Metabolic Value Chemoattractants Are Preferentially Recognized at Broad Ligand Range Chemoreceptor of Pseudomonas putida KT2440
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 tha...
Main Authors: | , , , |
---|---|
Format: | Article |
Language: | English |
Published: |
Frontiers Media S.A.
2017-05-01
|
Series: | Frontiers in Microbiology |
Subjects: | |
Online Access: | http://journal.frontiersin.org/article/10.3389/fmicb.2017.00990/full |
id |
doaj-20f7dd39864542bea1b3f87fd1cadbc6 |
---|---|
record_format |
Article |
spelling |
doaj-20f7dd39864542bea1b3f87fd1cadbc62020-11-24T23:57:24ZengFrontiers Media S.A.Frontiers in Microbiology1664-302X2017-05-01810.3389/fmicb.2017.00990272340Metabolic Value Chemoattractants Are Preferentially Recognized at Broad Ligand Range Chemoreceptor of Pseudomonas putida KT2440Matilde FernándezMiguel A. MatillaÁlvaro OrtegaTino KrellBacteria 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.http://journal.frontiersin.org/article/10.3389/fmicb.2017.00990/fullchemotaxischemoreceptorligand recognitionisothermal titration calorimetryPseudomonas |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Matilde Fernández Miguel A. Matilla Álvaro Ortega Tino Krell |
spellingShingle |
Matilde Fernández Miguel A. Matilla Álvaro Ortega Tino Krell Metabolic Value Chemoattractants Are Preferentially Recognized at Broad Ligand Range Chemoreceptor of Pseudomonas putida KT2440 Frontiers in Microbiology chemotaxis chemoreceptor ligand recognition isothermal titration calorimetry Pseudomonas |
author_facet |
Matilde Fernández Miguel A. Matilla Álvaro Ortega Tino Krell |
author_sort |
Matilde Fernández |
title |
Metabolic Value Chemoattractants Are Preferentially Recognized at Broad Ligand Range Chemoreceptor of Pseudomonas putida KT2440 |
title_short |
Metabolic Value Chemoattractants Are Preferentially Recognized at Broad Ligand Range Chemoreceptor of Pseudomonas putida KT2440 |
title_full |
Metabolic Value Chemoattractants Are Preferentially Recognized at Broad Ligand Range Chemoreceptor of Pseudomonas putida KT2440 |
title_fullStr |
Metabolic Value Chemoattractants Are Preferentially Recognized at Broad Ligand Range Chemoreceptor of Pseudomonas putida KT2440 |
title_full_unstemmed |
Metabolic Value Chemoattractants Are Preferentially Recognized at Broad Ligand Range Chemoreceptor of Pseudomonas putida KT2440 |
title_sort |
metabolic value chemoattractants are preferentially recognized at broad ligand range chemoreceptor of pseudomonas putida kt2440 |
publisher |
Frontiers Media S.A. |
series |
Frontiers in Microbiology |
issn |
1664-302X |
publishDate |
2017-05-01 |
description |
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. |
topic |
chemotaxis chemoreceptor ligand recognition isothermal titration calorimetry Pseudomonas |
url |
http://journal.frontiersin.org/article/10.3389/fmicb.2017.00990/full |
work_keys_str_mv |
AT matildefernandez metabolicvaluechemoattractantsarepreferentiallyrecognizedatbroadligandrangechemoreceptorofpseudomonasputidakt2440 AT miguelamatilla metabolicvaluechemoattractantsarepreferentiallyrecognizedatbroadligandrangechemoreceptorofpseudomonasputidakt2440 AT alvaroortega metabolicvaluechemoattractantsarepreferentiallyrecognizedatbroadligandrangechemoreceptorofpseudomonasputidakt2440 AT tinokrell metabolicvaluechemoattractantsarepreferentiallyrecognizedatbroadligandrangechemoreceptorofpseudomonasputidakt2440 |
_version_ |
1725454193349623808 |