Main content

"Men / Women wanted for hazardous journey...

...Small wages. Bitter cold. Long months of complete darkness. Constant danger. Safe return doubtful. Honour and recognition in case of success."

Newspaper advertisement popularly attributed to Sir Ernest Henry Shackleton for one of his Antarctic Expeditions.

Eukaryotic Ribosomes

Ribosomes are molecular machines, which catalyze the translation of genetic information into proteins. They consist of two unequal subunits (small subunit and large subunit), both of which are large assemblies consisting of ribosomal RNA (rRNA) and ribosomal proteins. While the structure and function of bacterial ribosomes is well understood, thanks largely to experiments guided by atomic structures, little is known about the more complex structure and function of eukaryotic ribosomes. Ribosomes of eukaryotic cells are significantly larger than bacterial ribosomes. While bacterial ribosomes have a molecular mass of 2.6MDa, eukaryotic ribosomes consist of a small 40S and a large 60S subunit and are almost twice as large with a molecular mass of 4.3MDa. Eukaryotic ribosomes are also more complex as they contain 45 additional ribosomal proteins. Furthermore, the translation initiation process in eukaryotes is very different compared to bacterial and is highly regulated in a number of cellular processes including development, differentiation, stress response, and neuronal function and consequently many diseases, including cancer and metabolic disorders, are connected with improper functioning or regulation of the initiation of protein synthesis. Find out more about the recent results on eukaryotic ribosomes.

Mitochondrial Ribosomes

Mitochondria are organelles that are responsible for energy conversion in eukaryotic cells. Because they originated from a free-living bacterial ancestor by endosymbiosis, mitochondria still contain ribosomes, which have undergone extensive structural and compositional change throughout evolutionary time. Most notably, mitochondrial ribosomes have acquired a large number of mitochondrial-specific ribosomal proteins, and the mitoribosomal RNA has been shortened dramatically in some organisms, including mammals. Mammalian mitoribosomes are also highly functionally specialized, synthesizing exlusively membrane proteins that form parts of the highly important protein complexes of the mitochondrial respiratory chain. Find out about our recent progress in understanding mitoribosomal structure.  

New Nomenclature for Ribosomal Proteins

The fact that many ribosomal proteins from different species carry the same name, although often unrelated in structure and function, leads to confusion in the research community. With several structures of eukaryotic cytoplasmatic and mitochondrial ribosomes now available at atomic level, it is now possible to unambiguously assign each protein to a family based on structural homology to bacterial and archaeal proteins. In order to eliminate the naming discrepancies, a consortium of structural biologists and biochemists proposed a new naming system for ribosomal proteins that is universally applicable and also takes into account the historical names wherever possible. Comparison tables and Pymol sessions for visualization are maintanined on our web site.  

Prokaryotic Protein Synthesis

With the aim to better understand the molecular machinery involved in co-translational protein folding, processing and targeting of proteins to the membranes we investigated ribosomal complexes with chaperones, nascent chain processing enzymes, the signal recognition particle, and the translocon. Find out more about these ribosomal complexes.

Large Cellular Assemblies and Multienzymes

We are interested in understanding structure and function of large cellular assemblies in general. We investigated large cellular assemblies involved in fatty acid sythesis as a paradigm for understanding how multienzymes shuttle substrates from one active site to another. These results have implications for understanding substrate handover in other multienzymes such as polyketide synthases and nonribosomal peptide synthetases. Find out about the architecture of fatty acid synthases.

We also investigated large assemblies involved in encapsulation of enzymes and pore forming toxins. 


Page URL:
Sun Nov 29 01:10:58 CET 2015
© 2015 Eidgenössische Technische Hochschule Zürich