The recombinant Ylr456w, Ypr172w and Pdx3 proteins are folded and form dimers.

<p>(A) SDS-PAGE of each purified recombinant protein. (B) Circular dichroism comparing the secondary structure content of the purified proteins. Protein concentration was 40 μM and spectra were generated at 25°C. (C) General aspect of the protein samples at 40 μM. Note that purified Pdx3 presents the characteristic yellow color of proteins that are bound to FMN. Ylr456w and Ypr172w preparations were colorless. (D) Size-exclusion chromatography of 10 μM Ylr456w, Ypr172w and Pdx3 in Superdex 75 3.3/300 column. The injected volume was 10 μL for each sample. The column was calibrated using transthyretin tetramers (54 kDa) and chymotrypsin monomers (25 kDa). The main panel shows tryptophan fluorescence emission at 320 nm (Ex = 280 nm). Inset shows FMN fluorescence emission at 520 nm (Ex = 450 nm). Ypr172 data are shown in blue; Ylr456w in green and Pdx3 in red. All experiments were repeated at least twice with different proteins batches with similar results. A representative result of each experiment is shown.