Logo image
Structural basis of laminin binding to the LARGE glycans on dystroglycan
Journal article   Peer reviewed

Structural basis of laminin binding to the LARGE glycans on dystroglycan

David C Briggs, Takako Yoshida-Moriguchi, Tianqing Zheng, David Venzke, Mary E Anderson, Andrea Strazzulli, Marco Moracci, Liping Yu, Erhard Hohenester and Kevin P Campbell
Nature chemical biology, Vol.12(10), pp.810-814
10/2016
DOI: 10.1038/nchembio.2146
PMCID: PMC5030134
PMID: 27526028
url
http://doi.org/10.1038/nchembio.2146View
Open Access

Abstract

Dystroglycan is a highly glycosylated extracellular matrix receptor with essential functions in skeletal muscle and the nervous system. Reduced matrix binding by α-dystroglycan (α-DG) due to perturbed glycosylation is a pathological feature of several forms of muscular dystrophy. Like-acetylglucosaminyltransferase (LARGE) synthesizes the matrix-binding heteropolysaccharide [-glucuronic acid-β1,3-xylose-α1,3-]n. Using a dual exoglycosidase digestion, we confirm that this polysaccharide is present on native α-DG from skeletal muscle. The atomic details of matrix binding were revealed by a high-resolution crystal structure of laminin-G-like (LG) domains 4 and 5 (LG4 and LG5) of laminin-α2 bound to a LARGE-synthesized oligosaccharide. A single glucuronic acid-β1,3-xylose disaccharide repeat straddles a Ca(2+) ion in the LG4 domain, with oxygen atoms from both sugars replacing Ca(2+)-bound water molecules. The chelating binding mode accounts for the high affinity of this protein-carbohydrate interaction. These results reveal a previously uncharacterized mechanism of carbohydrate recognition and provide a structural framework for elucidating the mechanisms underlying muscular dystrophy.
Models, Molecular Dystroglycans - chemistry Laminin - chemistry Molecular Structure Binding Sites

Details

Metrics

Logo image