9S6T
Ternary cryo-EM structure of chicken ALG12 with Dol25-PP-GlcNAc2Man7, Dol25-P-Man, and Fab
This is a non-PDB format compatible entry.
Summary for 9S6T
| Entry DOI | 10.2210/pdb9s6t/pdb |
| EMDB information | 54631 |
| Descriptor | Mannosyltransferase, Gg12-11 Fab heavy chain, Gg12-11 Fab light chain, ... (8 entities in total) |
| Functional Keywords | mannosyltransferase, ternary complex, n-linked glycosylation, transferase |
| Biological source | Gallus gallus (chicken) More |
| Total number of polymer chains | 3 |
| Total formula weight | 108756.44 |
| Authors | Alexander, J.A.N.,Chen, S.Y.,Mukherjee, S.,de Capitani, M.,Irobalieva, R.N.,Rossi, L.,Agrawal, P.,Kowal, J.,Meirelles, M.A.,Aebi, M.,Reymond, J.L.,Kossiakoff, A.A.,Riniker, S.,Locher, K.P. (deposition date: 2025-08-01, release date: 2026-03-18, Last modification date: 2026-03-25) |
| Primary citation | Alexander, J.A.N.,Chen, S.Y.,Mukherjee, S.,de Capitani, M.,Irobalieva, R.N.,Rossi, L.,Agrawal, P.,Kowal, J.,Meirelles, M.A.,Aebi, M.,Reymond, J.L.,Kossiakoff, A.A.,Riniker, S.,Locher, K.P. Structures of ALG3/9/12 reveal the assembly logic of the N-glycan oligomannose core. Nat.Chem.Biol., 2026 Cited by PubMed Abstract: Asparagine-linked glycans are essential for the maturation and function of most eukaryotic secretory proteins. The biosynthesis and transfer of dolichylpyrophosphate-anchored GlcNAcManGlc glycan is a highly conserved process occurring in the endoplasmic reticulum (ER) membrane and involving over a dozen membrane proteins whose dysfunction is linked to congenital disorders of glycosylation (CDGs). Three membrane-integral mannosyltransferases, ALG3, ALG9 and ALG12, mediate four consecutive mannosylation reactions that convert GlcNAcMan to GlcNAcMan. Here, using chemoenzymatically synthesized lipid-linked glycan donor and acceptor analogs, we recapitulated this biosynthetic pathway in vitro. High-resolution cryo-electron microscopy structures of pseudo-Michaelis complexes of each step revealed how the branched glycan is accurately synthesized and unwanted side products are averted. Molecular dynamics simulations and mutagenesis studies uncovered a subtle but precise mechanism selecting the dolichylphosphomannose donor substrate over dolichylphosphoglucose, which is also present in the ER membrane. Our results also provide mechanistic explanations for enzyme dysfunction in CDGs and offer opportunities for N-glycan engineering. PubMed: 41807832DOI: 10.1038/s41589-026-02164-7 PDB entries with the same primary citation |
| Experimental method | ELECTRON MICROSCOPY (2.42 Å) |
Structure validation
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