A study published in Nature Communications reveals, at near-atomic resolution, how a bacterial protein contorts itself to switch on the very genes that allow a cell to split in two — and why this discovery may open an entirely new front in the fight against antibiotic resistance.
The ability of a cell to divide is, in the most literal sense, the engine of life. Without division, there is no growth, no repair, no reproduction — and no infection. It is therefore remarkable that, despite decades of molecular biology, the precise mechanism by which bacteria orchestrate the genetic program of their own proliferation had, until recently, remained largely inferred rather than observed. A research team led by David Reverter at the Universitat Autònoma de Barcelona (UAB), working in collaboration with the ALBA synchrotron and the cryo-electron microscopy facility of the Institut de Génétique et de Biologie Moléculaire et Cellulaire in Strasbourg, has now changed that. Their findings, published in Nature Communications, describe with extraordinary structural detail how the transcription factor MraZ — a protein encoded by the first gene of the dcw operon in most bacteria — binds to the promoter DNA that triggers cell division [1].
In most bacteria, the division and cell wall gene cluster, known as the dcw operon, is regulated by MraZ, a highly conserved DNA-binding transcriptional regulator whose structural basis for activating the operon had remained unclear. Reverter’s team addressed this gap by determining three distinct cryo-EM structures of MraZ in complex with the upstream promoter region of the dcw cluster, derived from Mycoplasma genitalium — a species chosen precisely because of its exceptionally streamlined genome. The promoter region contains four repeated six-nucleotide binding boxes, and the structures, resolved at resolutions between 3.36 and 3.87 ångströms, reveal the specific contacts between MraZ’s DNA-binding motif and the nucleobases of each box.
What emerged from this near-atomic view was surprising. MraZ normally exists as an octamer — eight identical subunits arranged in a ring — whose natural curvature is geometrically incompatible with wrapping around the four promoter boxes simultaneously. To make contact with all four binding sites, the octamer must undergo a structural distortion, exposing a cradle-like DNA-binding motif that presents three highly conserved basic residues — Lys13, Arg15, and Arg86 — essential for anchoring to the consensus promoter sequence. In other words, the ring must partly break and reshape itself before the genes for bacterial division can be switched on. Prior understanding of this regulatory event had rested almost entirely on biochemical assays and computational modelling; this is the first time the interaction has been captured at structural resolution.
The therapeutic implications are considerable. The regulatory mechanism appears to be universal across most bacteria, since MraZ proteins share the same octameric architecture and the promoter sequences of cell division operons are highly conserved across species [2]. This universality makes MraZ a compelling candidate target for future antimicrobial strategies: a molecule capable of locking the protein in its ring conformation — preventing the structural distortion required for DNA binding — could, in principle, arrest bacterial proliferation without engaging the classical targets that resistant strains have already learned to circumvent. Such an approach would belong to an entirely different mechanistic category from existing antibiotics, a prospect of obvious relevance at a time when drug-resistant infections are claiming an increasingly intolerable human toll.
Paolo Rega
References
- Sánchez-Alba, L., Varejão, N., Durand, A. et al. Structural basis for transcriptional regulation by the cell division regulator MraZ in Mycoplasma genitalium. Nat Commun 17, 2132 (2026). https://doi.org/10.1038/s41467-026-68809-2
- Technology Networks. (2026, February 18). Structural study reveals MraZ role in cell division. Technology Networks. https://www.technologynetworks.com/analysis/news/molecular-mechanism-regulating-bacterial-cell-division-discovered-409807
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