This proposal describes research whose long-term aim is to determine the threedimensional structure of viruses at atomic resolution. Methods currently in use for structure determination of viruses require crystallization (X-ray diffraction) or lack atomic resolution and require difficult sample preparation and data analysis (Cryo EM and AFM). So far the structure of less 20 viruses has been solved to atomic resolution by X-ray crystallography. Using the high intensity X-ray radiation pulses generated at the X-ray free electron laser facility LCLS in Stanford, diffraction patterns from single virions can be obtained. Due to the short X-ray pulse duration of 10 - 100fsec, each virus particle generates a diffraction pattern before radiation damage destroys the particle. The virus particles will be injected into the X-ray beam via two methods: 1. An electrospray or nebulizer aerosol injector with aerodynamic particle focusing, which has been developed at LLNL and has already been tested at the soft X-ray free electron laser FLASH in Hamburg, Germany. 2. An aerojet source developed at ASU, which provides a monodirectional beam of droplets containing the viruses. The electrospray source delivers dehydrated particles at low particle density, whereas the aerojet source delivers fully hydrated samples with high particle density to the X-ray beam. The aerojet source may even be synchronized with the FEL pulses for higher detection efficiency. After each X-ray pulse a single particle diffraction pattern is read out. These patterns from many particle orientations will be classified, sorted, merged and phased to form a three-dimensional electron charge density map of the virus.
|Effective start/end date||8/1/09 → 7/31/11|
- NSF: Directorate for Biological Sciences (BIO): $299,084.00