6kam
From Proteopedia
Crystal structure of FKRP in complex with Ba ion, CDP-ribtol, and sugar acceptor
Structural highlights
DiseaseFKRP_HUMAN Congenital muscular dystrophy with intellectual disability;Walker-Warburg syndrome;Autosomal recessive limb-girdle muscular dystrophy type 2I;Congenital muscular dystrophy with cerebellar involvement;Muscle-eye-brain disease;Congenital muscular dystrophy without intellectual disability. The disease is caused by mutations affecting the gene represented in this entry. The disease is caused by mutations affecting the gene represented in this entry. The disease is caused by mutations affecting the gene represented in this entry. FunctionFKRP_HUMAN Catalyzes the transfer of CDP-ribitol to ribitol 5-phosphate previously attached by FKTN/fukutin of to the phosphorylated O-mannosyl trisaccharide (N-acetylgalactosamine-beta-3-N-acetylglucosamine-beta-4-(phosphate-6-)mannose), a carbohydrate structure present in alpha-dystroglycan (DAG1) (PubMed:25279699, PubMed:26923585, PubMed:29477842). This constitutes the second step in the formation of the ribose 5-phosphate tandem repeat which links the phosphorylated O-mannosyl trisaccharide to the ligand binding moiety composed of repeats of 3-xylosyl-alpha-1,3-glucuronic acid-beta-1 (PubMed:25279699, PubMed:26923585, PubMed:29477842).[1] [2] [3] Publication Abstract from PubMedalpha-Dystroglycan (alpha-DG) is a highly-glycosylated surface membrane protein. Defects in the O-mannosyl glycan of alpha-DG cause dystroglycanopathy, a group of congenital muscular dystrophies. The core M3 O-mannosyl glycan contains tandem ribitol-phosphate (RboP), a characteristic feature first found in mammals. Fukutin and fukutin-related protein (FKRP), whose mutated genes underlie dystroglycanopathy, sequentially transfer RboP from cytidine diphosphate-ribitol (CDP-Rbo) to form a tandem RboP unit in the core M3 glycan. Here, we report a series of crystal structures of FKRP with and without donor (CDP-Rbo) and/or acceptor [RboP-(phospho-)core M3 peptide] substrates. FKRP has N-terminal stem and C-terminal catalytic domains, and forms a tetramer both in crystal and in solution. In the acceptor complex, the phosphate group of RboP is recognized by the catalytic domain of one subunit, and a phosphate group on O-mannose is recognized by the stem domain of another subunit. Structure-based functional studies confirmed that the dimeric structure is essential for FKRP enzymatic activity. Crystal structures of fukutin-related protein (FKRP), a ribitol-phosphate transferase related to muscular dystrophy.,Kuwabara N, Imae R, Manya H, Tanaka T, Mizuno M, Tsumoto H, Kanagawa M, Kobayashi K, Toda T, Senda T, Endo T, Kato R Nat Commun. 2020 Jan 16;11(1):303. doi: 10.1038/s41467-019-14220-z. PMID:31949166[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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