Serial data collection approaches for radiation sensitive reaction intermediates at ambient temperature

Serial synchrotron crystallography (SSX) is an emerging method that builds on serial femtosecond crystallography (SFX) at XFELs, which our group co-pioneered. In particular, for both SFX and SSX various approaches exist for crystal delivery into the X-ray beam that differ not only in technical complexity and sample consumption but also in the “cleanliness” of the experimental protocol and thus of the diffraction data. The latter is particularly important for SSX with respect to radiation damage. Thus, our BAG proposal has two aspects, a technical one, the implementation and comparison of various sample delivery approaches at ID29, using a highly radiation sensitive metalloprotein model system and a scientific one, the structure determination of a predicted but so far elusive flavin N5-oxide intermediate of the enzyme EncM. Obviously, the technical aspect not only affects the scientific aspect, but also has implications for the community at large using SSX.