In-house UV radiation-damage-induced phasing of selenomethionine-labeled protein structures.
Selenomethionine labeling is the most common technique used in protein
crystallography to derivatize recombinant proteins for experimental phasing
using anomalous scattering at tunable synchrotron beamlines. Recently, it has
been shown that UV radiation depletes electron density of selenium atoms of
selenomethionine residues and that UV radiation-damage-induced phasing
(equivalent to single isomorphous replacement) protocol can be applied to
calculate experimental phases. Here we present the straightforward integration
of a UV source with an in-house diffractometer. We show how this setup can
extend the capabilities of a sealed tube X-ray generator and be used for
experimental phasing of selenium-labeled proteins.