Crystallization and preliminary X-ray analysis of a novel plant lectin from Calystegia sepium.

A mannose-specific lectin from Calystegia sepium has been crystallized by the hanging-drop vapour-diffusion method using ammonium sulfate as precipitant. The needle-shaped crystals are orthorhombic, space group C222(1) with cell dimensions a = 55.2(1), b = 55.9 (1), c = 196.1 (1) A. Fresh crystals diffract to 1.9 A resolution on a synchrotron radiation source. The asymmetric unit contains a dimer of two identical 16 kDa subunits with a packing density of 2.36 A(3) Da(-1). Intensity data have been observed beyond 2.0 A, but reasonable statistics restricted the usable range to 2.0 A.