Purification, partial characterization and preliminary X-ray diffraction analysis of a mannose-specific lectin from Cymbosema roseum seeds

Abstract

A lectin from Cymbosema roseum seeds (CRL) was purified, characterized and crystallized. The best crystals grew in a month and were obtained by the vapour-diffusion method using a precipitant solution consisting of 0.1 M Tris-HCl pH 7.8, 8%(w/v) PEG 3350 and 0.2 M proline at a constant temperature of 293 K. A data set was collected to 1.77 A resolution at a synchrotron-radiation source. CRL crystals are orthorhombic, belonging to space group P2(1)2(1)2(1). Crystallographic refinement and full amino-acid sequence determination are in progress.

Figure 1

(a) Crystal and (b) diffraction pattern of C. roseum lectin.

Figure 2

Affinity chromatography and SDS–PAGE of the purified C. roseum lectin (CRL). (a) Sepharose-4B-mannose chromatography. (b) SDS–PAGE showing protein markers (left) and a purified CRL band (right). The molecular-weight markers are bovine serum albumin (67 kDa), chymotrypsinogen (25 kDa) and lysozyme (14 kDa). The gel was Coomassie blue stained.