Ruprecht-Karls-Universität Heidelberg

Open positions in the Pfeffer Lab

2 PhD student positions:
Cryo-EM analysis of the co-translational machinery for protein folding and maturation in prokaryotes (first position) / eukaryotes (second position)

Co-translational folding and maturation of proteins require an intricate network of folding chaperones and processing enzymes that act on the growing nascent protein in a co-translational manner. Structural information on ribosome-nascent chain-chaperone complexes is sparse, because the involved interactions are mostly transient, labile and possibly highly flexible. This renders the involved assemblies inaccessible to classical reductionist structural biology approaches that rely on extensive biochemical purification and require conformationally homogenous particle populations for averaging. We consequently pursue a different approach and image these processes using cryo electron tomography (cryo-ET)-based strategies, which can reveal the three-dimensional arrangement of individual macromolecules even in crowded native microenvironments at molecular resolution and therefore render extensive biochemical purification unnecessary. This approach allows us to analyze the three-dimensional spatial distribution of ribosomes, chaperones and processing enzymes for individual native polysomal assemblies under conditions that preserve the labile and transient interactions governing co-translational protein folding and maturation.

The project:
The central objective of this project will be to study defined polysomal assemblies engaged in the synthesis of model substrates. Cryo-ET approaches will be used to visualize these assemblies in both a non-cellular context and in sections of vitrified unperturbed cells obtained using focused ion beam (FIB) milling.
Methods that will be used:
High-resolution cryo electron microscopy and tomography approaches; advanced image processing; standard biochemical, molecular and cell biology methods

The candidate:
We are looking for a highly motivated PhD student holding a Master’s degree in life sciences with a strong background in computational biology. Experience in electron microscopy is of advantage, but not required. For further information and application please visit the “Open PhD positions” section of our graduate school HBIGS: