Functional expression and genomic structure of human N-acetylglucosamine-6-O-sulfotransferase that transfers sulfate to β-N-acetylglucosamine at the nonreducing end of an N-acetyllactosamine sequence

Abstract

The cDNA and gene encoding human N-acetylglucosamine-6-O-sulfotransferase (Gn6ST) have been cloned. Comparative analysis of this cDNA with the mouse Gn6ST sequence indicates 96% amino acid identity between the two sequences. The expression of a soluble recombinant form of the protein in COS-1 cells produced an active sulfotransferase, which transferred sulfate to the terminal GlcNAc in GlcNAcβ1-O-CH3, GlcNAcβ1-3Galβ1-O-CH3 and GlcNAcβ1-3Galβ1-4GlcNAcβ1-3Galβ1-4GlcNAc but not in GlcNAcα1-4GlcAβ1-3Galβ1-3Galβ1-4Xylβ1-O-Ser. In addition, neither Galβ1-4GlcNAcβ1-O-naphthalenemethanol nor GalNAcβ1-4GlcAβ1-3Galβ1-3Galβ1-4Xylβ1-O-Ser were utilized as acceptors. These findings indicate that a terminal β-linked GlcNAc residue is necessary for acceptor substrates of Gn6ST. The human Gn6ST gene spans about 7 kb, consists of two exons and exhibits an intron-less coding region.