Purification and characterization of a mannose/N-acetyl-D-glucosamine-specific lectin from the seeds of Platymiscium floribundum Vogel

Platymiscium floribundum lectin (PFL), a mannose/N-acetyl- d-glucosamine-specific lectin, was isolated from P. floribundum seeds using Sepharosemannose affinity media chromatography. PFL is a glycoprotein that is a potent agglutinin for rabbit erythrocytes. In addition, PFL is highly stable because it is able to maintain its hemagglutinating activity after exposure to temperatures of up to 60?degrees C for 1 h and exposure to a wide pH range. The PFL purification process was monitored using sodium dodecyl sulfatepolyacrylamide gel electrophoresis, and the results showed that the purified lectin consists of a single band with a molecular mass of approximately 29?kDa in either the presence or the absence of a reducing agent. The analysis of purified PFL by electrospray ionizationmass spectrometry showed that most ions had a molecular weight of 27,053?+/-?2?Da, and other less abundant ions had similar molecular weights. Gel filtration shows that the lectin exists as a dimer in solution with mass at approximately 65?kDa. Sixteen peptides were sequenced, and as a result, a total of 130 amino acids were identified and resulted in a coverage of approximately 65% of the PFL sequence. The partial sequence of PFL was aligned with sequences of other lectins from evolutionarily related species, and PFL showed considerable similarity to the other lectins. Copyright (c) 2012 John Wiley & Sons, Ltd.