Ruprecht-Karls-Universität Heidelberg
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Mogk0118 - Scientist (f/m) / PhD position
Project no:
Mogk0118

Project leader:

Project supervisor:
Mogk, Axel
Application deadline:
31. Dec 2018
Start of PhD project:
1. Jan 2019

Project description:

Title:
Structural and mechanistic basis of stand-alone disaggregase conferring superior heat resistance
Summary:
Environmental stress conditions cause protein misfolding and ultimately protein aggregation. The reactivation of aggregated proteins by molecular chaperones is essential for the survival of cells during severe heat stress. Heat resistance is provided by AAA+ disaggregases, which represent ring-forming machines that extract polypeptides from protein aggregates by an ATP-driven threading activity. The classical AAA+ disaggregase ClpB needs to cooperate with an Hsp70 partner chaperone during disaggregation for targeting to protein aggregates and stimulation of ATPase activity. We recently identified a novel AAA+ disaggregase, ClpG, which does not require assistance by Hsp70. ClpG functions as stand-alone and most efficient disaggregase and confers superior heat resistance to bacteria. Thereby ClpG promotes bacterial survival during temperature-based sterilization methods used in modern food production and medical sterilization procedures and contributes to bacterial persistence in e.g. the hospital environment.
The project aims at the detailed mechanistic understanding of ClpG disaggregation activity. How does ClpG specifically recognize protein aggregates? How is aggregate binding coupled to control of ATPase and threading activities? How does ClpG cooperate with evolutionary co-organized chaperones? Can ClpG also provide superior heat resistance to eukaryotic cells? The study will provide important insights into disaggregase function and can provide basis for rationale drug design.
References:
Lee C, Franke KB, Kamal SM, Kim H, Lunsdorf H, Jager J, Nimtz M, Trcek J, Jansch L, Bukau B, Mogk A, Romling U (2018) Stand-alone ClpG disaggregase confers superior heat tolerance to bacteria. Proc Natl Acad Sci U S A 115: E273-E282

Mogk A, Bukau B, Kampinga HH (2018) Cellular Handling of Protein Aggregates by Disaggregation Machines. Mol Cell 69: 214-226

Carroni M, Franke KB, Maurer M, Jager J, Hantke I, Gloge F, Linder D, Gremer S, Turgay K, Bukau B, Mogk A (2017) Regulatory coiled-coil domains promote head-to-head assemblies of AAA+ chaperones essential for tunable activity control. eLife 6
Methods that will be used:
We plan to determine the structure of the N-terminal domain of ClpG, which mediates the binding to protein aggregates, by X-ray crystallography or NMR spectroscopy. The aggregate binding site will be validated by site-specific crosslinking experiments and designed mutants that will be characterized by a multiplicity of biochemical and cell biological methods. ClpG conformational dynamcis and impact of ATP and substrate binding will be monitored by H/D exchange experiments couple to mass spectrometry
Cooperation partners:
Irmgard Sinning (BZH, Heidelberg), Marta Carroni (SciLifeLab, Stockholm), Ute Römling (Karolinska Institute, Stockholm)
Personal qualifications:
We seek for a person with great interest in fundamental research.
Keywords:
chaperone, protein structure, protein aggregates, heat resistance