In this study, we used NMR (nuclear magnetic resonance) spectroscopy and the chemical shift perturbation approach to screen TCM stroke drugs for active components that are capable of binding to the second postsynaptic density 95(PSD-95)/disc large/zonula occludens-1 (PDZ) domain of PSD-95, the scaffold protein linking nNOS and PSD-95 at the postsynaptic membrane of neurons (Brenman et al.
Using NMR spectroscopy, we found that certain compounds from aqueous extracts of Huangqin, the root of Scutellaria baicalensis Georgi (Labiatae) bound to the second PDZ domain of PSD-95.
Briefly, the pET14b plasmids containing PDZ2 of PSD-95 were transformed into Escherichia coli BL21 (DE3) by electroporation.
Screening of herbs for binding activity to PDZ2 of PSD-95
The exquisite sensitivity of binding-induced chemical shift changes of PDZ2 of PSD-95 allowed us to discover PDZ-binding components in aqueous herbal extracts by simply comparing the [.
The titration curves display both dose dependent and saturable characteristics, indicative of specific interactions between the compound(s) and PDZ2 of PSD-95.