CRYSTAL-STRUCTURE OF GLYCOSYLASPARAGINASE FROM FLAVOBACTERIUM-MENINGOSEPTICUM

The crystal structure of recombinant glycosylasparaginase from Flavoba cterium meningosepticum has been determined at 2.32 Angstrom resolutio n. This enzyme is a glycoamidase that cleaves the link between the asp aragine and the N-acetylglucosamine of N-linked oligosaccharides and p lays a major role in the degradation of glycoproteins. The three-dimen sional structure of the bacterial enzyme is very similar to that of th e human enzyme, although it lacks the four disulfide bridges found in the human enzyme. The main difference is the absence of a small random coil domain at the end of the alpha-chain that forms part of the subs trate binding cleft and that has a role in the stabilization of the te tramer of the human enzyme. The bacterial glycosylasparaginase is obse rved as an (alpha beta)(2)-tetramer in the crystal, despite being a di mer in solution. The study of the structure of the bacterial enzyme al lows further evaluation of the effects of disease-causing mutations in the human enzyme and confirms the suitability of the bacterial enzyme as a model for functional analysis.