Improved 1H amide resonance line narrowing in oriented sample solid-state NMR of membrane proteins in phospholipid bilayers

► Pulse sequence to reduce 1H chemical shift line width by more than a factor of two. ► Resolution improvement for 1H-15N dipolar coupling. ► Improvements specific for membrane protein samples but not peptide single crystal. ► Applications to larger proteins, mercury transporter and G-protein coupled receptor.