Crystallization and preliminary X-ray analysis of arabinanase A from Pseudomonas fluorescens subspecies cellulosa

Crystals of 1,5-alpha-arabinanase A from Pseudomonas fluorescens subspecies cellulosa have been obtained by vapour diffusion. The crystals belong to t he space group P6(1)22 with unit-cell parameters a = b = 91.6, c = 179.4 An gstrom with one molecule in the asymmetric unit. The native crystals and, t o a much greater extent, heavy-atom soaked crystals are sensitive to radiat ion which necessitates cryocooling. Suitable cryocooling conditions have be en established, though a shrinkage of the unit cell is observed, with a = b = 88.8 and c = 176.9 Angstrom.