6KAM image
Entry Detail
PDB ID:
6KAM
Keywords:
Title:
Crystal structure of FKRP in complex with Ba ion, CDP-ribtol, and sugar acceptor
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2019-06-23
Release Date:
2020-01-15
Method Details:
Experimental Method:
Resolution:
2.46 Å
R-Value Free:
0.24
R-Value Work:
0.20
R-Value Observed:
0.21
Space Group:
P 21 21 21
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Fukutin-related protein
Chain IDs:A, B, C, D
Chain Length:455
Number of Molecules:4
Biological Source:Homo sapiens
Primary Citation
Crystal structures of fukutin-related protein (FKRP), a ribitol-phosphate transferase related to muscular dystrophy.
Nat Commun 11 303 303 (2020)
PMID: 31949166 DOI: 10.1038/s41467-019-14220-z

Abstact

α-Dystroglycan (α-DG) is a highly-glycosylated surface membrane protein. Defects in the O-mannosyl glycan of α-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.

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Primary Citation of related structures