Fig. 3. The usherin fusion peptides appear to be properly folded. (A) Usherin fusion peptides were fractionated by PAGE on 15% SDS (denatured) or non-SDS (non-denatured) gels under reducing or non-reducing conditions. (B) Five micrograms of recombinant usherin (ush) or the indicated peptides were analyzed for free sulfhydryl groups under reducing and non-reducing conditions using the Thiol and Sulfide Quantitation Kit (Molecular Probes, Eugene, OR). Free sulfhydryls result in the formation of a colored product with an absorption maxima at 410 nm, which is quantified spectrophotometrically.