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 Associate Professor B.S. 1988, 'La Sapienza' University, Rome, Italy M.S. 1990, University of Arizona Ph.D. 1996, California Institute of Technology Room: 5351aPhone: 608-262-5430 Email: cavagnero@chem.wisc.edu Position: Associate Professor Selected Publications
| Research DescriptionHow does a protein with a given amino acid sequence manage to achieve its bioactive and amazingly organized three-dimensional structure? This process, known as protein folding, is one of the most fundamental yet poorly understood events in chemistry and biology. Most studies performed in the past have focused on the in vitro folding of full-length biopolymers starting from unfolded states generated by high concentrations of denaturants or high temperature. However, these types of unfolded states rarely exist in living cells! Moreover, polypeptide chains start sampling conformational space (and possibly even fold) way before the protein amino acid sequence has been fully synthesized, during a process known as translation. In order to fully understand protein folding, it is therefore important to take the cellular context into account. This is even more important in the case of protein misfolding, i.e., folding gone wrong, which leads to protein aggregation and several deadly neurodegenerative and brain disorders such as Alzheimer's disease, spinocerebellar ataxia and Huntington's chorea. Thus, understanding protein folding/misfolding will lead to both fundamental knowledge and long-term benefits to human health. The Cavagnero group specializes in the high resolution understanding of the fundamental principles of protein folding and misfolding in the cell. We place particular emphasis on understanding folding as nascent proteins emerge from the molecular machine responsible for their biosynthesis, the ribosome. All the studies are performed under physiologically relevant conditions in crowded aqueous media.
Model studies: the structural aspects of polypeptide chain elongation. We study the conformation and dynamics of purified N-terminal polypeptides of increasing length to follow how protein conformation is modulated by chain elongation. This project involves a combination of spectroscopy and computation.
Model studies and fundamental questions in protein folding.
Cotranslational protein folding: conformation of ribosome-bound nascent polypeptides. We are developing novel methodologies to follow the cotranslational folding of ribosome-bound nascent polypeptides. This work is based on ime-resolved fluorescence and mass spectrometry-detected H/D exchange in cell-free systems. We have also developed three novel NMR pulse sequences that facilitate high resolution protein analysis in cell-free systems by DOSY-based diffusion filtering.
The role of molecular chaperones in protein folding and misfolding. Both the research directions outlined in sections 1 and 2 are pursued in the absence and presence of cotranslationally- active chaperones. We are also performing model studies with purified chaperones such as Hsp70, to specifically explore whether chaperones act merely by preventing misfolding or play an active role in the folding of their substrate. This work is carried out primarily by multidimensional NMR on 15N- and 13C-enriched polypeptide substrates and involves both high resolution kinetics and structural/dynamic analysis. We are also exploring the role of molecular chaperones in human neurodegenerative diseases.
Development of novel spectroscopic techniques to study the folding of nascent polypeptides emerging from the ribosome. The high resolution structural and dynamic analysis of nascent polypeptides emerging from the ribosome in the cellular environment is extremely challenging. The naturally occurring low concentrations of ribosomes and nascent chains demand very high sensitivity. On the other hand, the complexity of the cellular milieu requires an approach able to selectively identify the molecule of interest. Finally, the lack of a
well-defined structure and the presence of dynamic constraints imposed by the ribosome limit the scope and applicability of most known high resolution techniques. We aim at overcoming the above limitations by expanding the traditional boundaries of some classical techniques used for structural analysis in solution. Current method development efforts are underway, particularly in the area of multidimensional NMR, MALDI mass spectrometry and time-resolved fluorescence in the frequency domain. Last Updated: March 4, 2009
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The goals of the group are to: 
