STRUCTURAL-ANALYSIS OF N-LINKED CARBOHYDRATE CHAINS OF FUNNEL-WEB SPIDER (AGELENOPSIS-APERTA) VENOM PEPTIDE ISOMERASE

The structure of the N-linked carbohydrate chains of peptide isomerase from the venom of the funnel web spider (Agelenopsis aperta) has been analyzed. Carbohydrates were released from peptide isomerase by hydra zinolysis and reductively aminated with 2-aminopyridine. The fluoresce nt derivatives were purified by phenol/chloroform extraction, followed by size-exclusion HPLC. The structure of the purified pyridylamino (P A-) carbohydrate chains were analyzed by a combination of two-dimensio nal HPLC mapping, sugar composition analysis, sequential exoglycosidas e digestions, and mass spectrometry. The peptide isomerase contains si x kinds of N-linked carbohydrate chains of truncated high-mannose type , with a fucose alpha 1-6 linked to the reducing N-acetylglucosamine i n approximately 80% of them.