Gallic acid binding to Spatholobus parviflorus lectin provides insight to its quaternary structure forming

• Gallic acid (GA) binds to Spatholobus parviflorus seed lectin (SPL).
• Sugar binding site of lectin is independent of GA binding site.
• SPL-GA complex may be a model for drug delivery system.
• Structure and kinetics of SPL-GA binding unfolds the pathway of lectin quaternary structure forming.

Therapeutic effects of gallic acid (GA) have already been extensively studied. However, its interaction with lectins has not gained much attention. It is of interest to validate the binding profile of GA with Spatholobus parviflorus seed lectin. A combination of Isothermal Titration Calorimetry (ITC), haemagglutination assay and molecular docking was applied on SPL-GA interaction. ITC results showed four binding sites, stoichiometry, n = 4, irrespective of the ratio of SPL:GA taken for titration. Difference among the four binding sites of a single molecule of SPL with regard to GA binding kinetic parameters was consistently varying. Similarly, the glide scores obtained for GA in the four different binding clefts of SPL were also conformed to the ITC. The binding of GA on SPL without affecting its sugar binding property could be considered as a boon for glycobiological research. From the presented studies, it could be proposed that the SPL-GA interactions may facilitate drug delivery by specific targeting/attachment by profiling of cell-surface glycans, followed by controlled release of drugs.