Structural insights into fosfomycin efflux by a streptococcal ABC transporter.

Authors

Atsushi Taguchi, Junso Fujita, Mikio Tanabe, Daisuke Takaya, Kazuo Harada, Toshio Moriya, Kaori Fukuzawa, Keiichi Namba, Kunihiko Nishino

Published in

Proceedings of the National Academy of Sciences of the United States of America. Volume 123. Issue 35. Pages e2535933123. Epub Aug 28, 2026.

Abstract

Gram-positive bacteria encode a broad array of ABC transporters that mediate substrate translocation across the cell membrane, with some contributing to their survival under environmental stresses such as antimicrobial exposure. While several of these transporters have been shown to exhibit multidrug efflux activity, the functional roles of many others remain unknown. Here, using an efflux pump screen in the opportunistic human pathogen Streptococcus pneumoniae, we identified a previously uncharacterized type IV ABC transporter (FoeAB) that confers resistance to the antibiotic fosfomycin. We show that purified FoeAB mediates fosfomycin transport in a liposome-reconstituted system and provide evidence that it functions as a multidrug efflux pump with substrate preferences distinct from those of known efflux pumps. Furthermore, we present cryogenic electron microscopy (cryo-EM) structures of FoeAB in inward- and outward-facing states, which reveal conformational changes associated with nucleotide binding and identify residues important for substrate transport. Collectively, these findings expand the known repertoire of antibiotic-exporting ABC transporters in Gram-positive bacteria and provide structural insight into the underlying transport mechanism.

PMID:
42664038
Bibliographic data and abstract were imported from PubMed on 29 Aug 2026.

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