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Volume 168, Issue 4

The FocA channel functions to maintain intracellular formate homeostasis during fermentation Open Access

Abstract

FocA translocates formate/formic acid bi-directionally across the cytoplasmic membrane when grows by fermentation. It remains unclear, however, what physiological benefit is imparted by FocA, because formic acid (p =3.75) can diffuse passively across the membrane, especially at low pH. Here, we monitored changes in intra- and extracellular formate levels during batch-culture fermentation, comparing a parental K-12 strain with its isogenic mutant. Our results show that, regardless of the initial pH in the culture, FocA functions to maintain relatively constant intracellular formate levels during growth. Analysis of a strain synthesizing a FocA variant with an exchange in a conserved threonine residue within the translocation pore revealed the strain accumulated formate intracellularly and imported formate poorly, but in a pH-dependent manner, which was different to uptake by native FocA. We conclude that FocA maintains formate homeostasis, using different mechanisms for efflux and uptake of the anion.

  • Received:
  • Accepted:
  • Published Online:
Keyword(s): Anion channel , FNT family , FocA pore , formate translocation and threonine-91
© 2022 The Authors
  • This is an open-access article distributed under the terms of the Creative Commons Attribution License.
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2022-04-04
2024-04-24
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References

  1. Knappe J, Sawers G. A radical-chemical route to acetyl-CoA: the anaerobically induced pyruvate formate-lyase system of Escherichia coli. FEMS Microbiol Rev 1990; 6:383–398 [View Article] [PubMed]
     [Google Scholar]
  2. Suppmann B, Sawers G. Isolation and characterization of hypophosphite--resistant mutants of Escherichia coli: identification of the FocA protein, encoded by the pfl operon, as a putative formate transporter. Mol Microbiol 1994; 11:965–982 [View Article] [PubMed]
     [Google Scholar]
  3. Sawers RG. Formate and its role in hydrogen production in Escherichia coli . Biochem Soc Trans 2005; 33:42–46 [View Article] [PubMed]
     [Google Scholar]
  4. Wang Y, Huang Y, Wang J, Cheng C, Huang W et al. Structure of the formate transporter FocA reveals a pentameric aquaporin-like channel. Nature 2009; 462:467–472 [View Article] [PubMed]
     [Google Scholar]
  5. Czyzewski BK, Wang D-N. Identification and characterization of a bacterial hydrosulphide ion channel. Nature 2012; 483:494–497 [View Article] [PubMed]
     [Google Scholar]
  6. Wu B, Rambow J, Bock S, Holm-Bertelsen J, Wiechert M et al. Identity of a Plasmodium lactate/H(+) symporter structurally unrelated to human transporters. Nat Commun 2015; 6:6284 [View Article] [PubMed]
     [Google Scholar]
  7. Lü W, Schwarzer NJ, Du J, Gerbig-Smentek E, Andrade SLA et al. Structural and functional characterization of the nitrite channel NirC from Salmonella typhimurium . Proc Natl Acad Sci U S A 2012; 109:18395–18400 [View Article] [PubMed]
     [Google Scholar]
  8. Mukherjee M, Vajpai M, Sankararamakrishnan R. Anion-selective Formate/nitrite transporters: taxonomic distribution, phylogenetic analysis and subfamily-specific conservation pattern in prokaryotes. BMC Genomics 2017; 18:560 [View Article] [PubMed]
     [Google Scholar]
  9. Rossmann R, Sawers G, Böck A. Mechanism of regulation of the formate-hydrogenlyase pathway by oxygen, nitrate, and pH: definition of the formate regulon. Mol Microbiol 1991; 5:2807–2814 [View Article] [PubMed]
     [Google Scholar]
  10. Hopper S, Böck A. Effector-mediated stimulation of ATPase activity by the sigma 54-dependent transcriptional activator FHLA from Escherichia coli . J Bacteriol 1995; 177:2798–2803 [View Article] [PubMed]
     [Google Scholar]
  11. Sargent F. The Model [NiFe]-Hydrogenases of Escherichia coli . Adv Microb Physiol 2016; 68:433–507 [View Article] [PubMed]
     [Google Scholar]
  12. Pinske C, Sawers RG. Anaerobic formate and hydrogen metabolism. EcoSal Plus 2016; 7: [View Article] [PubMed]
     [Google Scholar]
  13. Doberenz C, Zorn M, Falke D, Nannemann D, Hunger D et al. Pyruvate formate-lyase interacts directly with the formate channel FocA to regulate formate translocation. J Mol Biol 2014; 426:2827–2839 [View Article] [PubMed]
     [Google Scholar]
  14. Kammel M, Hunger D, Sawers RG. The soluble cytoplasmic N-terminal domain of the FocA channel gates bidirectional formate translocation. Mol Microbiol 2021; 115:758–773 [View Article] [PubMed]
     [Google Scholar]
  15. Hunger D, Doberenz C, Sawers RG. Identification of key residues in the formate channel FocA that control import and export of formate. Biol Chem 2014; 395:813–825 [View Article] [PubMed]
     [Google Scholar]
  16. Kammel M, Trebbin O, Pinske C, Sawers RG. A single amino acid exchange converts FocA into A unidirectional efflux channel for formate. Microbiology (Reading) 2022; 168:001132 [View Article] [PubMed]
     [Google Scholar]
  17. Waight AB, Love J, Wang D-N. Structure and mechanism of a pentameric formate channel. Nat Struct Mol Biol 2010; 17:31–37 [View Article] [PubMed]
     [Google Scholar]
  18. Lü W, Du J, Wacker T, Gerbig-Smentek E, Andrade SLA et al. pH-dependent gating in a FocA formate channel. Science 2011; 332:352–354 [View Article] [PubMed]
     [Google Scholar]
  19. Beyer L, Doberenz C, Falke D, Hunger D, Suppmann B et al. Coordination of FocA and pyruvate formate-lyase synthesis in Escherichia coli demonstrates preferential translocation of formate over other mixed-acid fermentation products. J Bacteriol 2013; 195:1428–1435 [View Article] [PubMed]
     [Google Scholar]
  20. Theobald DL, Miller C. Membrane transport proteins: surprises in structural sameness. Nat Struct Mol Biol 2010; 17:2–3 [View Article] [PubMed]
     [Google Scholar]
  21. Casadaban MJ. Transposition and fusion of the lac genes to selected promoters in Escherichia coli using bacteriophage lambda and Mu. J Mol Biol 1976; 104:541–555 [View Article] [PubMed]
     [Google Scholar]
  22. Hamilton CM, Aldea M, Washburn BK, Babitzke P, Kushner SR. New method for generating deletions and gene replacements in Escherichia coli . J Bacteriol 1989; 171:4617–4622 [View Article] [PubMed]
     [Google Scholar]
  23. Miller J. Experiments in Molecular Genetics Cold Spring Harbor, NY: Cold Spring Harbor Laboratory; 1972
     [Google Scholar]
  24. Lü W, Du J, Schwarzer NJ, Wacker T, Andrade SLA et al. The formate/nitrite transporter family of anion channels. Biol Chem 2013; 394:715–727 [View Article] [PubMed]
     [Google Scholar]
  25. Atkovska K, Hub JS. Energetics and mechanism of anion permeation across formate-nitrite transporters. Sci Rep 2017; 7:12027 [View Article] [PubMed]
     [Google Scholar]
  26. Pravda L, Sehnal D, Toušek D, Navrátilová V, Bazgier V et al. MOLEonline: a web-based tool for analyzing channels, tunnels and pores (2018 update). Nucleic Acids Res 2018; 46:W368–W373 [View Article] [PubMed]
     [Google Scholar]
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The FocA channel functions to maintain intracellular formate homeostasis during Escherichia coli fermentation
Microbiology 168, 001168 (2022); https://doi.org/10.1099/mic.0.001168
/content/journal/micro/10.1099/mic.0.001168
/content/journal/micro/10.1099/mic.0.001168
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