PURIFICATION AND CHARACTERIZATION OF A LECTIN FROM SEEDS OF VATAIREA-MACROCARPA DUKE

A lectin from Vatairea macrocarpa Duke seeds (VML) was isolated using affinity chromatography on a guar gum column. The lectin, a glycoprote in without erythrocyte specificity, displays specificity to galactose and some derivatives. On SDS-polyacrylamide gels, V. macrocarpa seed l ectin is composed of two major high-Mr bands of 34 and 32 kDa and two minor low-Mr bands of 22 and 13 kDa. N-Terminal sequencing showed that the 34, 32, and 13 kDa products possess identical N-terminal sequence , which display best similarity with the N-terminal portion of Robinia pseudoacacia lectins (RPL). On the other hand, the N-terminal sequenc e of the 22 kDa band can be aligned with an internal sequence of RPL s tarting at residue 149 of the cDNA-derived sequence. These data indica te that, like ocher leguminous lectins, VML is made up of a mixture of one-chain 30-35 kDa glycoforms and of 22 and 13 kDa endogenous C- and N-terminal fragments. Size-exclusion chromatography indicated that, a t neutral pH, VML is predominantly a dimeric (70 kDa) protein, althoug h tetramers (115 kDa) and larger aggregates (300 kDa) were also presen t. (C) 1998 Elsevier Science Ltd. All rights reserved.