Marcel Bruchez

Associate Research Professor of Chemistry and Program Manager, Technology Center for Networks and Pathways

A fundamental gap in our basic biological knowledge exists at the interface between mRNA and proteins. We understand many aspects of the ribosome as a molecular machine, and details of the dynamics deep in the ribosome, where the protein is synthesized, are becoming clear. Our knowledge of protein folding, however, has come primarily from purified folded or refolded proteins, lacking any connection to the underlying vectorial synthesis of the proteins carried out by the ribosome with the mRNA as a synthetic program. We are using a novel fluorescence method to address key questions in this process at a single molecule level: How long does it take to translate a single protein? Are all translation events roughly equivalent? Are all ribosomes created equal?  What is the role of translation rate on nascent protein fold and function? Does mRNA secondary structure control translation rates with any functional consequence? Can this be integrated with antisense or chemical agents to directedly derail or promote protein folding?

Our work relies on the integration of 3 key areas to address these problems. Innovations in RNA modification allow us to label and immobilize mRNA in unique ways; a detailed understanding of the impact of ribosome modifications on translational viability allows us to make translation-competent fluorescent ribosomes; and our expertise in fluorescent probe design allows us to label these modified biological systems with bright, photostable dyes. Combining site- specifically modified RNA and ribosomes with single-molecule fluorescence analysis provides a versatile platform for asking many of these fundamental questions.

Lab Webpage: http://bruchez-lab.mbic.cmu.edu/index.php