Interactions and Dissociation Constants of Galactomannan Rendered Cellulose Films with Concavalin A by SPR Spectroscopy

Publication year: 2020
Authors: Vilaró P. 1,†, Sampl C. 2,†,Teichert G. 2, Schlemmer W. 2, Hobisch M. 2, Weissl M. 2, Panizzolo L. 3, Ferreira F. 1, Spirk S. 2,*
1 - Sede Tacuarembó, Espacio de Ciencia y Tecnología Química, Universidad de la República, CENUR Nores-te. Ruta 5 Km 386, Tacuarembó 45000, Uruguay
2 - Institute of Bioproducts and Paper Technology, Graz University of Technology, Inffeldgasse 23, 8010 Graz, Austria
3 - Departamento de Ciencia y Tecnología de Alimentos, Facultad de Química, Universidad de la República, Avenida General Flores 2124, Montevideo 11800, Uruguay
* Author to whom correspondence should be addressed
† Contributed equally
Published in: Polymers, 2020, Vol. 12(12), p.3040
doi: 10.3390/polym12123040

Interactions of biomolecules at interfaces are important for a variety of physiological processes. Among these, interactions of lectins with monosaccharides have been investigated extensively in the past, while polysaccharide-lectin interactions have scarcely been investigated. Here, we explore the adsorption of galactomannans (GM) extracted from Prosopis affinis on cellulose thin films determined by a combination of multi-parameter surface plasmon resonance spectroscopy (MP-SPR) and atomic force microscopy (AFM). The galactomannan adsorbs spontaneously on the cellulose surfaces forming monolayer type coverage (0.60 ± 0.20 mg·m−2). The interaction of a lectin, Concavalin A (ConA), with these GM rendered cellulose surfaces using MP-SPR has been investigated and the dissociation constant KD (2.1 ± 0.8 × 10−8 M) was determined in a range from 3.4 to 27.3 nM. The experiments revealed that the galactose side chains as well as the mannose reducing end of the GM are weakly interacting with the active sites of the lectins, whereas these interactions are potentially amplified by hydrophobic effects between the non-ionic GM and the lectins, thereby leading to an irreversible adsorption.

MP-SPR keywords: adsorption, Au sensor slide, protein-oligosaccharide interaction