Purification and Characterization of a Novel D-Galactose Binding Lectin
from Seeds of Meizotropis buteiformis
Authors: Singh Senjam Sunil , Kamei Rana , Devi Oinam Sangita , Singh Sorokhaibam Jibankumar , Singh Wayenbam Sobhachandra 
Published: May 2022

Plant lectins are carbohydrate-binding proteins that are ubiquitously found in almost all
plant species and have different structures and functions depending on the sources. Purifying lectins from their plant sources and determining their sugar specificity become an important goal for
evaluating their potential biomedical applications. Here, we report the affinity purification of a Dgalactose specific lectin from the seeds of Meizotropis buteiformis Voigt., and its physicochemical
parameters, and LC-MS/MS (tandem mass spectrometry) analysis. Isolation and purification of this
lectin were performed by simple successive steps of lectin extraction, ammonium sulphate fractionation, and affinity chromatography using lactose-linked Sepharose-4B chromatography column. The
affinity-purified lectin has a native molecular weight of 75 kDa and is found to be a heterodimer
(molecular weight of 36 and 38 kDa). The LC-MS/MS results suggested that the purified lectin had
not been reported earlier

Aim:

The main aim of the present study is to find out the novelty and characteristics of a lectin purified from the plant Meizotropis buteiformis.

Background:

Lectins are proteins that possess the ability to specifically bind glycans of glycoconjugates. Plants are considered rich sources of lectins and the determination of sugar specificity of a
purified plant lectin is an important aspect in order to evaluate its potential area of application. In
the present study, a novel D-Galactose specific lectin is purified from Meizotropis buteiformis
through affinity chromatography and examined for its various physical and biochemical characteristics.

Objective:

The objective of the present study is to purify a novel lectin up to its homogeneity from
the seeds of Meizotropis buteiformis and characterization of its various physical and biochemical
properties.

Methods:

The lectin was purified by simple successive steps of lectin extraction, ammonium sulphate fractionation, and affinity chromatography. Activity of the purified lectin was determined by
hemagglutination assay. Some physicochemical parameters of the purified protein were also determined along with identification of protein by LC-MS/MS and the spectra analysis using Mascot
sequence matching software (Matrix Science) with the NCBI database.

Results:

From the current investigation, it was found that the purified lectin has a native molecular
weight of 75 kDa. Among the various sugars and sugar derivatives tested, lactose and D-galactose
were found to be potent inhibitors of its activity. Its optimum pH range was found to be from 6.5 to
7.5 and also it exhibited full activity at a temperature from 0ºC to 50ºC. The purified lectin does not
show any effects on its activities for metal ions tested. The protein view report of the LC-MS/MS
result analysis showed a 50% sequence similarity with that of the lectin beta-chain of the Butea
monosperma.

Conclusion:

In the present study, a novel D-Galactose specific lectin is purified from Meizotropis
buteiformis by affinity chromatography using Sepharose 4B. The purified lectin is found to be heterodimeric and metal ion independent. The LC-MS/MS results suggested that the purified lectin has
not been reported earlier