This award supports the initiation of an exploratory project whose long term aim is development of equipment and procedures for determination of the three-dimensional atomic structure of proteins that cannot be crystallized. The new equipment will be used to generate a beam of superliquid helium drops, each containing a single hydrated protein molecule. The molecules will be oriented within the drops by use of laser, and an electron diffraction pattern will be generated by passing the drops through a high energy electron beam. Data from individual drops will be combined to provide a diffraction pattern, and then analyzed using recently developed iterative methods. Alternatively, more standard approaches that depend on isomorphous replacement can be used.
The two initial steps to be supported by this award include the development of a molecular-beam source of hydrated proteins in submicron-sized, vitreous ice balls at liquid helium temperature, and the development of an electron diffraction camera and area detector capable of analysis of the jet of the doped ice balls. Laser spectroscopy will be used to confirm that proteins in the ice-balls are not denatured, and the success of the second step will be demonstrated by looking for Debye-Scherrer ring electron diffraction patterns from the proteins in the beam of doped ice balls. The project will provide traing for a postdoctoral student, and will augment the content of existing departmental education outreach efforts.
