Using Synchrotron Spectroscopy to Understand How a Protein Evolves
A major challenge in research to enable large-scale production of biofuels is developing enzymes that are highly efficient in converting biomass components into usable fuels. Enzymes are proteins that are configured to catalyze such conversions. Many protein structures are known, including those of many valuable enzymes. Much less is known about how small changes in a protein’s composition can change its three-dimensional structure and control its catalytic efficiency, or even convert a protein with no catalytic function into one that is an efficient catalyst. New research shows the structural basis for conversion by directed evolution of a non-catalytic small protein into an enzyme that is an effective catalyst for linking RNA molecules. The scientists used an Extended X-ray Absorption Fine Structure (EXAFS) station at the Stanford Synchrotron Radiation Lightsource (SSRL) to determine the active-site structure of the newly synthesized enzyme. The EXAFS experiments were able to show the exact chemical environment of each zinc atom in the new enzyme, leading to an explanation of why it had developed the catalytic activity. The research was carried out by a team of scientists from the University of Minnesota and SSRL and is published in Nature Chemical Biology.
Chao, F.-A., et al., 2013. “Structure and Dynamics of a Primordial Catalytic Fold Generated by In Vitro Evolution,” Nature Chemical Biology 9, 81–83. DOI: 10.1038/nchembio.1138.