1rkl | pdb_00001rkl
NMR structure of yeast oligosaccharyltransferase subunit Ost4p
|
Overview
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.
About this Structure
1RKL is a Single protein structure of sequence from [1]. Active as Dolichyl-diphosphooligosaccharide--protein glycotransferase, with EC number 2.4.1.119 Full crystallographic information is available from OCA.
Reference
Structural basis for the function of a minimembrane protein subunit of yeast oligosaccharyltransferase., Zubkov S, Lennarz WJ, Mohanty S, Proc Natl Acad Sci U S A. 2004 Mar 16;101(11):3821-6. Epub 2004 Mar 4. PMID:15001703
Page seeded by OCA on Wed Nov 21 01:40:05 2007
