Folding Protein Ions in the Gas-Phase
Monday, March 6, 4:00 PM MoSE 1201 A
Kenneth J. Laszlo
Ph.D. Candidate
Bush Group
University of Washington
The
structure and folding of a protein in solution depends on noncovalent
interactions within the protein and those with surrounding ions and
molecules. Decoupling these interactions in solution is challenging,
which has hindered the development of accurate physics-based models for
structure prediction. Investigations of proteins in the gas phase can be
used to selectively decouple factors affecting the structures of
proteins. Here, we use cation-to-anion proton-transfer reactions (CAPTR)
to reduce the charge states of denatured ubiquitin ions in the gas
phase, and ion mobility to probe their structures. In CAPTR, a precursor
charge state is selected and reacted with monoanions to generate
charge-reduced product ions. Following each CAPTR event, denatured
ubiquitin ions (13+ to 6+) yield products that rapidly isomerize to
structures that have smaller collision cross sections. We also show
similar results for poly-ubiquitin ions and use coarse grain modeling to
establish possible structures. These results show that CAPTR strongly
complements existing techniques for characterizing the structures and
dynamics of biological molecules in the gas phase.
Kenneth J. Laszlo is
a graduate of the Fernandez lab at Georgia Tech. The discussion
following the talk will focus on the GT alumni experience of graduate
research.
