Structural highlights
Publication Abstract from PubMedUDP-glucose:glycoprotein glucosyltransferase (UGGT) flags misfolded glycoproteins for ER retention. We report crystal structures of full-length Chaetomium thermophilum UGGT (CtUGGT), two CtUGGT double-cysteine mutants, and its TRXL2 domain truncation (CtUGGT-DeltaTRXL2). CtUGGT molecular dynamics (MD) simulations capture extended conformations and reveal clamping, bending, and twisting inter-domain movements. We name "Parodi limit" the maximum distance on the same glycoprotein between a site of misfolding and an N-linked glycan that can be reglucosylated by monomeric UGGT in vitro, in response to recognition of misfold at that site. Based on the MD simulations, we estimate the Parodi limit as around 70-80 A. Frequency distributions of distances between glycoprotein residues and their closest N-linked glycosylation sites in glycoprotein crystal structures suggests relevance of the Parodi limit to UGGT activity in vivo. Our data support a "one-size-fits-all adjustable spanner" UGGT substrate recognition model, with an essential role for the UGGT TRXL2 domain. Clamping, bending, and twisting inter-domain motions in the misfold-recognizing portion of UDP-glucose:glycoprotein glucosyltransferase.,Modenutti CP, Blanco Capurro JI, Ibba R, Alonzi DS, Song MN, Vasiljevic S, Kumar A, Chandran AV, Tax G, Marti L, Hill JC, Lia A, Hensen M, Waksman T, Rushton J, Rubichi S, Santino A, Marti MA, Zitzmann N, Roversi P Structure. 2020 Dec 16. pii: S0969-2126(20)30464-0. doi:, 10.1016/j.str.2020.11.017. PMID:33352114[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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