Gadolinium(III) Spin Labels for High‐Sensitivity Distance Measurements in Transmembrane Helices

Abstract

High-frequency double electron-electron resonance (DEER) distance measurements using different Gd3+ tags (Gd-DOTA and Gd-C1) were carried out on transmembrane helical peptides (ca. 0.15 nmol; WALP peptides) in a model membrane. The ability to pick up small distance variations, the chemical flexibility of the tags, and the remarkable absolute sensitivity, make this approach attractive for studies of membrane proteins.