Isolation of a lectin and a galactoxyloglucan from Mucuna sloanei seeds

• Published in: Phytochemistry (Oxford) 2009-12, Vol.70 (17), p.1965-1972
• Main Authors: Teixeira-Sá, Daniele M.A., Reicher, Fany, Braga, Renata C., Beltramini, Leila Maria, de Azevedo Moreira, Renato
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Biological and medical sciences; carbohydrate structure; Carbohydrates; Chemical constitution; Chromatography, Affinity; Circular Dichroism; cotyledons; Electrophoresis, Polyacrylamide Gel; Erythrocytes - drug effects; Fabaceae; Fundamental and applied biological sciences. Psychology; galactose; Galactoxyloglucan; glucans; Glucans - chemistry; Glucans - isolation & purification; Glucans - metabolism; glycosidic linkages; hemagglutination tests; Hemagglutinins - chemistry; Hemagglutinins - isolation & purification; Hemagglutinins - pharmacology; Humans; Lectin; lectins; Mannans; methylation; Molecular Structure; Mucuna - chemistry; Mucuna sloanei; nuclear magnetic resonance spectroscopy; Plant Lectins - chemistry; Plant Lectins - isolation & purification; Plant Lectins - metabolism; Plant Lectins - pharmacology; Plant physiology and development; polysaccharides; Rabbits; seeds; Seeds - chemistry; Sequence Homology; Sloanin
• ISSN: 0031-9422; 1873-3700
• DOI: 10.1016/j.phytochem.2009.08.011

Mucuna sloanei Fawcett and Rendle is a member of the Leguminosae ( Fabaceae) found in northeast Brazil. In this paper, a lectin and a galactoxyloglucan from seeds were detected, isolated, and characterized; interactions studies were also carried out. A lectin and a galactoxyloglucan were characterized from Mucuna sloanei seed cotyledons. The galactoxyloglucan, isolated by water extraction and ethanol precipitation, had Glc:Xyl:Gal proportions in a molar ratio of 1.8:1.7:1.0 and a molar mass ( M w) of 1.6 × 10 6 g mol −1. The lectin (sloanin), isolated from the same seed by affinity chromatography on cross-linked Adenanthera pavonina galactomannan, gave two protein bands by SDS–PAGE (36 and 34 kDa) and one peak by gel filtration (63.6 kDa). Its N-terminal sequence indicated ∼69% identity with soybean agglutinin to leguminous lectins. Circular dichroism (CD) spectra established that sloanin predominantly contains β-sheet structures. Sloanin has ∼5.5% carbohydrate and displayed hemagglutinating activity against rabbit and enzyme treated human erythrocytes, inhibited only by d-Gal containing sugars. The interaction between sloanin and storage cell-wall galactoxyloglucan was tested by affinity chromatography and fluorescence spectroscopy.