ACTIVE-SITE STRUCTURE OF A HEMAGGLUTINATING PROTEASE FROM PORPHYROMONAS-GINGIVALIS - SIMILARITY TO CLOSTRIPAIN

The active site of a 44-kDa hemagglutinating arginine-specific proteas e from the putative periodontopathogen Poryhyromonas gingivalis was sp ecifically labeled with N alpha-[H-3]acetyllysine chloromethyl ketone. After enzymatic digestion of the labeled enzyme, a labeled active sit e peptide was isolated by HPLC. The sequence of the active site peptid e was determined, after its treatment with NaBH4 to reduce the ketone group of the reagent moiety, to be Asp-Val-Ala-Cys-Val-Asn-Gly. The cy steine residue was found to be the site for labeling. The sequence res embled the active site structure of the arginine-specific cysteine pro tease clostripain from Clostridium histolyticum.