Folding of synthetic homogeneous glycoproteins in the presence of a glycoprotein folding sensor enzyme

UDP-glucose:glycoprotein glucosyltransferase (UGGT) plays a key role in recognizing folded and misfolded glycoproteins in the glycoprotein quality control system of the endoplasmic reticulum. UGGT detects misfolded glycoproteins and re-glucosylates them as a tag for misfolded glycoproteins. A flexible model to reproduce in vitro folding of a glycoprotein in the presence of UGGT in a mixture containing correctly folded, folding intermediates, and misfolded glycoproteins is described. The data demonstrates that UGGT can re-glucosylate all intermediates in the in vitro folding experiments, thus indicating that UGGT inspects not only final folded products, but also the glycoprotein folding intermediates. Folded up: A flexible model to reproduce in vitro folding of a glycoprotein in the presence of UDP-glucose:glycoprotein glucosyltransferase (UGGT) in a mixture containing correctly folded, folding intermediates, and misfolded glycoproteins is described. The data demonstrates that UGGT can re-glucosylate all intermediates, thus indicating that UGGT inspects not only final folded products, but also the glycoprotein folding intermediates.