Peptide Binding by Catalytic Domains of the Protein Disulfide Isomerase-Related Protein ERp46.
Funkner, A., Parthier, C., Schutkowski, M., Zerweck, J., Lilie, H., Gyrych, N., Fischer, G., Stubbs, M.T., Ferrari, D.M.(2013) J Mol Biol 425: 1340-1362
- PubMed: 23376096 
- DOI: https://doi.org/10.1016/j.jmb.2013.01.029
- Primary Citation of Related Structures:  
3UJ1 - PubMed Abstract: 
The protein disulfide isomerase (PDI) family member ERp46/endoPDI/thioredoxin domain-containing protein 5 is preferentially expressed in a limited number of tissues, where it may function as a survival factor for nitrosative stress in vivo. It is involved in insulin production as well as in adiponectin signaling and interacts specifically with the redox-regulatory endoplasmic reticulum proteins endoplasmic oxidoreductin 1α (Ero1α) and peroxiredoxin-4. Here, we show that ERp46, although lacking a PDI-like redox-inactive b'-thioredoxin domain with its hydrophobic substrate binding site, is able to bind to a large pool of peptides containing aromatic and basic residues via all three of its catalytic domains (a(0), a and a'), though the a(0) domain may contain the primary binding site. ERp46, which shows relatively higher activity as a disulfide-reductase than as an oxidase/isomerase in vitro compared to PDI and ERp57, possesses chaperone activity in vivo, a property also shared by the C-terminal a' domain. A crystal structure of the a' domain is also presented, offering a view of possible substrate binding sites within catalytic domains of PDI proteins.
Organizational Affiliation: 
Max Planck Research Unit for Enzymology of Protein Folding, Weinbergweg 22, 06120 Halle (Saale), Germany.