TY - JOUR
T1 - The structure of an archaeal oligosaccharyltransferase provides insight into the strict exclusion of proline from the N-glycosylation sequon
AU - Taguchi, Yuya
AU - Yamasaki, Takahiro
AU - Ishikawa, Marie
AU - Kawasaki, Yuki
AU - Yukimura, Ryuji
AU - Mitani, Maki
AU - Hirata, Kunio
AU - Kohda, Daisuke
N1 - Funding Information:
We thank Drs. Tadashi Suzuki and Yoichiro Harada for advice on the FNG generation assay, and Mr. Seiichiro Hayashi and Ms. Hisano Yajima for mass spectrometry of the reaction mixture for the preparation of the AfAglB-peptide complex. The DNA sequencing service was provided by the Laboratory for Research Support at the Medical Institute of Bioregulation at Kyushu University. The experiments at beamline BL44XU, SPring-8, were performed under the Cooperative Research Program of the Institute for Protein Research of Osaka University, as Proposals 20196914 and 20206514. The experiments at beamline BL32XU, SPring-8, were supported by the Platform Project for Supporting Drug Discovery and Life Science Research (Basis for Supporting Innovative Drug Discovery and Life Science Research, BINDS) from AMED under Grant Number JP19am0101070 to K.H., and by JSPS KAKENHI Grant Number JP21H02448 to D.K.
Publisher Copyright:
© 2021, The Author(s).
PY - 2021/12
Y1 - 2021/12
N2 - Oligosaccharyltransferase (OST) catalyzes oligosaccharide transfer to the Asn residue in the N-glycosylation sequon, Asn-X-Ser/Thr, where Pro is strictly excluded at position X. Considering the unique structural properties of proline, this exclusion may not be surprising, but the structural basis for the rejection of Pro residues should be explained explicitly. Here we determined the crystal structure of an archaeal OST in a complex with a sequon-containing peptide and dolichol-phosphate to a 2.7 Å resolution. The sequon part in the peptide forms two inter-chain hydrogen bonds with a conserved amino acid motif, TIXE. We confirmed the essential role of the TIXE motif and the adjacent regions by extensive alanine-scanning of the external loop 5. A Ramachandran plot revealed that the ring structure of the Pro side chain is incompatible with the ϕ backbone dihedral angle around −150° in the rigid sequon-TIXE structure. The present structure clearly provides the structural basis for the exclusion of Pro residues from the N-glycosylation sequon.
AB - Oligosaccharyltransferase (OST) catalyzes oligosaccharide transfer to the Asn residue in the N-glycosylation sequon, Asn-X-Ser/Thr, where Pro is strictly excluded at position X. Considering the unique structural properties of proline, this exclusion may not be surprising, but the structural basis for the rejection of Pro residues should be explained explicitly. Here we determined the crystal structure of an archaeal OST in a complex with a sequon-containing peptide and dolichol-phosphate to a 2.7 Å resolution. The sequon part in the peptide forms two inter-chain hydrogen bonds with a conserved amino acid motif, TIXE. We confirmed the essential role of the TIXE motif and the adjacent regions by extensive alanine-scanning of the external loop 5. A Ramachandran plot revealed that the ring structure of the Pro side chain is incompatible with the ϕ backbone dihedral angle around −150° in the rigid sequon-TIXE structure. The present structure clearly provides the structural basis for the exclusion of Pro residues from the N-glycosylation sequon.
UR - http://www.scopus.com/inward/record.url?scp=85111992864&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85111992864&partnerID=8YFLogxK
U2 - 10.1038/s42003-021-02473-8
DO - 10.1038/s42003-021-02473-8
M3 - Article
C2 - 34354228
AN - SCOPUS:85111992864
VL - 4
JO - Communications Biology
JF - Communications Biology
SN - 2399-3642
IS - 1
M1 - 941
ER -