3ee5 | pdb_00003ee5
Crystal structure of human M340H-Beta1,4-Galactosyltransferase-I (M340H-B4GAL-T1) in complex with GLCNAC-Beta1,3-Gal-Beta-Naphthalenemethanol
Structural highlights
DiseaseB4GT1_HUMAN Defects in B4GALT1 are the cause of congenital disorder of glycosylation type 2D (CDG2D) [MIM:607091. CDGs are a family of severe inherited diseases caused by a defect in protein N-glycosylation. They are characterized by under-glycosylated serum proteins. These multisystem disorders present with a wide variety of clinical features, such as disorders of the nervous system development, psychomotor retardation, dysmorphic features, hypotonia, coagulation disorders, and immunodeficiency. The broad spectrum of features reflects the critical role of N-glycoproteins during embryonic development, differentiation, and maintenance of cell functions. FunctionB4GT1_HUMAN The Golgi complex form catalyzes the production of lactose in the lactating mammary gland and could also be responsible for the synthesis of complex-type N-linked oligosaccharides in many glycoproteins as well as the carbohydrate moieties of glycolipids. The cell surface form functions as a recognition molecule during a variety of cell to cell and cell to matrix interactions, as those occurring during development and egg fertilization, by binding to specific oligosaccharide ligands on opposing cells or in the extracellular matrix. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe disaccharide peracetylated GlcNAcbeta1-3Galbeta-O-naphthalenemethanol (disaccharide 1) diminishes the formation of the glycan sialyl Lewis X (Neu5Acalpha2-3Galbeta1-4(Fucalpha1-3) GlcNAc; sLe(X)) in tumor cells. Previous studies showed that the mechanism of action of disaccharide 1 involves three steps: (i) deacetylation by carboxyesterases, (ii) action as a biosynthetic intermediate for downstream enzymes involved in sLe(X) assembly, and (iii) generation of several glycans related to sLe(X). In this report, we show that GlcNAcbeta1-3Galbeta-O-naphthalenemethanol binds to the acceptor site of human beta1-4-galactosyltransferase much like the acceptor trisaccharide, GlcNAcbeta1-2Manbeta1-6Man, which is present on N-linked glycans. The 4'-deoxy analog, in which the acceptor hydroxyl group was replaced by -H, did not act as a substrate but instead acted as a competitive inhibitor of the enzyme. The acetylated form of this compound inhibited sLe(X) formation in U937 monocytic leukemia cells, suggesting that it had inhibitory activity in vivo as well. A series of synthetic acetylated analogs of 1 containing -H, -F, -N(3), -NH(2), or -OCH(3) instead of the hydroxyl groups at C-3'- and C-4'-positions of the terminal N-acetylglucosamine residue also blocked sLe(X) formation in cells. The reduction of sLe(X) by the 4'-deoxy analog also diminished experimental tumor metastasis by Lewis lung carcinoma in vivo. These data suggest that nonsubstrate disaccharides have therapeutic potential through their ability to bind to glycosyltransferases in vivo and to alter glycan-dependent pathologic processes. Deoxygenated disaccharide analogs as specific inhibitors of beta1-4-galactosyltransferase 1 and selectin-mediated tumor metastasis.,Brown JR, Yang F, Sinha A, Ramakrishnan B, Tor Y, Qasba PK, Esko JD J Biol Chem. 2009 Feb 20;284(8):4952-9. Epub 2008 Dec 23. PMID:19106107[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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