Frequency-selective heteronuclear dephasing and selective carbonyl labeling to deconvolute crowded spectra of membrane proteins by magic angle spinning NMR

► Carbonyl-selective labeling in combination with frequency-selective heteronuclear recoupling for assignments of crowded membrane protein spectra. ► The method discriminates overlapped 13Cα resonances by strategically labeling the preceding residue. ► This approach is complementary to 13Ci-1′-15Ni-13Ciα and 13Ci-1α-15Ni-1-13Ci′ experiments at a minimal cost to signal-to-noise.