Transverse relaxation optimized spectroscopy of NH2 groups in glutamine and asparagine side chains of proteins

Abstract

AbstractA transverse relaxation optimized spectroscopy (TROSY) approach is described for the optimal detection of NH2 groups in asparagine and glutamine side chains of proteins. Specifically, we have developed NMR experiments for isolating the slow-relaxing 15N and 1H components of NH2 multiplets. Although even modest sensitivity gains in 2D NH2-TROSY correlation maps compared to their decoupled NH2–HSQC counterparts can be achieved only occasionally, substantial improvements in resolution of the NMR spectra are demonstrated for asparagine and glutamine NH2 sites of a buried cavity mutant, L99A, of T4 lysozyme at 5 ºC. The NH2-TROSY approach is applied to CPMG relaxation dispersion measurements at the side chain NH2 positions of the L99A T4 lysozyme mutant — a model system for studies of the role of protein dynamics in ligand binding.