After protein production, many proteins are equipped with attachments such as sugar residues in order to perform their tasks properly. This process is directly coupled to the transport across a membrane.
Many protein complexes are involved in protein synthesis.Through the ER translocon (green, blue and red) the newly synthesized protein is transported across the membrane (gray).
Graphic: Friedrich Förster / Copyright: MPI of Biochemistry
Employing various methods of structural biology, scientists at the Max Planck Institute (MPI) of Biochemistry in Martinsried near Munich, Germany, have now gained insights into the architecture of the protein complex (ER translocon) responsible for this process. The results of the joint project have now been published in Nature Communications.
Producing a protein is a highly intricate process for the cell and involves many individual steps. Depending on the purpose for which a protein is used, there are different sites for protein production: the cytoplasm or the endoplasmic reticulum (ER). The ER is separated by a membrane from its surroundings in the cytoplasm. Even before protein synthesis is completed, the proteins produced at the ER enter via its membrane into the interior of the ER and are modified through the attachment of sugar residues concomitantly. Without these attachments, the proteins would not be able to fold properly and thus would not fulfill their functions in the cell.
Scientists of the research group “Modeling of Protein Complexes” have now described the architecture of the protein complex responsible for the transport and modification of the newly produced protein: the ER translocon. “It is located in the membrane of the ER, and this fact, together with its size and complex composition, has greatly hampered previous structural studies,” says Friedrich Förster, group leader at the MPI of Biochemistry, describing the initial situation. The structures of many subunits and their arrangement in the native ER translocon have thus far remained elusive.
It was not until cryoelectron tomography came into use that researchers could gain first insight into the architecture of the translocon. The sample is “shock frozen” to preserve its natural structure. Using an electron microscope, the scientists capture two-dimensional images of the object from different perspectives, from which they then reconstruct a three-dimensional image. Further investigations have made it possible to identify individual modules in the structure. Among them is the module that attaches the sugar residues to the newly produced protein.
“Based on this method, we will now try to determine the structure and location of other components of the ER translocon," says Förster. If the researchers know the individual structures of the ER translocon and their arrangement in the complex, they can indirectly draw conclusions about the precise functions and interactions of all components.
Doi: 10.1038/ncomms4072 (2013).Contact
Anja Konschak | Max-Planck-Institut
One step closer to reality
20.04.2018 | Max-Planck-Institut für Entwicklungsbiologie
The dark side of cichlid fish: from cannibal to caregiver
20.04.2018 | Veterinärmedizinische Universität Wien
University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.
Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.
Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...
Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.
The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...
Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.
Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...
In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...
13.04.2018 | Event News
12.04.2018 | Event News
09.04.2018 | Event News
20.04.2018 | Physics and Astronomy
20.04.2018 | Interdisciplinary Research
20.04.2018 | Physics and Astronomy