Trimethylsilyl reporter groups for NMR NMR studies of conformational changes in G protein‐coupled receptors

摘要

Large membrane proteins such as G protein‐coupled receptors ( GPCR s) are difficult for NMR study due to severe signal overlaps and unfavorable relaxation properties. We used a trimethylsilyl ( TMS ) group as a reporter group for 1 H NMR study of conformational changes in proteins, utilizing high‐intensity 1 H NMR signals near 0 p.p.m. The β 2 ‐adrenergic receptor was labeled with TMS groups at two cysteines located at the cytoplasmic ends of helices VI and VII . Binding of various ligands led to changes in 1 H NMR signals, which manifested that helix VI is sensitive to G protein‐specific activation, whereas helix VII is sensitive to β‐arrestin‐specific activation. Thus, the TMS group is a useful reporter group in NMR for studying conformational changes in membrane proteins such as GPCR s.