Download MendeleyThe cysteine-rich domain of SEP15, a selenoprotein co-chaperone of the ER chaperone, UDP-glucose:glycoprotein glucosyltransferase, adopts a novel fold
Williams, R.V., Guay, K.P., Lesk, O.H., Hebert, D.N., Gierasch, L.M.(2026) J Biol Chem
- PubMed: 42854909 Search on PubMed
- DOI: https://doi.org/10.1016/j.jbc.2026.113629
- Primary Citation Related Structures:
37EI, 9A9H - PubMed Abstract:
Proteins targeted to the secretory pathway are involved in a myriad of biological processes but can only do so when properly folded. Within the endoplasmic reticulum, glycoprotein folding is regulated by the enzyme UDP-glucose:glycoprotein glucosyltransferase (UGGT) and its oxidoreductase partner, the 15-kDa selenoprotein (SEP15 aka SELENOF). The interaction between these two chaperones is poorly understood, limiting understanding of their function. SEP15 is comprised of two domains, a C-terminal thioredoxin-like domain, the structure of which has been reported (PDB 2A4H), and an approximately 50-residue long N-terminal cysteine-rich domain (CRD), of unknown structure. Here, we report the NMR solution structure of SEP15 CRD, which mediates the interaction with UGGT. These data reveal that this domain adopts a dimer in solution and forms a previously undescribed helical fold, stabilized by three disulfide bonds between residues C10-C42, C21-C43, and C24-C39. Furthermore, our results validate a model of the UGGT/SEP15 complex and lay the foundation for future studies of its interaction with glycoprotein substrates.
- Department of Biochemistry & Molecular Biology, University of Massachusetts Amherst, Amherst, MA 01003.
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