Details
| Original language | English |
|---|---|
| Pages (from-to) | 560-568 |
| Number of pages | 9 |
| Journal | Applied and Environmental Microbiology |
| Volume | 65 |
| Issue number | 2 |
| Publication status | Published - 1 Feb 1999 |
| Externally published | Yes |
Abstract
We report here that the naturally occurring choline ester choline-O- sulfate serves as an effective compatible solute for Bacillus subtilis, and we have identified a high-affinity ATP-binding cassette (ABC) transport system responsible for its uptake. The osmoprotective effect of this trimethylammonium compound closely matches that of the potent and widely employed osmoprotectant glycine betaine. Growth experiments with a set of B. subtilis strains carrying defined mutations in the glycine betaine uptake systems OpuA, OpuC, and OpuD and in the high-affinity choline transporter OpuB revealed that choline-O-sulfate was specifically acquired from the environment via OpuC. Competition experiments demonstrated that choline-O- sulfate functioned as an effective competitive inhibitor for OpuC-mediated glycine betaine uptake, with a K(i) of approximately 4 μM. Uptake studies with [1,2-ditnethyl-14C]choline-O-sulfate showed that its transport was stimulated by high osmolality, and kinetic analysis revealed that OpuC has high affinity for choline-O-sulfate, with a K(m) value of 4 ± 1 μM and a maximum rate of transport (V(max)) of 54 ± 3 nmol/min · mg of protein in cells grown in minimal medium with 0.4 M NaCl. Growth studies utilizing a B. subtilis mutant defective in the choline to glycine betaine synthesis pathway and natural abundance 13C nuclear magnetic resonance spectroscopy of whole- cell extracts from the wild-type strain demonstrated that choline-O-sulfate was accumulated in the cytoplasm and was not hydrolyzed to choline by B. subtilis. In contrast, the osmoprotective effect of acetylcholine for B. subtilis is dependent on its biotransformation into glycine betaine. Choline- O-sulfate was not used as the sole carbon, nitrogen, or sulfur source, and our findings thus characterize this choline ester as an effective compatible solute and metabolically inert stress compound for B. subtilis. OpuC mediates the efficient transport not only of glycine betaine and choline-O-sulfate but also of carnitine, crotonobetaine, and γ-butyrobetaine (R. Kappes and E. Bremer, Microbiology 144:83-90, 1998). Thus, our data underscore its crucial role in the acquisition of a variety of osmoprotectants from the environment by B. subtilis.
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)
- Biotechnology
- Agricultural and Biological Sciences(all)
- Food Science
- Immunology and Microbiology(all)
- Applied Microbiology and Biotechnology
- Environmental Science(all)
- Ecology
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In: Applied and Environmental Microbiology, Vol. 65, No. 2, 01.02.1999, p. 560-568.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - High-affinity transport of choline-O-sulfate and its use as a compatible solute in Bacillus subtilis
AU - Nau-Wagner, Gabriele
AU - Boch, Jens
AU - Le Good, J. Ann
AU - Bremer, Erhard
N1 - Copyright: Copyright 2020 Elsevier B.V., All rights reserved.
PY - 1999/2/1
Y1 - 1999/2/1
N2 - We report here that the naturally occurring choline ester choline-O- sulfate serves as an effective compatible solute for Bacillus subtilis, and we have identified a high-affinity ATP-binding cassette (ABC) transport system responsible for its uptake. The osmoprotective effect of this trimethylammonium compound closely matches that of the potent and widely employed osmoprotectant glycine betaine. Growth experiments with a set of B. subtilis strains carrying defined mutations in the glycine betaine uptake systems OpuA, OpuC, and OpuD and in the high-affinity choline transporter OpuB revealed that choline-O-sulfate was specifically acquired from the environment via OpuC. Competition experiments demonstrated that choline-O- sulfate functioned as an effective competitive inhibitor for OpuC-mediated glycine betaine uptake, with a K(i) of approximately 4 μM. Uptake studies with [1,2-ditnethyl-14C]choline-O-sulfate showed that its transport was stimulated by high osmolality, and kinetic analysis revealed that OpuC has high affinity for choline-O-sulfate, with a K(m) value of 4 ± 1 μM and a maximum rate of transport (V(max)) of 54 ± 3 nmol/min · mg of protein in cells grown in minimal medium with 0.4 M NaCl. Growth studies utilizing a B. subtilis mutant defective in the choline to glycine betaine synthesis pathway and natural abundance 13C nuclear magnetic resonance spectroscopy of whole- cell extracts from the wild-type strain demonstrated that choline-O-sulfate was accumulated in the cytoplasm and was not hydrolyzed to choline by B. subtilis. In contrast, the osmoprotective effect of acetylcholine for B. subtilis is dependent on its biotransformation into glycine betaine. Choline- O-sulfate was not used as the sole carbon, nitrogen, or sulfur source, and our findings thus characterize this choline ester as an effective compatible solute and metabolically inert stress compound for B. subtilis. OpuC mediates the efficient transport not only of glycine betaine and choline-O-sulfate but also of carnitine, crotonobetaine, and γ-butyrobetaine (R. Kappes and E. Bremer, Microbiology 144:83-90, 1998). Thus, our data underscore its crucial role in the acquisition of a variety of osmoprotectants from the environment by B. subtilis.
AB - We report here that the naturally occurring choline ester choline-O- sulfate serves as an effective compatible solute for Bacillus subtilis, and we have identified a high-affinity ATP-binding cassette (ABC) transport system responsible for its uptake. The osmoprotective effect of this trimethylammonium compound closely matches that of the potent and widely employed osmoprotectant glycine betaine. Growth experiments with a set of B. subtilis strains carrying defined mutations in the glycine betaine uptake systems OpuA, OpuC, and OpuD and in the high-affinity choline transporter OpuB revealed that choline-O-sulfate was specifically acquired from the environment via OpuC. Competition experiments demonstrated that choline-O- sulfate functioned as an effective competitive inhibitor for OpuC-mediated glycine betaine uptake, with a K(i) of approximately 4 μM. Uptake studies with [1,2-ditnethyl-14C]choline-O-sulfate showed that its transport was stimulated by high osmolality, and kinetic analysis revealed that OpuC has high affinity for choline-O-sulfate, with a K(m) value of 4 ± 1 μM and a maximum rate of transport (V(max)) of 54 ± 3 nmol/min · mg of protein in cells grown in minimal medium with 0.4 M NaCl. Growth studies utilizing a B. subtilis mutant defective in the choline to glycine betaine synthesis pathway and natural abundance 13C nuclear magnetic resonance spectroscopy of whole- cell extracts from the wild-type strain demonstrated that choline-O-sulfate was accumulated in the cytoplasm and was not hydrolyzed to choline by B. subtilis. In contrast, the osmoprotective effect of acetylcholine for B. subtilis is dependent on its biotransformation into glycine betaine. Choline- O-sulfate was not used as the sole carbon, nitrogen, or sulfur source, and our findings thus characterize this choline ester as an effective compatible solute and metabolically inert stress compound for B. subtilis. OpuC mediates the efficient transport not only of glycine betaine and choline-O-sulfate but also of carnitine, crotonobetaine, and γ-butyrobetaine (R. Kappes and E. Bremer, Microbiology 144:83-90, 1998). Thus, our data underscore its crucial role in the acquisition of a variety of osmoprotectants from the environment by B. subtilis.
UR - http://www.scopus.com/inward/record.url?scp=0033013656&partnerID=8YFLogxK
U2 - 10.1128/aem.65.2.560-568.1999
DO - 10.1128/aem.65.2.560-568.1999
M3 - Article
AN - SCOPUS:0033013656
VL - 65
SP - 560
EP - 568
JO - Applied and Environmental Microbiology
JF - Applied and Environmental Microbiology
SN - 0099-2240
IS - 2
ER -