Crystal structure of the C-terminal globular domain of oligosaccharyltransferase (AF_0329) from Archaeoglobus fulgidusCrystal structure of the C-terminal globular domain of oligosaccharyltransferase (AF_0329) from Archaeoglobus fulgidus

Structural highlights

3vgp is a 1 chain structure with sequence from Archaeoglobus fulgidus DSM 4304. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 1.75Å
Ligands:
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

AGLB1_ARCFU Oligosaccharyl transferase (OST) that catalyzes the initial transfer of a defined glycan (a GalNAc-linked heptasaccharide composed of 4 Hex, 3 dHex and a sulfate for A.fulgidus AglB-S) from the lipid carrier dolichol-monophosphate to an asparagine residue within an Asn-X-Ser/Thr consensus motif in nascent polypeptide chains, the first step in protein N-glycosylation.[1]

Publication Abstract from PubMed

Protein N-glycosylation occurs in the three domains of life. Oligosaccharyltransferase (OST) transfers glycan to asparagine in the N-glycosylation sequon. The catalytic subunit of OST is called STT3 in eukaryotes, AglB in archaea, and PglB in eubacteria. The genome of a hyperthermophilic archaeon, Archaeoglobus fulgidus, encodes three AglB paralogs. Two of them are the shortest AglBs across all domains of life. We determined the crystal structure of the C-terminal globular domain of the smallest AglB to identify the minimal structural unit. The Archaeoglobus AglB lacked a beta-barrel-like structure, which had been found in other AglB and PglB structures. In agreement, the deletion in a larger Pyrococcus AglB confirmed its dispensability for the activity. By contrast, the Archaeoglobus AglB contains a kinked helix bearing a conserved motif, called DK/MI motif. The lysine and isoleucine residues in the motif participate in the Ser/Thr recognition in the sequon. The Archaeoglobus AglB structure revealed that the kinked helix contained an unexpected insertion. A revised sequence alignment based on this finding identified a variant type of the DK motif with the insertion. A mutagenesis study of the Archaeoglobus AglB confirmed the contribution of this particular type of the DK motif to the activity. When taken together with our previous results, this study defined the classification of OST: one group consisting of eukaryotes and most archaea possesses the DK-type Ser/Thr pocket, and the other group consisting of eubacteria and the remaining archaea possesses the MI-type Ser/Thr pocket. This classification provides a useful framework for OST studies.

Crystal Structure of the C-Terminal Globular Domain of Oligosaccharyltransferase from Archaeoglobus fulgidus at 1.75 A Resolution.,Matsumoto S, Igura M, Nyirenda J, Matsumoto M, Yuzawa S, Noda N, Inagaki F, Kohda D Biochemistry. 2012 May 22;51(20):4157-66. Epub 2012 May 14. PMID:22559858[2]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

  1. Taguchi Y, Fujinami D, Kohda D. Comparative Analysis of Archaeal Lipid-linked Oligosaccharides That Serve as Oligosaccharide Donors for Asn Glycosylation. J Biol Chem. 2016 May 20;291(21):11042-54. PMID:27015803 doi:10.1074/jbc.M115.713156
  2. Matsumoto S, Igura M, Nyirenda J, Matsumoto M, Yuzawa S, Noda N, Inagaki F, Kohda D. Crystal Structure of the C-Terminal Globular Domain of Oligosaccharyltransferase from Archaeoglobus fulgidus at 1.75 A Resolution. Biochemistry. 2012 May 22;51(20):4157-66. Epub 2012 May 14. PMID:22559858 doi:10.1021/bi300076u

3vgp, resolution 1.75Å

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