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Phosphite binding by the HtxB periplasmic binding protein depends on the protonation state of the ligand

Adams, Nathan B.P. ; Robertson, Angus J. LU ; Hunter, C. Neil ; Hitchcock, Andrew and Bisson, Claudine (2019) In Scientific Reports 9(1).
Abstract
Phosphorus acquisition is critical for life. In low phosphate conditions, some species of bacteria have evolved mechanisms to import reduced phosphorus compounds, such as phosphite and hypophosphite, as alternative phosphorus sources. Uptake is facilitated by high-affinity periplasmic binding proteins (PBPs) that bind cargo in the periplasm and shuttle it to an ATP-binding cassette (ABC)-transporter in the bacterial inner membrane. PtxB and HtxB are the PBPs responsible for binding phosphite and hypophosphite, respectively. They recognize the P-H bond of phosphite/hypophosphite via a conserved P-H...π interaction, which confers nanomolar dissociation constants for their respective ligands. PtxB also has a low-level binding affinity for... (More)
Phosphorus acquisition is critical for life. In low phosphate conditions, some species of bacteria have evolved mechanisms to import reduced phosphorus compounds, such as phosphite and hypophosphite, as alternative phosphorus sources. Uptake is facilitated by high-affinity periplasmic binding proteins (PBPs) that bind cargo in the periplasm and shuttle it to an ATP-binding cassette (ABC)-transporter in the bacterial inner membrane. PtxB and HtxB are the PBPs responsible for binding phosphite and hypophosphite, respectively. They recognize the P-H bond of phosphite/hypophosphite via a conserved P-H...π interaction, which confers nanomolar dissociation constants for their respective ligands. PtxB also has a low-level binding affinity for phosphate and hypophosphite, whilst HtxB can facilitate phosphite uptake in vivo. However, HtxB does not bind phosphate, thus the HtxBCDE transporter has recently been successfully exploited for biocontainment of genetically modified organisms by phosphite-dependent growth. Here we use a combination of X-ray crystallography, NMR and Microscale Thermophoresis to show that phosphite binding to HtxB depends on the protonation state of the ligand, suggesting that pH may effect the efficiency of phosphite uptake by HtxB in biotechnology applications. (Less)
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author
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publishing date
type
Contribution to journal
publication status
published
in
Scientific Reports
volume
9
issue
1
article number
10231
publisher
Nature Publishing Group
external identifiers
  • scopus:85069517586
ISSN
2045-2322
DOI
10.1038/s41598-019-46557-2
language
English
LU publication?
no
id
59225153-4e44-441a-aea3-5a03f713253e
date added to LUP
2024-01-25 13:45:20
date last changed
2024-01-29 09:10:02
@article{59225153-4e44-441a-aea3-5a03f713253e,
  abstract     = {{Phosphorus acquisition is critical for life. In low phosphate conditions, some species of bacteria have evolved mechanisms to import reduced phosphorus compounds, such as phosphite and hypophosphite, as alternative phosphorus sources. Uptake is facilitated by high-affinity periplasmic binding proteins (PBPs) that bind cargo in the periplasm and shuttle it to an ATP-binding cassette (ABC)-transporter in the bacterial inner membrane. PtxB and HtxB are the PBPs responsible for binding phosphite and hypophosphite, respectively. They recognize the P-H bond of phosphite/hypophosphite via a conserved P-H...π interaction, which confers nanomolar dissociation constants for their respective ligands. PtxB also has a low-level binding affinity for phosphate and hypophosphite, whilst HtxB can facilitate phosphite uptake in vivo. However, HtxB does not bind phosphate, thus the HtxBCDE transporter has recently been successfully exploited for biocontainment of genetically modified organisms by phosphite-dependent growth. Here we use a combination of X-ray crystallography, NMR and Microscale Thermophoresis to show that phosphite binding to HtxB depends on the protonation state of the ligand, suggesting that pH may effect the efficiency of phosphite uptake by HtxB in biotechnology applications.}},
  author       = {{Adams, Nathan B.P. and Robertson, Angus J. and Hunter, C. Neil and Hitchcock, Andrew and Bisson, Claudine}},
  issn         = {{2045-2322}},
  language     = {{eng}},
  month        = {{07}},
  number       = {{1}},
  publisher    = {{Nature Publishing Group}},
  series       = {{Scientific Reports}},
  title        = {{Phosphite binding by the HtxB periplasmic binding protein depends on the protonation state of the ligand}},
  url          = {{http://dx.doi.org/10.1038/s41598-019-46557-2}},
  doi          = {{10.1038/s41598-019-46557-2}},
  volume       = {{9}},
  year         = {{2019}},
}