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Crystal structure of human GnT-V luminal domain in complex with acceptor sugar
Structural highlights
FunctionMGT5A_HUMAN Catalyzes the addition of N-acetylglucosamine in beta 1-6 linkage to the alpha-linked mannose of biantennary N-linked oligosaccharides. It is one of the most important enzymes involved in the regulation of the biosynthesis of glycoprotein oligosaccharides. Publication Abstract from PubMedN-acetylglucosaminyltransferase-V (GnT-V) alters the structure of specific N-glycans by modifying alpha1-6-linked mannose with a beta1-6-linked N-acetylglucosamine branch. beta1-6 branch formation on cell surface receptors accelerates cancer metastasis, making GnT-V a promising target for drug development. However, the molecular basis of GnT-V's catalytic mechanism and substrate specificity are not fully understood. Here, we report crystal structures of human GnT-V luminal domain with a substrate analog. GnT-V luminal domain is composed of a GT-B fold and two accessary domains. Interestingly, two aromatic rings sandwich the alpha1-6 branch of the acceptor N-glycan and restrain the global conformation, partly explaining the fine branch specificity of GnT-V. In addition, interaction of the substrate N-glycoprotein with GnT-V likely contributes to protein-selective and site-specific glycan modification. In summary, the acceptor-GnT-V complex structure suggests a catalytic mechanism, explains the previously observed inhibition of GnT-V by branching enzyme GnT-III, and provides a basis for the rational design of drugs targeting N-glycan branching. Structure and mechanism of cancer-associated N-acetylglucosaminyltransferase-V.,Nagae M, Kizuka Y, Mihara E, Kitago Y, Hanashima S, Ito Y, Takagi J, Taniguchi N, Yamaguchi Y Nat Commun. 2018 Aug 23;9(1):3380. doi: 10.1038/s41467-018-05931-w. PMID:30140003[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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