Digital ion trap mass spectrometer for probing the structure of biological macromolecules by gas phase X-ray scattering.

Small-angle X-ray scattering is a technique for the characterization and structural analysis of a variety of materials including biological macromolecules and polymers. For the conformational analysis of proteins, the interaction between sample and X-rays is generally performed when the proteins are present in solution. Here a three-dimensional digital ion trap interfaced with a high intensity X-ray source is built to prove that X-ray scattering can be performed on ions isolated in gas-phase.

On-line optical and X-ray spectroscopies with crystallography: an integrated approach for determining metalloprotein structures in functionally well defined states.

X-ray-induced redox changes can lead to incorrect assignments of the functional states of metals in metalloprotein crystals. The need for on-line monitoring of the status of metal ions (and other chromophores) during protein crystallography experiments is of growing importance with the use of intense synchrotron X-ray beams. Significant efforts are therefore being made worldwide to combine different spectroscopies in parallel with X-ray crystallographic data collection.