Resolving the bacterial selenomethionyl proteome for differential expression proteomic analysis

The utilization of selenomethionine (SeMet) as a phasing tool coupled with multi‐wavelength anomalous diffraction has allowed the solution of a multitude of three‐dimensional structures in the last two decades since its development. However, cell growth is often hampered when SeMet is provided as the sole source of authentic methionine in growth cultures, and some purified recombinant selenoproteins have proven to have reduced activity and/or altered three‐dimensional structures. As a first step toward identifying which specific selenoproteins hamper cell growth, the bacterial selenomethionyl proteome has been resolved by a combination of cation and anion chromatographic separation followed with SDS‐polyacrylamide gel electrophoresis.