PMID: 22505402

Authors:

Gulerez IE, Kozlov G, Rosenauer A, Gehring K

Title:

Structure of the third catalytic domain of the protein disulfide isomerase ERp46.

Journal:

Acta Crystallogr Sect F Struct Biol Cryst Commun. 2012 Apr 1;68(Pt 4):378-81., Epub 2012 Mar 27.

Abstract:

Protein disulfide isomerases are responsible for catalyzing the proper oxidation and isomerization of disulfide bonds of newly synthesized proteins in the endoplasmic reticulum. Here, the crystal structure of the third catalytic domain of protein disulfide isomerase ERp46 (also known as protein disulfide isomerase A5 and TXNDC5) was determined to 2.0 A resolution. The structure shows a typical thioredoxin-like fold, but also identifies regions of high structural variability. In particular, the loop between helix alpha2 and strand beta3 adopts strikingly different conformations among the five chains of the asymmetric unit. Cys381 and Cys388 form a structural disulfide and its absence in one of the molecules leads to dramatic conformational changes. The tryptophan residue Trp349 of this molecule inserts into the cavity formed by helices alpha1 and alpha3 of a neighbouring molecule, potentially mimicking the interactions of ERp46 with misfolded substrates.