Crystallization and preliminary x-ray diffraction analysis of cold-active beta-galactosidase from arthrobacter SP.C2-2

摘要

beta-Galactosidase from psychrotrophic bacteria strain Arthrobacter sp.C2-2 catalyzes cleavage of beta-D-galactosyl moieties from beta-D-galactosides and is interesting for its activity at low temperatures.Various types of crystals with dimensions of up to 0.8 mm were obtained and X-ray diffraction data up to 1.9 A were collected.The crystals belong to the monoclinic space group P2_1 with unit-cell parameters a = 140.1 A,b = 205.7 A,c = 140.5 A and beta = 102.3deg.The enzyme (molecular weight of a monomer is 111 kDa) forms hexamers in the crystal structure (one hexamer per asymmetric unit).The phase problem was solved by molecular replacement.Structure refinement is in progress.