Direct sensing and signal transduction during bacterial chemotaxis toward aromatic compounds in <i>Comamonas testosteroni</i>

Huang, Zhou; Ni, Bin; Jiang, Ching-Long; Wu, Yu; He, Yunlong; Parales, Rebecca E.; Liu, Shuang Jiang

doi:10.1111/mmi.13385

Cited by 34 publications

(29 citation statements)

References 67 publications

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“…All of these compounds support the growth of the bacterium (Ni et al, 2013b) and further studies showed that the chemoreceptors MCP2201, MCP2901, and MCP2983 mediate taxis to these compounds (Ni et al, 2013a, 2015; Huang et al, 2016). These receptors possess a four-helix bundle LBD but employ different mechanisms.…”

Section: Discussionmentioning

confidence: 99%

“…This hypothesis was supported by the fact that the observed chemotaxis was metabolism dependent (Ni et al, 2013a). In marked contrast, the mechanism of MCP2901 is based on the direct binding of aromatic acids to the periplasmic LBD (Huang et al, 2016); although affinities were relatively weak ( K D values typically of several hundreds of μM) and thus inferior to the corresponding values of PcaY_PP. Taken together, there are thus two fundamentally different mechanism of chemotaxis to aromatic acids.…”

Section: Discussionmentioning

confidence: 99%

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Metabolic Value Chemoattractants Are Preferentially Recognized at Broad Ligand Range Chemoreceptor of Pseudomonas putida KT2440

et al. 2017

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Bacteria have evolved a wide range of chemoreceptors with different ligand specificities. Typically, chemoreceptors bind ligands with elevated specificity and ligands serve as growth substrates. However, there is a chemoreceptor family that has a broad ligand specificity including many compounds that are not of metabolic value. To advance the understanding of this family, we have used the PcaY_PP (PP2643) chemoreceptor of Pseudomonas putida KT2440 as a model. Using Isothermal Titration Calorimetry we showed here that the recombinant ligand binding domain (LBD) of PcaY_PP recognizes 17 different C6-ring containing carboxylic acids with KD values between 3.7 and 138 μM and chemoeffector affinity correlated with the magnitude of the chemotactic response. Mutation of the pcaY_PP gene abolished chemotaxis to these compounds; phenotype that was restored following gene complementation. Growth experiments using PcaY_PP ligands as sole C-sources revealed functional relationships between their metabolic potential and affinity for the chemoreceptor. Thus, only 7 PcaY_PP ligands supported growth and their KD values correlated with the length of the bacterial lag phase. Furthermore, PcaY_PP ligands that did not support growth had significantly higher KD values than those that did. The receptor has thus binds preferentially compounds that serve as C-sources and amongst them those that rapidly promote growth. Tightest binding compounds were quinate, shikimate, 3-dehydroshikimate and protocatechuate, which are at the interception of the biosynthetic shikimate and catabolic quinate pathways. Analytical ultracentrifugation studies showed that ligand free PcaY_PP-LBD is present in a monomer-dimer equilibrium (KD = 57.5 μM). Ligand binding caused a complete shift to the dimeric state, which appears to be a general feature of four-helix bundle LBDs. This study indicates that the metabolic potential of compounds is an important parameter in the molecular recognition by broad ligand range chemoreceptors.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Metabolic Value Chemoattractants Are Preferentially Recognized at Broad Ligand Range Chemoreceptor of Pseudomonas putida KT2440

et al. 2017

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“…The MCP2201 gene, as well as its upstream 150 bp DNA that contains a native promoter, has been inserted into the plasmid pBBR1MCS-2 for chemotaxis assays. This plasmid has been used in the study of another C. testosteroni chemoreceptor MCP2901 (Huang et al, 2016) and its copy number is 6 per cell in C. testosteroni (Xiong and Maser, 2001). Swimming plate assays were performed as previously described (Huang et al, 2016).…”

Section: Strains Cultural Conditions and Chemotaxis Assaysmentioning

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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“…Halogenated aromatic compounds are found in many industrial commodities such as pesticides, flame-retardants, hydraulic fluids, and synthetic intermediates for pharmaceutical agents [2–4]. Several strategies are being explored to remove these toxic compounds from the environment.…”

Section: Introductionmentioning

confidence: 99%

“…Several strategies are being explored to remove these toxic compounds from the environment. One particularly attractive strategy is bioremediation, which uses microbial catabolic pathways to process the toxic species to metabolic intermediates that frequently can be channeled to the Krebs Cycle [2–5]. This approach requires a thorough understanding of each of the pathway steps.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and enzymatic ketonization of the 5-(halo)-2-hydroxymuconates and 5-(halo)-2-hydroxy-2,4-pentadienoates

Stack¹,

Johnson²,

Whitman³

2017

Beilstein J. Org. Chem.

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5-Halo-2-hydroxymuconates and 5-halo-2-hydroxy-2,4-pentadienoates are stable dienols that are proposed intermediates in bacterial meta-fission pathways for the degradation of halogenated aromatic compounds. The presence of the halogen raises questions about how the bulk and/or electronegativity of these substrates would affect enzyme catalysis or whether some pathway enzymes have evolved to accommodate it. To address these questions, 5-halo-2-hydroxymuconates and 5-halo-2-hydroxy-2,4-pentadienoates (5-halo = Cl, Br, F) were synthesized and a preliminary analysis of their enzymatic properties carried out. In aqueous buffer, 5-halo-2-hydroxy-2,4-pentadienoates rapidly equilibrate with the β,γ-unsaturated ketones. For the 5-chloro and 5-bromo derivatives, a slower conversion to the α,β-isomers follows. There is no detectable formation of the α,β-isomer for the 5-fluoro derivative. Kinetic parameters were also obtained for both sets of compounds in the presence of 4-oxalocrotonate tautomerase (4-OT) from Pseudomonas putida mt-2 and Leptothrix cholodnii SP-6. For 5-halo-2-hydroxymuconates, there are no major differences in the kinetic parameters for the two enzymes (following the formation of the β,γ-unsaturated ketones). In contrast, the L. cholodnii SP-6 4-OT is ≈10-fold less efficient than the P. putida mt-2 4-OT in the formation of the β,γ-unsaturated ketones and the α,β-isomers from the 5-halo-2-hydroxy-2,4-pentadienoates. The implications of these findings are discussed. The availability of these compounds will facilitate future studies of the haloaromatic catabolic pathways.

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Direct sensing and signal transduction during bacterial chemotaxis toward aromatic compounds in Comamonas testosteroni

Cited by 34 publications

References 67 publications

Metabolic Value Chemoattractants Are Preferentially Recognized at Broad Ligand Range Chemoreceptor of Pseudomonas putida KT2440

Metabolic Value Chemoattractants Are Preferentially Recognized at Broad Ligand Range Chemoreceptor of Pseudomonas putida KT2440

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

Synthesis and enzymatic ketonization of the 5-(halo)-2-hydroxymuconates and 5-(halo)-2-hydroxy-2,4-pentadienoates

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