Human SELENOF is an endoplasmic reticulum (ER) selenoprotein that contains the redox active motif CXU (C is cysteine and U is selenocysteine), resembling the redox motif of thiol-disulfide oxidoreductases (CXXC). Like other selenoproteins, the challenge in accessing SELENOF has somewhat limited its full biological characterization thus far. Here we present the one-pot chemical synthesis of the thioredoxin-like domain of SELENOF, highlighted by the use of Fmoc-protected selenazolidine, native chemical ligations and deselenization reactions. The redox potential of the CXU motif, together with insulin turbidimetric assay suggested that SELENOF may catalyze the reduction of disulfides in misfolded proteins. Furthermore, we demonstrate that SELENOF is not a protein disulfide isomerase (PDI)-like enzyme, as it did not enhance the folding of the two protein models; bovine pancreatic trypsin inhibitor and hirudin. These studies suggest that SELENOF may be responsible for reducing the non-native disulfide bonds of misfolded glycoproteins as part of the quality control system in the ER.
Bibliographical noteFunding Information:
We thank Mrs. Ricki Notis Dardashti and Dr. Shailesh Kumar for technical assistance and helpful discussions. Z.Z. is grateful for a CSC fellowship. R.M. acknowledges the support of the VATAT scholarship for Arab students. N.M. acknowledges financial support from the Israel Science Foundation (783/18).
© 2022 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH
- chemical protein synthesis
- protein folding
- redox potential