Binding properties of marine bromophenols with human protein tyrosine phosphatase 1B: Molecular docking, surface plasmon resonance and cellular insulin resistance study.

Protein tyrosine phosphatase 1B (PTP1B) is a highly validated target for the treatment of type 2 diabetes and obesity. Previous studies have shown that bromophenols from marine red alga Rhodomela confervoides can inhibit PTP1B activity. However, traditional in vitro enzymatic assays may result in false positive activity. Here, we reported a successful application of molecular docking and surface plasmon resonance (SPR) assay for the characterization of small-molecule PTP1B inhibitors with high affinity. First, molecular docking study indicated that six bromophenol compounds preferred to bind PTP1B with open conformation rather than one with closed conformation. Next, SPR study indicated that compound 3 was the most potent and stable PTP1B inhibitor at the nanomolar level. Then Lineweaver-Burk plot data showed that compound 3 was a competitive PTP1B inhibitor. Moreover, compound 3 could improve palmitate-induced insulin resistance in HepG2 cells. Taken together, molecular docking and SPR-based methodology could apply in the development of PTP1B inhibitors with high affinity.