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Title: Transport capabilities of environmental Pseudomonads for sulfur compounds

Abstract

Sulfur is an essential element in plant rhizospheres and microbial activity plays a key role in increasing the biological availability of sulfur in soil environments. To better understand the mechanisms facilitating the exchange of sulfur-containing molecules in soil, we profiled the binding specificities of eight previously uncharacterized ABC transporter solute-binding proteins from plant-associated Pseudomonads. A high-throughput screening procedure indicated eighteen significant organosulfur binding ligands, with at least one high-quality screening hit for each protein target. Calorimetric and spectroscopic methods were used to validate the best ligand assignments and catalog the thermodynamic properties of the protein-ligand interactions. Two novel high-affinity ligand binding activities were identified and quantified in this set of solute binding proteins. Bacteria were cultured in minimal media with screening library components supplied as the sole sulfur sources, demonstrating that these organosulfur compounds can be metabolized and confirming the relevance of ligand assignments. These results expand the set of experimentally validated ligands amenable to transport by this ABC transporter family and demonstrate the complex range of protein-ligand interactions that can be accomplished by solute-binding proteins. As a result, characterizing new nutrient import pathways provides insight into Pseudomonad metabolic capabilities which can be used to further interrogate bacterial survival andmore » participation in soil and rhizosphere communities.« less

Authors:
 [1];  [1];  [1];  [1]
  1. Argonne National Lab. (ANL), Lemont, IL (United States)
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
OSTI Identifier:
1371913
Alternate Identifier(s):
OSTI ID: 1401894
Grant/Contract Number:
AC02-06CH11357
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Protein Science
Additional Journal Information:
Journal Volume: 26; Journal Issue: 4; Journal ID: ISSN 0961-8368
Publisher:
The Protein Society
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; 60 APPLIED LIFE SCIENCES; ABC transporter; Pseudomonas fluorescens; Pseudomonas protegens; organosulfur compounds; rhizosphere

Citation Formats

Zerbs, Sarah, Korajczyk, Peter J., Noirot, Philippe H., and Collart, Frank R.. Transport capabilities of environmental Pseudomonads for sulfur compounds. United States: N. p., 2017. Web. doi:10.1002/pro.3124.
Zerbs, Sarah, Korajczyk, Peter J., Noirot, Philippe H., & Collart, Frank R.. Transport capabilities of environmental Pseudomonads for sulfur compounds. United States. doi:10.1002/pro.3124.
Zerbs, Sarah, Korajczyk, Peter J., Noirot, Philippe H., and Collart, Frank R.. Fri . "Transport capabilities of environmental Pseudomonads for sulfur compounds". United States. doi:10.1002/pro.3124. https://www.osti.gov/servlets/purl/1371913.
@article{osti_1371913,
title = {Transport capabilities of environmental Pseudomonads for sulfur compounds},
author = {Zerbs, Sarah and Korajczyk, Peter J. and Noirot, Philippe H. and Collart, Frank R.},
abstractNote = {Sulfur is an essential element in plant rhizospheres and microbial activity plays a key role in increasing the biological availability of sulfur in soil environments. To better understand the mechanisms facilitating the exchange of sulfur-containing molecules in soil, we profiled the binding specificities of eight previously uncharacterized ABC transporter solute-binding proteins from plant-associated Pseudomonads. A high-throughput screening procedure indicated eighteen significant organosulfur binding ligands, with at least one high-quality screening hit for each protein target. Calorimetric and spectroscopic methods were used to validate the best ligand assignments and catalog the thermodynamic properties of the protein-ligand interactions. Two novel high-affinity ligand binding activities were identified and quantified in this set of solute binding proteins. Bacteria were cultured in minimal media with screening library components supplied as the sole sulfur sources, demonstrating that these organosulfur compounds can be metabolized and confirming the relevance of ligand assignments. These results expand the set of experimentally validated ligands amenable to transport by this ABC transporter family and demonstrate the complex range of protein-ligand interactions that can be accomplished by solute-binding proteins. As a result, characterizing new nutrient import pathways provides insight into Pseudomonad metabolic capabilities which can be used to further interrogate bacterial survival and participation in soil and rhizosphere communities.},
doi = {10.1002/pro.3124},
journal = {Protein Science},
number = 4,
volume = 26,
place = {United States},
year = {Fri Jan 27 00:00:00 EST 2017},
month = {Fri Jan 27 00:00:00 EST 2017}
}

Journal Article:
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  • A global two-dimensional time-dependent model has been used to estimate the tropospheric distributions of sulfur compounds resulting from natural emissions of H/sub 2/S or DMS and from man-made emissions of SO/sub 2/. Comparisons of observations of H/sub 2/S, DMS, SO/sub 2/, and SO/sub 4//sup 2 -/ remote areas with the model estimates indicate that the global flux of H/sub 2/S and DMS, taken together, amounts to at most a few tens of tg s/yr. The present man-made emissions of SO/sub 2/ (about 80 tg s/yr) can account for a dominant part of the SO/sub 2/ and SO/sub 4//sup 2 -/more » observed in the lower troposphere of the northern hemisphere. On the other hand, neither natural emissions of H/sub 2/S and DMS at the surface nor man-made emissions of SO/sub 2/ seem to be able to explain the relatively high values of SO/sub 2/ observed in the middle and upper troposphere in both hemispheres. Our calculations indicate that a relatively long-lived precursor must be involved as a source for this SO/sub 2/. The amount of SO/sub 2/ produced by the oxidation of CS/sub 2/ and OCS does not seem sufficiently high. Average residence times in the atmosphere for H/sub 2/S, SO/sub 2/, and SO/sub 4//sup 2 -/ have been estimated to about 1, 1.5, and 5 days, respectively. If only higher portions of the troposphere are considered, the residence times increase considerably.« less
  • The stability of volatile organic compounds in environmental water samples has been studied, particularly with respect to the establishment of preanalytical holding times. Methods have been developed for the preparation of standard samples containing known concentrations of volatile organics. Three water samples were used: distilled water, surface water, and groundwater. Samples were stored at both room temperature and under refrigeration. Data were collected over a 365-day period by gas chromatography/mass spectrometry. In water samples containing low chloride content (distilled water), rapid dehydrohalogenation of tetrachloroethane to trichloroethylene occurred. Such degradation was also evident in the surface water and groundwater samples storedmore » at room temperature. A less rapid conversion of trichloroethane to dichloroethylene occurred in distilled water samples stored at 25{degree}C. Subsequently, experiments were conducted to determine the value of reduced pH in sample preservation. It was shown that acidification with hydrochloric acid effectively prevented degradation and allowed indefinite storage. However, sampling and analytical considerations make the use of HCl impractical. Therefore, a study was carried out using sodium bisulfate and ascorbic acid as preservatives. Both substances effectively preserved the samples, but sodium bisulfate proved to have several advantages over ascorbic acid. Samples preserved with either acid were stable over the 112-day experimental period.« less