Substrate specificities of mouse heparan sulphate glucosaminyl 6-O-sulphotransferases.
Glycosaminoglycan heparan sulphate interacts with a variety of proteins, such as growth factors, cytokines, enzymes and inhibitors and, thus, influences cellular functions, including adhesion, motility, differentiation and morphogenesis. The interactions generally involve saccharide domains in heparan sulphate chains, with precisely located O-sulphate groups. The 6-O-sulphate groups on glucosamine units, supposed to be involved in various interactions of functional importance, occur in different structural contexts. Three isoforms of the glucosaminyl 6-O-sulphotransferase (6-OST) have been cloned and characterized [H. Habuchi, M. Tanaka, O. Habuchi, K. Yoshida, H. Suzuki, K. Ban and K. Kimata (2000) J. Biol. Chem. 275, 2859-2868]. We have studied the substrate specificities of the recombinant enzymes using various O-desulphated poly- and oligo-saccharides as substrates, and using adenosine 3'-phosphate 5'-phospho[(35)S]sulphate as sulphate donor. All three enzymes catalyse 6-O-sulphation of both -GlcA-GlcNS- and -IdoA-GlcNS- (where GlcA represents D-glucuronic acid, NS the N-sulphate group and IdoA the L-iduronic acid) sequences, with preference for IdoA-containing targets, with or without 2-O-sulphate substituents. 6-OST1 showed relatively higher activity towards target sequences lacking 2-O-sulphate, e.g. the -GlcA-GlcNS- disaccharide unit. Sulphation of such non-O-sulphated acceptor sequences was generally favoured at low acceptor polysaccharide concentrations. Experiments using partially O-desulphated antithrombin-binding oligosaccharide as the acceptor revealed 6-O-sulphation of N-acetylated as well as 3-O-sulphated glucosamine residues with each of the three 6-OSTs. We conclude that the three 6-OSTs have qualitatively similar substrate specificities, with minor differences in target preference.
Smeds
Emanuel
E
Institute of Molecular Science of Medicine, Aichi Medical University, Nagakute, Japan.
Habuchi
Hiroko
H
Do
Anh-Tri
AT
Hjertson
Eva
E
Grundberg
Helena
H
Kimata
Koji
K
Lindahl
Ulf
U
Kusche-Gullberg
Marion
M
D000818:Animals; D019556:COS Cells / Q000201:enzymology; D002240:Carbohydrate Sequence; D002417:Cattle; D002522:Chlorocebus aethiops; D002851:Chromatography, High Pressure Liquid; D005944:Glucosamine / Q000378:metabolism*; D019812:Heparan Sulfate Proteoglycans / Q000378:metabolism*; D007413:Intestinal Mucosa / Q000378:metabolism; D008168:Lung / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000737:chemistry / Q000378:metabolism; D020033:Protein Isoforms; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D013379:Substrate Specificity; D015238:Sulfotransferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013552:Swine
D019812:Heparan Sulfate Proteoglycans; D009844:Oligosaccharides; D020033:Protein Isoforms; D011993:Recombinant Fusion Proteins; C485756:Hs6st1 protein, mouse; C485758:Hs6st2 protein, mouse; C485759:Hs6st3 protein, mouse; D015238:Sulfotransferases; C404189:heparan sulfate 6-O-sulfotransferase; D005944:Glucosamine