Crystallization and preliminary X-ray studies of sialidase L from the leech Macrobdella decora

Functional monomeric 83 kDa sialidase L, a NeuAcalpha2-->3Gal-specific sialidase from Macrobdella leech, was expressed in Escherichia coli and readily crystallized by a macroseeding technique. The crystal belongs to space group P1 with unit-cell parameters a = 46.4, b = 69.3, c = 72.5 A, alpha = 113.5, beta = 95.4 and gamma = 107.3 degrees. There is one molecule per unit cell, giving a Vm = 2.4 A3 Da-1 and a solvent content of 40%. Native and mercury-derivative data sets were collected to 2.0 A resolution. Threading and molecular-replacement calculations confirmed the existence of a bacterial sialidase-like domain.