Copyright information:Taken from "Characterization of the SECIS binding protein 2 complex required for the co-translational insertion of selenocysteine in mammals"Nucleic Acids Research 2005;33(16):5172-5180.Published online 9 Sep 2005PMCID:PMC1214547.© The Author 2005. Published by Oxford University Press. All rights reserved () A sample of 75 µg of C-terminal or full-length SBP2 as indicated was resolved by Sephadex 200 gel filtration chromatography. Fractions were analyzed by SDS–PAGE followed by Coomassie staining and densitometry. The density peaks were aligned with their corresponding position on overlaid chromatograms of the proteins used as standards (top). Calculated molecular weights for Strep-tagged CTSBP2 (ST-CTSBP2), Xpress/His-tagged C-terminal SBP2 (amino acids 399–846; XH-CTSBP2) and Xpress/His-tagged full-length SBP2 (XH-FLSBP2) in the presence (+salt) or absence of 1 M NaCl are shown on the right. () Samples of 10 ng of each type of SBP2 (as indicated) were added to a reticulocyte lysate assay containing luciferase mRNA with a Sec codon at position 258 and a wild-type GPX-4 SECIS element inserted in the 3′-untranslated region. The average luciferase activity (±SD) is shown for each version of SBP2. The data for the fourth column are from a reaction lacking any added SBP2. () The data in B re-plotted as luminescence units per fmol of SBP2.