Saturation transfer difference NMR on the integral trimeric membrane transport protein GltPh determines cooperative substrate binding

Saturation-transfer difference (STD) NMR spectroscopy is a fast and versatile method which can be applied for drug-screening purposes, allowing the determination of essential ligand binding affinities ( K D ). Although widely employed to study soluble proteins, its use remains negligible for membrane proteins. Here the use of STD NMR for K D determination is demonstrated for two competing substrates with very different binding affinities (low...