1. Carbohydrate-Binding Mechanism of the Coagulant Lectin from Moringa oleifera Seeds (cMoL) Is Related to the Dimeric Protein Structure.
- Author
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de Barros MC, de Oliveira APS, Dos Santos FG, Silva FAC, Menezes TM, Seabra GM, Yoneda JS, Coelho LCBB, Macedo MLR, Napoleão TH, Lima TA, Neves JL, and Paiva PMG
- Subjects
- Plant Lectins chemistry, Protein Multimerization, Carbohydrates chemistry, Circular Dichroism, Lectins chemistry, Lectins metabolism, Spectrometry, Fluorescence, Protein Conformation, Thermodynamics, Hydrogen Bonding, Moringa oleifera chemistry, Seeds chemistry, Molecular Dynamics Simulation, Protein Binding
- Abstract
This study characterized the binding mechanisms of the lectin cMoL (from Moringa oleifera seeds) to carbohydrates using spectroscopy and molecular dynamics (MD). The interaction with carbohydrates was studied by evaluating lectin fluorescence emission after titration with glucose or galactose (2.0-11 mM). The Stern-Volmer constant (Ksv), binding constant (Ka), Gibbs free energy (∆G), and Hill coefficient were calculated. After the urea-induced denaturation of cMoL, evaluations were performed using fluorescence spectroscopy, circular dichroism (CD), and hemagglutinating activity (HA) evaluations. The MD simulations were performed using the Amber 20 package. The decrease in Ksv revealed that cMoL interacts with carbohydrates via a static mechanism. The cMoL bound carbohydrates spontaneously (ΔG < 0) and presented a Ka on the order of 10
2 , with high selectivity for glucose. Protein-ligand complexes were stabilized by hydrogen bonds and hydrophobic interactions. The Hill parameter (h~2) indicated that the binding occurs through the cMoL dimer. The loss of HA at urea concentrations at which the fluorescence and CD spectra indicated protein monomerization confirmed these results. The MD simulations revealed that glucose bound to the large cavity formed between the monomers. In conclusion, the biotechnological application of cMoL lectin requires specific methods or media to improve its dimeric protein structure.- Published
- 2024
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