idw – Informationsdienst Wissenschaft
Nachrichten, Termine, Experten
Nachrichten, Termine, Experten
Chemistry: Publication in Nature Communications
Biofilms are conglomerates of bacteria and other organisms, which are feared in medicine as well as other areas because they can contain pathogens and are highly resistant to treatment. Chemists at Heinrich Heine University Düsseldorf (HHU) have, in collaboration with colleagues from Munich and Groningen, examined how the polysaccharide “Pel” – a central component of many biofilms – is exported out of the cell by the pathogen P. aeruginosa. In the scientific journal Nature Communications, they describe the structure of the so-called PelBC export complex, which represents the last station in the cell before “Pel” is released.
Bacterial biofilms are common aggregates of cells, which ensure the survival of microorganisms in harsh environments and are highly resistant to mechanical and chemical treatments. They can present a danger to humans where they e.g. cover surfaces of medical devices or in the food industry and harmful organisms can colonise them.
Biofilms enable bacteria to exchange genomic information with each other. This makes it easier for them to develop resistance to antibiotics – when resistant bacteria pass on resistance information to other species. They also facilitate nutrient uptake.
In particular where pathogenic bacteria form biofilms, it is important to understand which mechanisms play a role in their formation. The HHU research group “Synthetic Membrane Systems” headed by Professor Dr Alexej Kedrov has collaborated with colleagues from Ludwig Maximilian University (LMU) in Munich and the University of Groningen in the Netherlands to study this. They have focused on the pathogen Pseudomonas aeruginosa (for short: P. aeruginosa), which can cause e.g. pneumonia, urinary tract infections and meningitis in humans. The pathogen is resistant to multiple antibiotics and a key so-called “hospital germ”.
Professor Kedrov: “In order to form biofilms, the bacteria synthesise and export various biopolymers, above all polysaccharides – specific sugar chains. Despite decades of research, knowledge of how the synthesis or transport takes place remains limited. We have concentrated on the polysaccharide ‘Pel’, which is produced by P. aeruginosa.”
The production of Pel requires a protein machinery comprising several sub-units, which crosses two membranes. Kedrov: “To date, however, neither the structure of the machinery nor its dynamics were known. With the help of cryo-electron microscopy, we can resolve the structure of the PelBC complex in the lipid membranes and identify the path of the Pel polysaccharide.”
Marius Benedens, the lead author, adds: “Our study shows how electrostatic interactions are used in nature to assemble the export complex and enable the transport of the polysaccharide. However, for the cell to survive, the pore cannot remain permanently open for transport. A small conformational change at the end of this pore is therefore necessary – a tiny gate is opened, so to speak.”
With a view to the prospects for application, Kedrov comments: “It is fascinating to see the organisation of a complex structure in such detail. Among other things, it shows how nature solves challenges in protein design, for example the coupling of a symmetrical ring of PelC sub-units to the asymmetrical PelB channel. It may be possible to use our results to block the export of Pel in a targeted manner and thus suppress biofilm formation.”
In the next step, the research group intends to examine this export process in detail. Another involved protein complex, which is responsible for the synthesis of Pel in the cytoplasm of the cell and its transport across the inner membrane, will also be examined in greater detail.
Marius Benedens, Cristian Rosales-Hernandez, Sabine A. P. Straathof, Jennifer Loschwitz, Otto Berninghausen, Giovanni Maglia, Roland Beckmann & Alexej Kedrov. Assembly and the gating mechanism of the Pel exopolysaccharide export complex PelBC of Pseudomonas aeruginosa. Nature Communications 16:5249 (2025).
DOI: 10.1038/s41467-025-60605-8
The research group used cryo-electron microscopy to reconstruct the transport complex within the cel ...
HHU/Alexej Kedrov
Merkmale dieser Pressemitteilung:
Journalisten, Wissenschaftler
Biologie, Chemie, Medizin
überregional
Forschungsergebnisse, Wissenschaftliche Publikationen
Englisch
The research group used cryo-electron microscopy to reconstruct the transport complex within the cel ...
HHU/Alexej Kedrov
Sie können Suchbegriffe mit und, oder und / oder nicht verknüpfen, z. B. Philo nicht logie.
Verknüpfungen können Sie mit Klammern voneinander trennen, z. B. (Philo nicht logie) oder (Psycho und logie).
Zusammenhängende Worte werden als Wortgruppe gesucht, wenn Sie sie in Anführungsstriche setzen, z. B. „Bundesrepublik Deutschland“.
Die Erweiterte Suche können Sie auch nutzen, ohne Suchbegriffe einzugeben. Sie orientiert sich dann an den Kriterien, die Sie ausgewählt haben (z. B. nach dem Land oder dem Sachgebiet).
Haben Sie in einer Kategorie kein Kriterium ausgewählt, wird die gesamte Kategorie durchsucht (z.B. alle Sachgebiete oder alle Länder).
