The interdisciplinary research appears this week in two back-to-back papers in the Proceedings of the National Academy of Sciences.
"Researchers have successfully combined computer modeling and experimental results in folding studies for small proteins, but this is the first effective combination for a large, multi-domain protein," said study co-author Kathleen Matthews, Dean of the Wiess School of Natural Sciences and Stewart Memorial Professor of Biochemistry. "Pioneering efforts were required to establish comparable experimental and theoretical data, and the method worked remarkably well. We expect others to adopt it in their own studies."
Proteins are the workhorses of biology. At any given time, each cell in our bodies contains 10,000 or more of them. Each of these proteins is a chain of amino acids strung end-to-end like beads in necklace. For longer proteins, the chain can contain hundreds of amino acids.
Thanks to modern genomics, scientists can use DNA to decipher the amino acid sequence in a protein. But knowing the sequence gives no clue to the protein's function, because function is inextricably tied to shape, and every protein self-assembles into its characteristic shape within seconds of being created.
"The folded, functional form of the protein is what really matters, and our interest is in creating a folding roadmap of sorts, a plot of the thermodynamic route that the protein follows as it moves toward equilibrium," said co-author Cecilia Clementi, the Norman Hackerman-Welch Young Investigator Assistant Professor of Chemistry.
The Rice research team included Clementi, Clementi's graduate student Payel Das, experimentalist Pernilla Wittung-Stafshede, associate professor of bioche