K. Dole, F. Lipari, A. Herscovics
Oct 1, 1997
Journal of Structural Biology
Abstract The α1,2-mannosidase from Saccharomyces cerevisiae catalyzes the conversion of Man 9 GlcNAc 2 to Man 8 GlcNAc 2 during the formation of N-linked oligosaccharides and is a member of the Class 1 α1,2-mannosidases conserved from yeast to mammals. The enzyme is a type II membrane protein and a recombinant form of the α1,2-mannosidase from S. cerevisiae , lacking the transmembrane domain, has been expressed in Pichia pastoris and crystallized using the hanging drop vapor diffusion technique. The crystals grow as flat plates, with unit cell dimensions a = 57.5 A, b = 84.1 A, c = 107.1A, α = β = γ = 90°. The crystals exhibit the symmetry of space group P2 1 2 1 2 1 and diffract to a minimum d -spacing of 3.5 A resolution. On the basis of density calculations one monomer is estimated to be present in the asymmetric unit (V m = 2.08 A 3 Da − 1 ). This is the first report of the crystallization of any glycosidase involved in N -glycan biosynthesis.