HOUSTON (Aug. 13, 2014) Nature's artistic and engineering skills are evident in proteins, life's robust molecular machines. Scientists at Rice University have now employed their unique theories to show how the interplay between evolution and physics developed these skills.
A Rice team led by biophysicists Peter Wolynes and Jos Onuchic used computer models to show that the energy landscapes that describe how nature selects viable protein sequences over evolutionary timescales employ essentially the same forces as those that allow proteins to fold in less than a second. For proteins, energy landscapes serve as maps that show the number of possible forms they may take as they fold.
The researchers calculated and compared the folding of natural proteins from front to back (based on genomic sequences that form over eons) and back to front (based on the structures of proteins that form in microseconds). The results offer a look at how nature selects useful, stable proteins.
In addition to showing how evolution works, their study aims to give scientists better ways to predict the structures of proteins, which is critical for understanding disease and for drug design.
The research reported this week in the Proceedings of the National Academy of Sciences shows that when both of the Rice team's theoretical approaches -- one evolutionary, the other physics-based -- are applied to specific proteins, they lead to the same conclusions for what the researchers call the selection temperature that measures how much the energy landscape of proteins has guided evolution. In every case, the selection temperature is lower than the temperature at which proteins actually fold; this shows the importance of the landscape's shape for evolution.
The low selection temperature indicates that as functional proteins evolve, they are constrained to have "funnel-shaped" energy landscapes, the scientists wrote.
|Contact: David Ruth|