Purification, crystallization and preliminary X-ray crystallographic analysis of recombinant murine Golgi mannosidase IA, a class I α-mannosidase involved in Asn-linked oligosaccharide maturation

Golgi mannosidase IA is a class I a-mannosidase which catalyzes the conversion of Man(9)GlcNAc(2) or Man(8)GlcNAc(2) oligosaccharide substrates to Man(5)GlcNAc(2) during the maturation of Asn-linked oligosaccharides. The enzyme is a type II membrane protein, and a recombinant form of mannosidase IA from mouse, lacking the transmembrane domain, has been expressed in Pichia pastoris, purified to homogeneity and crystallized by the hanging-drop vapor-diffusion method. The crystals grow as thin rods, with unit-cell dimensions a = 54.9, b = 135.01, c = 69.9 Angstrom. The crystals exhibit the symmetry of space group P222(1) and diffract to 2.8 Angstrom resolution. The asymmetric unit contains one monomer (similar to 53 kDa) and has a solvent content of 59%.