Search
Close this search box.

Cryo–electron Microscopy Structures of Human Oligosaccharyltransferase Complexes OST-A and OST-B

Author(s)

A.S. Ramírez, J. Kowal, K.P. Locher

Sources

Cryo–electron microscopy structures of human oligosaccharyltransferase complexes OST-A and OST-B Science 13 Dec 2019: Vol. 366, Issue 6471, pp. 1372-1375 DOI: 10.1126/science.aaz3505

Oligosaccharyltransferase (OST) catalyzes the transfer of a high-mannose glycan onto secretory proteins in the endoplasmic reticulum. Mammals express two distinct OST complexes that act in a cotranslational (OST-A) or post-translational (OST-B) manner. The article reports the high-resolution cryo-electron microscopy structures of human OST-A and OST-B. These structures have similar overall architectures. These structures provide insight into substrate binding of eukaryotic OST complexes and establish that the distinct functions of the two human complexes are based on structural differences of their catalytic subunits STT3A and STT3B.
capture-24.png
The authors observe an acceptor peptide and dolichol phosphate bound to STT3B, but only dolichol phosphate in STT3A, suggesting distinct affinities of the two OST complexes for protein substrates.

Latest news

DIONYSUS is a database of protein-carbohydrate interfaces annotated according to proteins and carbohydrates’ structural, chemical...

Instruct-ERIC, ”the European Research Infrastructure Consortium for Structural biology research”, is a pan-European distributed research...

Computer-based tools for visualizing and manipulating molecular structures in real-time hold immense potential for accelerating...

Glycan-mediated interactions are crucial in biology and medicine, influencing signalling, immune responses, and disease pathogenesis....