Molecular cloning and expression of a third member of the heparan sulfate/heparin GlcNAc N-deacetylase/ N-sulfotransferase family.

摘要: N-Deacetylation and N-sulfation of N-acetylglucosamine residues in heparan sulfate heparin initiate a series chemical modifications that ultimately lead to oligosaccharide sequences with specific ligand binding properties. These reactions are catalyzed by GlcNAc N-deacetylase/N-sulfotransferase (NDST), monomeric enzyme two catalytic activities. Two genes encoding NDST isozymes have been described, one from rat liver (NDST1) another murine mastocytoma (NDST2). Both expressed tissues varying amounts, but their relative contribution formation any tissue is unknown. We now report the identification third member family, designated NDST3. A full-length cDNA clone (3.2 kilobase pairs) 873-amino acid protein was obtained human fetal/infant brain library. Human NDST3 (hNDST3) has nucleotide sequence homologous not identical hNDST1 NDST2. The deduced amino shows 70% 65% identity NDST2, respectively. soluble chimera hNDST3 exhibited both N-deacetylase N-sulfotransferase activity, confirming its enzymatic identity. Northern blot analysis fetal poly(A)+ RNA showed single transcript 6.4 pairs. Reverse transcription polymerase chain reaction revealed more restricted expression than high levels brain, liver, kidney. Analysis Chinese hamster ovary cells NDST1 In cell mutant exhibiting reduced activity sulfation (Bame, K. J., Esko, J. D. (1989) Biol. Chem. 264, 8059-8065), greatly reduced, NDST2 normally, suggesting enzymes involved assembly. discovery multiple suggests assembly much complicated previously appreciated.