Relatives discovered: Membrane proteins of cyanobacteria and higher organisms are structurally highly similar
Researchers from the Helmholtz Research Field Information have described a protein involved in the shaping of the cell membrane in cyanobacteria for the first time. This protein, called SynDLP, exhibits structural similarities to proteins previously found only in higher organisms such as animals and plants. It was long believed that such proteins were exclusive to organisms with a nucleus. The discovery suggests that the protein may have already existed in an ancestral cell before the divergence of organisms with and without a nucleus. The research findings have been published in the journal Nature Communications. (Source: Forschungszentrum Jülich – Press Releases)
The cells of living organisms are equipped with proteins that are involved in the shaping and remodeling of the cell membrane and thus fulfill important tasks. The cell membrane encloses the cell interior, but is subject to constant changes, for example, due to separations, invaginations or fusions. This also involves various proteins that were long assumed to occur exclusively or predominantly in higher organisms. In the past 10 to 20 years, however, proteins have been identified or predicted to be found even in simple organisms that do not possess a cell nucleus. As part of a research collaboration, a protein involved in membrane remodeling in cyanobacteria has now been described for the first time. The existence of such a bacterial protein was suspected, but proof was still pending. It is probably the bacterial representative of a comparable protein found in higher organisms such as animals and plants.
Membrane proteins also discovered in prokaryotes
Membrane proteins are involved in various cell membrane remodeling processes as well as repair processes to repair membrane damage and thus ensure cell survival. In the past decade, such proteins have also been discovered in prokaryotes – simple organisms that do not have a nucleus. Many of these have similarities to proteins previously thought to be found only in more complex organisms with a nucleus, i.e., the eukaryotes, such as animals and plants.
So-called dynamins and dynamin-like proteins were also originally thought to be a eukaryotic invention until a bioinformatics study in 1999 predicted the existence of bacterial dynamin-like proteins. DLPs – abbreviated from the English term dynamin-like proteins – belong to the dynamin protein superfamily and are involved in various membrane remodeling processes in eukaryotes.
Recently, a dynamin-like protein, SynDLP, has now been found in the genome of a cyanobacterium. This protein was studied by the research team from Johannes Gutenberg University Mainz (JGU) and Forschungszentrum Jülich, with participation from Heinrich Heine University Düsseldorf (HHU). “We previously assumed that we would only find this type of protein in eukaryotic cells,” said Prof. Dr. Dirk Schneider, head of the Membrane Biochemistry group at JGU. “SynDLP has a structure that we previously only knew from higher organisms,” adds Prof. Carsten Sachse, director at the Ernst Ruska Center for Microscopy and Spectroscopy with Electrons, Structural Biology, at Forschungszentrum Jülich and professor at Heinrich Heine University Düsseldorf.
“The structural properties of SynDLP suggest that it is the closest known bacterial ancestor of eukaryotic dynamin,” Carsten Sachse describes the results. “We assume that this protein was already present in a primordial cell before the split into living organisms with and without a nucleus occurred,” adds Dirk Schneider.
Cyanobacteria have an internal membrane system for photosynthesis
Cyanobacteria are among the oldest organisms on earth and are also known as blue-green bacteria because of their color. Unlike other bacteria, they possess a second internal membrane system in which the light reactions of photosynthesis take place. However, precisely because of the light reaction, the membrane is very vulnerable and is subject to constant remodeling. Therefore, corresponding proteins are particularly important for the reconstruction or repair of the membrane.
“We do not yet know exactly what function SynDLP has in membrane dynamics,” says Dirk Schneider. It does not appear to be vital under laboratory conditions. “However, if it were not essential, it would not have been conserved over billions of years,” surmises the chemist from Mainz. In the future, the scientists plan to pursue this question and investigate exactly what function the protein performs in the bacterial cell.
Long-term research cooperation bears fruit
Two young scientists were significantly involved in the eight years of research now published, Lucas Gewehr from JGU and Dr. Benedikt Junglas from Forschungszentrum Jülich, formerly a doctoral student at the Max Planck Graduate Center with Johannes Gutenberg University (MPGC). Other collaborators are from the Max Planck Institute for Polymer Research in Mainz, Germany, and Aarhus University in Denmark. The work was published in the journal Nature Communications.
FZJ/E. Zeiss, 21.04.2023
The original press release can be found at:
Verwandtschaft entdeckt: Membranproteine von Cyanobakterien und von höheren Organismen sind strukturell ähnlich (only in german)
The original publication can be found at (Open Access):
Lucas Gewehr, Benedikt Junglas et al. SynDLP is a dynamin-like protein of Synechocystis sp. PCC 6803 with eukaryotic features. Nature Communications, 14. April 2023, DOI: 10.1038/s41467-023-37746-9
Localization in the Helmholtz Research Field Information:
Helmholtz Research Field Information, Program 3: Materials Systems Engineering Processing, Topic 5: Materials Information Discovery
Contact:
Prof. Dr. Carsten Sachse
Director of the Ernst-Ruska-Centrums for Structural Biology (ER-C-3)
Forschungszentrum Jülich
Phone: +49 2461/61-2030
E-Mail: c.sachse@fz-juelich.de
Contact for this press release:
Erhard Zeiss
Press Officer
Forschungszentrum Jülich
Phone: +49 2461 61-1841
E-Mail: e.zeiss@fz-juelich.de
