Location: SCL 160
Join the Yale Chemistry Department for a Biophysical Chemistry seminar with Dr. Magnus Wolf-Watz, from the Umea Unversity in Sweden.
Abstract: Rational design of enzyme catalyzing novel chemical reactions is one of the outstanding goals in contemporary protein science that, so far, only has been partially realized and then mostly for “simple” elimination reactions. Therefore, and in order to reach this goal experimental approaches that can uncover new and fundamental principles in enzymatic catalysis, including understanding of both binding and the chemical step are needed. In my lab we are utilizing evolutionary “time-travel” both backwards and forward in time for fundamental discoveries observed through a lens of biophysical and structural studies. For backwards looking we are exploiting the discovery of the Asgard archaea that are believed to be the closest known relatives to eukaryotic cells. From a comparative approach with Adenylate kinases isolated from Odinarchaeota, E.coli and human we have uncovered the molecular underpinning of enzymatic multi-selectivity and an unexpected oligomerisation dependency of an active site. Further, we have uncovered new insight into the role of magnesium ions in catalysis of the adenylate kinase reaction (ATP + AMP <-> 2ADP). For forward looking we utilize directed evolution based on bacterial display to develop low molecular weight proteins that can bind to antibodies in a tunable fashion. Through experiments with both negative and positive selection pressures we were able to identify binders that are molecular switches with clear “on” or “off” behavior in response to calcium binding. Solution state NMR experiments revealed that the calcium free “off” state has a partially disordered antibody binding epitope that was restored by calcium to generate a fully functional “on” state. Therefore, the calcium-switch in our designed protein is controlled by a “coupled folding and binding” mechanism, a principle that has evolved over and over again under natural selection in for instance intrinsically disordered proteins. Our design contributes a principle that can be utilized broadly for cases where tunable activity is desirable. In summary our approach with backwards and forward looking has enabled us to contribute fundamental understanding of both catalysis and binding, both of which are required for rational design of novel enzymes.