NMR structure of yeast oligosaccharyltransferase subunit Ost4p

Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 500 
  • Conformers Submitted: 20 
  • Selection Criteria: structures with the lowest energy 

wwPDB Validation   3D Report Full Report

This is version 1.4 of the entry. See complete history


Structural basis for the function of a minimembrane protein subunit of yeast oligosaccharyltransferase

Zubkov, S.Lennarz, W.J.Mohanty, S.

(2004) Proc Natl Acad Sci U S A 101: 3821-3826

  • DOI: https://doi.org/10.1073/pnas.0400512101
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    N-glycosylation of proteins is an essential, highly conserved modification reaction that occurs in all eukaryotes and some prokaryotes. This process is catalyzed by oligosaccharyltransferase (OT), a multisubunit enzyme localized in the endoplasmic reticulum. Complete loss of N-glycosylation is lethal in all organisms. In Saccharomyces cerevisiae, OT is composed of nine nonidentical membrane proteins. Here, we report the atomic structure of an OT subunit from S. cerevisiae, Ost4p. This unusually small membrane protein containing only 36 residues folds into a well formed, kinked helix in the model-membrane solvent system used in this study. The residues critical for the OT activity and the stability of Stt3p-Ost4p-Ost3p subcomplex are located in helix alpha2, the larger cytosolic half of this kinked helix. The residues known to disrupt Ost4p-Stt3p complex form a well defined ridge in the 3D structure. Taking together prior mutational studies and the NMR structure of Ost4p, we propose that in the OT complex Stt3p is packed against the alpha 2-helix of Ost4p by using a "ridges-into-grooves" model, with Met-18, Leu-21, and Ile-24 as the packing interface on one face, whereas Ost3p is involved in interactions with Met-19, Thr-20, Ile-22, and Val-23 on the other face.

  • Organizational Affiliation

    Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794-5215, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Dolichyl-diphosphooligosaccharide--protein glycosyltransferase 4 kDa subunit36N/AMutation(s): 0 
Membrane Entity: Yes 
Find proteins for Q99380 (Saccharomyces cerevisiae (strain ATCC 204508 / S288c))
Explore Q99380 
Go to UniProtKB:  Q99380
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ99380
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 500 
  • Conformers Submitted: 20 
  • Selection Criteria: structures with the lowest energy 

Structure Validation

View Full Validation Report

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2004-03-23
    Type: Initial release
  • Version 1.1: 2008-04-29
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2022-03-02
    Changes: Database references, Derived calculations
  • Version 1.4: 2024-05-22
    Changes: Data collection