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7vmt

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Crystal structure of murine N-acetylglucosaminyl transferase IVa (GnT-IVa) lectin domain in unliganded form

Structural highlights

7vmt is a 6 chain structure with sequence from Mus musculus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 1.9500064Å
Ligands:
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

MGT4A_MOUSE Glycosyltransferase that catalyze the transfer of GlcNAc from UDP-GlcNAc to the GlcNAcbeta1-2Manalpha1-3 arm of the core structure of N-linked glycans through a beta1-4 linkage and participates in the production of tri- and tetra-antennary N-linked sugar chains (PubMed:16377570). Involved in glucose transport by mediating SLC2A2/GLUT2 glycosylation, thereby controlling cell-surface expression of SLC2A2 in pancreatic beta cells (PubMed:16377570).^[1]

Publication Abstract from PubMed

N-Glycosylation is a common post-translational modification, and the number of GlcNAc branches in N-glycans impacts glycoprotein functions. N-Acetylglucosaminyltransferase-IVa (GnT-IVa, also designated as MGAT4A) forms a beta1-4 GlcNAc branch on the alpha1-3 mannose arm in N-glycans. Downregulation or loss of GnT-IVa causes diabetic phenotypes by dysregulating glucose transporter-2 in pancreatic beta-cells. Despite the physiological importance of GnT-IVa, its structure and catalytic mechanism are poorly understood. Here, we identify the lectin domain in mouse GnT-IVa's C-terminal region. The crystal structure of the lectin domain shows structural similarity to a bacterial GlcNAc-binding lectin. Comprehensive glycan binding assay using 157 glycans and solution NMR reveal that the GnT-IVa lectin domain selectively interacts with the product N-glycans having a beta1-4 GlcNAc branch. Point mutation of the residue critical to sugar recognition impairs the enzymatic activity, suggesting that the lectin domain is a regulatory subunit for efficient catalytic reaction. Our findings provide insights into how branching structures of N-glycans are biosynthesized.

Discovery of a lectin domain that regulates enzyme activity in mouse N-acetylglucosaminyltransferase-IVa (MGAT4A).,Nagae M, Hirata T, Tateno H, Mishra SK, Manabe N, Osada N, Tokoro Y, Yamaguchi Y, Doerksen RJ, Shimizu T, Kizuka Y Commun Biol. 2022 Jul 19;5(1):695. doi: 10.1038/s42003-022-03661-w. PMID:35854001^[2]

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

References

↑ Ohtsubo K, Takamatsu S, Minowa MT, Yoshida A, Takeuchi M, Marth JD. Dietary and genetic control of glucose transporter 2 glycosylation promotes insulin secretion in suppressing diabetes. Cell. 2005 Dec 29;123(7):1307-21. doi: 10.1016/j.cell.2005.09.041. PMID:16377570 doi:http://dx.doi.org/10.1016/j.cell.2005.09.041
↑ Nagae M, Hirata T, Tateno H, Mishra SK, Manabe N, Osada N, Tokoro Y, Yamaguchi Y, Doerksen RJ, Shimizu T, Kizuka Y. Discovery of a lectin domain that regulates enzyme activity in mouse N-acetylglucosaminyltransferase-IVa (MGAT4A). Commun Biol. 2022 Jul 19;5(1):695. doi: 10.1038/s42003-022-03661-w. PMID:35854001 doi:http://dx.doi.org/10.1038/s42003-022-03661-w