Skip to main content
Open Access Publications from the University of California

Advancements and Application of Microsecond Synchrotron X-ray Footprinting at the Advanced Light Source


The method of synchrotron X-ray protein footprinting (XF-MS) is used to determine protein conformational changes, folding, protein-protein and protein-ligand interactions, providing information which is often difficult to obtain using X-ray crystallography and other common structural biology methods [1–3]. The technique uses comparative in situ labeling of solvent-accessible side chains by highly reactive hydroxyl radicals (•OH) in buffered aqueous solution under different assay conditions. In regions where a protein is folded or binds a partner, these •OH susceptible sites are inaccessible to solvent, and therefore protected from labeling. The •OH are generated by the ionization of water using high-flux-density X-rays. High-flux density is a key factor for XF-MS labeling because obtaining an adequate steady-state concentration of hydroxyl radical within a short irradiation time is necessary to minimize radiation-induced secondary damage and also to overcome various scavenging reactions that reduce the yield of labeled side chains.

Main Content
For improved accessibility of PDF content, download the file to your device.
Current View