Crystallization and preliminary X-ray diffraction analysis of the fructofuranosidase from Schwanniomyces occidentalis

Schwanniomyces occidentalis invertase is an extracellular enzyme that releases beta-fructose from the nonreducing termini of various beta-D-fructofuranoside substrates. Its ability to produce 6-kestose by transglycosylation makes this enzyme an interesting research target for applications in industrial biotechnology. The enzyme has been expressed in Saccharomyces cerevisiae. Recombinant and wildtype forms, which showed different glycosylation patterns, were crystallized by vapour-diffusion methods. Although crystallization trials were conducted on both forms of the protein, crystals suitable for X-ray crystallographic analyses were only obtained from the wild-type enzyme. The crystals belonged to space group P2(1)2(1)2(1), with unit-cell parameters a = 105.78, b = 119.49, c = 137.68 angstrom. A diffraction data set was collected using a synchrotron source. Self-rotation function and sedimentation-velocity experiments suggested that the enzyme was dimeric with twofold symmetry.