Phasing Native Biological Molecules at SSRL

Phasing of native biological molecules uses the anomalous scattering properties of Sulfur (S) and Phosphorous (P) at low energy. Recent renewed interest in native molecules phasing resulted in building specialized beamlines capable to do 2.1 keV data collection. Many groups are also working on improving protocols for data aquisition and extraction of the small anomalous signals from S or P.

SSRL has 4 beamlines suitable for low energy phasing at 6-7 keV.  Here we will report on our recent advancements in performing such experiments. The learned lessons are applicable for all types of phasing.