October 19, 2022
Dissection of the Mechanism of Protein Folding and Proteolysis by the Molecular Motor ClpXP via Single-Molecule Manipulation
In the past three decades, optical tweezers have been a powerful tool to explore the dynamics of biological macromolecules such as DNA, RNA, proteins, and molecular machines at the single-molecule level. Proteins are responsible for almost every task inside the cell such as cell motility, genome duplication, and chromosome formation. Via an unknown mechanism, proteins must fold to attain their tri-dimensional active structure and, after carrying out their specific function, they are degraded by the proteolytic machinery. What is the mechanism of protein folding? How can this mechanism help us to understand the molecular basis of protein misfolding diseases? And ultimately, how are proteins degraded by the proteolytic machinery? To answer these questions, I developed single-molecule methods using high-resolution optical tweezers to study in great detail the mechanism of protein folding of a model globular protein, to dissect the crucial interactions of the medically relevant huntingtin protein to understand the key elements involved in amyloid formation causing Huntington disease, and finally to unravel the mechanism of action of the proteolytic machinery ClpXP for efficient force generation for protein unfolding and degradation.
Robert Sosa is a sixth-year in the Biophysics graduate group and is mentored by Prof. Carlos Bustamante. Robert's research has focused on developing methods to dissect the molecular mechanism of protein folding and studying the proteolysis process via single-molecule manipulation using optical tweezers.