Recombinant Human LARGE1 His-tag Protein, CF

Recombinant human Xylosyl- and glucuronyltransferase Like-acetylglucosaminyltransferase 1 (LARGE1) is a metal-dependent, ubiquitously-expressed, golgi single-pass type II membrane glycosyltransferase protein (1). LARGE1 is composed of a short cytoplasmic peptide, a transmembrane domain, a coiled-coil stem involved in dimerization, and two catalytic domains separated by a linker that are responsible for its bifunctional activity as a xylosyltransferase (Xyl-T domain) and glucuronyltransferase (GlcA-T domain) (1). It is thought the physiological dimeric form of LARGE1 is in parallel with homo-association of the Xyl-T and GlcA-T domains to bring catalytic domains in close proximity from opposing monomers (1). As a bifunctional glycosyltransferase, LARGE1 is responsible for addition of alternating of xylose and glucuronic acid repeating units to form the polysaccharide matriglycan, a post-translational modification unique to alpha-dystroglycan (2). Matriglycan creates binding sites for laminin G-like domains making it important for proper muscle function (1,3). Improper glycosylation of alpha dystroglycan by LARGE1 is responsible for various forms of congenital muscular dystrophy, termed dystroglycanopathies, with muscular and neurological effects as seen in Walker-Warburg syndrome (1, 4-6). In addition, LARGE1 deficiency may play a role in some types of cancer (7, 8). Pharmacological supplementation treatments of LARGE1 may be applied to treat dystroglycanopathy and cancer (8-11). The enzymatic activity of recombinant human LARGE1 was determined using a phosphate-coupled glycosyltransferase assay (12).