Background:
First developed in the 1990’s at the National Synchrotron Light Source, xray
synchrotron footprinting is an ideal technique for the analysis of solution-state structure and
dynamics of macromolecules. Hydroxyl radicals generated in aqueous samples by intense x-ray
beams serve as fine probes of solvent accessibility, rapidly and irreversibly reacting with solvent
exposed residues to provide a “snapshot” of the sample state at the time of exposure. Over the last
few decades, improvements in instrumentation to expand the technology have continuously pushed
the boundaries of biological systems that can be studied using the technique.
Conclusion:
Dedicated synchrotron beamlines provide important resources for examining fundamental
biological mechanisms of folding, ligand binding, catalysis, transcription, translation, and
macromolecular assembly. The legacy of synchrotron footprinting at NSLS has led to significant
improvement in our understanding of many biological systems, from identifying key structural
components in enzymes and transporters to in vivo studies of ribosome assembly. This work continues
at the XFP (17-BM) beamline at NSLS-II and facilities at ALS, which are currently accepting
proposals for use.