Molecule of the Month: Oligosaccharyltransferase
Oligosaccharyltransferase adds a protective coat of carbohydrates to proteins.
Viruses and Glycans
OST-A in Action
Exploring the Structure
Active Site of Bacterial Oligosaccharyltransferase
By looking at a simpler bacterial oligosaccharyltransferase (PDB entry 5ogl), we can see the details of the carbohydrate transfer reaction. The carbohydrate is attached to the lipid through pyrophosphate, which activates the carbohydrate for the chemical reaction. The enzyme positions the acceptor asparagine close to the carbohydrate. A nearby divalent metal ion is needed for binding the molecules and catalyzing the reaction between them. To explore this structure in more detail, click on the image for an interactive JSmol.
Topics for Further Discussion
- Many glycosylated protein structures are available in the PDB archive. To find N-glycosylated proteins, use the Advanced Search and choose Structure Attribute->Glycosylation Site-> N-Glycosylation.
- To learn more about carbohydrates and how to explore them in the PDB archive, take a look at the PDB-101 page Exploring Carbohydrates in the PDB Archive.
February 2022, David Goodselldoi:10.2210/rcsb_pdb/mom_2022_2