligands in their periplasmic domain, and the ligand binding creates a molecular stimulus that is transmitted into the cytoplasm, leading to various cellular responses, such as chemotaxis and specific gene expression. Vibrio cholerae, the causative agent of cholera, contains about 44 putative sensor proteins, which are homologous to methyl-accepting chemotaxis proteins involved in chemotaxis. Two of them, Mlp24 and Mlp37, have been identified as chemoreceptors that mediate chemotactic responses to various amino acids. Although most of the residues of Mlp37 involved in ligand binding are conserved in Mlp24, these chemoreceptors bind the same ligands with different affinities. Moreover, they have distinct cellular roles. Here we determined a series of ligand complex structures of the periplasmic domains of Mlp24 (Mlp24p). The structures revealed that Ca 2ϩ binds to the loop that forms the upper wall of the ligand-binding pocket. Ca 2ϩ does not bind to the corresponding loop of Mlp37, implying that the structural difference of the loop may cause the ligand affinity difference. Isothermal titration calorimetry (ITC) measurements indicated that Ca 2ϩ changes the ligand binding affinity of Mlp24p. Furthermore, Ca 2ϩ affected chemotactic behaviors to various amino acids mediated by Mlp24. Thus, Ca 2ϩ is suggested to serve as a cosignal for the primary signal mediated by Mlp24p, and V. cholerae fine-tunes its chemotactic behavior depending on the Ca 2ϩ concentration by modulating the ligand sensitivity of Mlp24. IMPORTANCE Mlp24 and Mlp37 are homologous chemoreceptors of Vibrio cholerae that bind various amino acids. Although most of the residues involved in ligand interaction are conserved, these chemoreceptors show different affinities for the same ligand and play different cellular roles. A series of ligand complex structures of the periplasmic region of Mlp24 (Mlp24p) and following ITC analysis revealed that Ca 2ϩ binds to the loop of Mlp24p and modulates the ligand binding affinity of Mlp24p. Moreover, Ca 2ϩ changes the chemotactic behaviors mediated by Mlp24. We propose that Ca 2ϩ acts as a cosignal that modulates the affinity of Mlp24 for the primary signal, thereby changing the chemotactic behavior of V. cholerae.

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“…Although CAD2 shows a fold similar to that of CAD1, the ligands bind only to CAD1 ( Fig. 2B to G), like other known dCACHE-type chemoreceptors except for TlpC (10)(11)(12)(13).…”

Section: Resultsmentioning

confidence: 84%

Calcium Ions Modulate Amino Acid Sensing of the Chemoreceptor Mlp24 of Vibrio cholerae

et al. 2019

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“…Among the functionally annotated KT2440 chemotaxis receptors are several for different organic acids ( 18 ), purines ( 19 ), proteinogenic amino acids ( 20 ), and gamma-aminobutyric acid (GABA) ( 21 ). In addition, the McpU chemoreceptor of this strain was the first chemoreceptor identified that responded to the polyamines putrescine, spermidine, and cadaverine ( 20 , 22 ). In contrast, PAO1 chemotaxis to proteinogenic amino acids and GABA is mediated by three paralogous receptors, namely, PctA, PctB, and PctC ( 23 , 24 ).…”

Section: Introductionmentioning

confidence: 99%

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

Corral-Lugo

Matilla

Martín‐Mora

et al. 2018

mBio

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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.

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“…Similar to Tar, some other helical LBDs also alter the oligomeric state upon ligand binding, such as 4HB domains of PcaY_PP (Fernandez et al , ) and CtpH (Rico‐Jimenez et al , ), HBM domains of McpS (Lacal et al , ) and McpQ (Martin‐Mora et al , ), and PilJ domain of McpN (Martin‐Mora et al , ). On the contrary, the oligomerization of some dCACHE and sCACHE LBDs is not altered by ligand binding and their ligand binding sites are not located at the dimeric interface (Rico‐Jimenez et al , ; Martin‐Mora et al , ; Gavira et al , ). For example, the dCACHE of the P. aeruginosa PctA chemoreceptor was found as a monomer in both ligand‐free and ligand‐bound states (Rico‐Jimenez et al , ), and the sCACHE domain of P. aeruginosa PA2652 chemoreceptor exists as dimer in both states (Martin‐Mora et al , ).…”

Section: Introductionmentioning

confidence: 99%

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

Yuan

Huang

Guo

et al. 2019

Molecular Microbiology

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Summary 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.

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Structural Basis for Polyamine Binding at the dCACHE Domain of the McpU Chemoreceptor from Pseudomonas putida

Cited by 36 publications

References 59 publications

Calcium Ions Modulate Amino Acid Sensing of the Chemoreceptor Mlp24 of Vibrio cholerae

Calcium Ions Modulate Amino Acid Sensing of the Chemoreceptor Mlp24 of Vibrio cholerae

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

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

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