Chondroitin 4-sulphotransferase-1 and chondroitin 6-sulphotransferase-1 are affected differently by uronic acid residues neighbouring the acceptor GalNAc residues.
C4ST-1 (chondroitin 4-sulphotransferase-1) and C6ST-1 (chondroitin 6-sulphotransferase-1) transfer sulphate from PAPS (adenosine 3'-phosphate 5'-phosphosulphate) to positions 4 and 6 respectively of the GalNAc residues of chondroitin. We showed previously that C4ST-1 purified from rat chondrosarcoma and recombinant C4ST-1 both transfer sulphate efficiently to position 4 of the GalNAc residues of DSDS (desulphated dermatan sulphate). We report here the specificity of C4ST-1 and C6ST-1 in terms of uronic acid residue recognition around the GalNAc residue to which sulphate is transferred. When [35S]glycosaminoglycans formed from DSDS after incubation with [35S]PAPS and C4ST-1 were digested with chondroitinase ACII, a major part of the radioactivity was recovered in disaccharide fractions and the remainder distributed to tetrasaccharides and larger fractions, indicating that C4ST-1 mainly transferred sulphate to position 4 of the GalNAc residue located at the GlcA-GalNAc-GlcA sequence. Structural analysis of tetrasaccharide and larger oligosaccharide fractions indicated that C4ST-1 mainly transferred sulphate to the GalNAc residue adjacent to the reducing side of the GlcA residue. On the other hand, when [35S]glycosaminoglycans formed from DSDS after incubation with [35S]PAPS and C6ST-1 were digested with chondroitinase ACII, a major part of the radioactivity was recovered in fractions larger than hexasaccharides, indicating that C6ST-1 transferred sulphate to the GalNAc residues located in the L-iduronic acid-rich region. Structural analysis of the tetrasaccharide and larger oligosaccharide fractions indicated that C6ST-1 showed very little preference for the GalNAc residue neighbouring the GlcA residue. These results indicate that C4ST-1 and C6ST-1 differ from each other in the recognition of uronic acid residues adjacent to the targeted GalNAc residue.
Department of Chemistry, Aichi University of Education, Igaya-cho, Kariya, Aichi 448-8542, Japan.
Takayoshi
T
Yamada
Shiori
S
Ohtake
Makoto
M
Sato
Osami
O
Habuchi
D000116:Acetylgalactosamine / Q000378:metabolism*; D002240:Carbohydrate Sequence; D002810:Chondroitinases and Chondroitin Lyases / Q000378:metabolism; D004187:Disaccharides / Q000378:metabolism; D006025:Glycosaminoglycans / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D008628:Mercury / Q000494:pharmacology; D008969:Molecular Sequence Data; D013379:Substrate Specificity; D013431:Sulfates / Q000378:metabolism; D015238:Sulfotransferases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D014574:Uronic Acids / Q000378:metabolism*; D000097811:Carbohydrate Sulfotransferases
D000116:Acetylgalactosamine; D002810:Chondroitinases and Chondroitin Lyases; D004187:Disaccharides; D006025:Glycosaminoglycans; D008628:Mercury; D013431:Sulfates; D015238:Sulfotransferases; D014574:Uronic Acids; D000097811:Carbohydrate Sulfotransferases; C019893:chondroitin 4-sulfotransferase; C029823:mercuric acetate