Unveiling the binding dynamics of banana lectin with L-fucose through integrative spectroscopic, crystallographic, and in silico studies

Banana lectin (Banlec) is a homodimeric plant lectin with glucose/mannose specificity and is also capable of recognizing other carbohydrates. The present study was conducted to evaluate the binding modalities of Banlec with L -fucose. Such structural and biophysical characterization is essential for understanding the molecular basis of Banlec–carbohydrate recognition and its potential applications in glycobiology. Banlec was purified from Musa paradisiaca , and its binding with L -fucose was analyzed via different biophysical techniques. In the first step, the binding affinity of Banlec with L-fucose was analyzed via UV–Vis spectroscopy, which revealed a decreased absorption intensity at 280 nm with increasing concentrations of L-fucose. The binding constant (K b = (4.78 ± 0.08) ×10 4 M −1 ), dissociation constant (K d =21.8 ± 0.3 µM), and Gibbs free energy (ΔG°= − 26.7 kJ mol −1 ), suggest a favourable interaction. Results of circular dichroism spectroscopic (CD) analysis showed that binding of fucose did not alter the secondary structure of Banlec. Differential scanning fluorimetry showed a slight increase in melting temperature (ΔTm = + 0.5 °C) upon L -fucose binding. Additionally, the X-ray crystal structure of Banlec–fucose complex was resolved at 2.95 Å. Two molecules of L -fucose showed binding with Ser33, Gly34, His63, His84, and Gly105 amino acid residues. Molecular docking studies further supported the experimental findings. Hence, this study provides structural insights into the carbohydrate-binding features of Banlec, particularly its interaction with L-fucose.