Conserved hydrophilic checkpoints tune FocA-mediated formate:H<sup>+</sup> symport.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41145500.
- Also identified by DOI 10.1038/s41467-025-65159-3 and PMC identifier 12559229.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
FocA belongs to the widespread, evolutionarily ancient formate-nitrite transporter (FNT) family of pentameric anion channels and translocates formic acid bidirectionally. Here, we identify compartmentalized polarity distribution across the complete FocA pore structure - resolved at 2.56 Å - mirrored against a two-fold axis with H209 at its center. A FocA-H209N variant that exhibits an efflux-only channel-like function in vivo reveals a density consistent with formate located directly at N209, abolishing the channel's amphiphilicity. Pyruvate formate-lyase, which generates formate, orients at the cytoplasmic face where formate delivery is regulated by conformational changes in the FocA vestibule. Comparisons with other FNTs suggest a tuning mechanism of formate-specific transport via checkpoints enriched in hydrophilic residues.
Medical subject headings
- Formates
- Escherichia coli Proteins
- Membrane Transport Proteins
- Escherichia coli
- Symporters