Crystallization and preliminary crystallographic studies of the metalloglycoprotein esterase A4 using a baculovirus expression system

Esterase A4 (EA4) is a timer protein found in diapause eggs of the silkworm Bombyx mori . The gene for this metalloglycoprotein was cloned from B. mori eggs and expressed using a baculovirus expression system in silkworm pupae. Crystals of the purified protein have been grown that diffract to beyond 2.1 Å resolution at 100 K using synchrotron radiation. The protein crystals belong to space group P 2 1 , with unit‐cell parameters a = 47.1, b = 73.9, c = 47.4 Å, β = 104.1°. With one dimer per asymmetric unit, the crystal volume per unit protein weight ( V M ) is 2.3 Å 3  Da −1 and the solvent content is 47%.