Increased sensitivity and extended range of distance measurements in spin-labeled membrane proteins: Q-band double electron-electron resonance and nanoscale bilayers.

ABSTRACT: We report a significant methodological advance in the application of double electron-electron resonance (DEER) spectroscopy to measure long-range distances in spin-labeled membrane proteins. In the pseudo two-dimensional environment of proteoliposomes, a steep intermolecular background shapes DEER signals leading to long accumulation times, complicating data analysis and reducing the maximal measurable distances from 70 A down to approximately 40-50 A. To eliminate these limitations, we took advantage of the homogeneity and monodispersity of a class of discoidal nanoscale phospholipid bilayers in conjunction with the micromolar DEER sensitivity at Q-band (34 GHz) microwave frequency. Spin-labeled mutants of the ABC transporter MsbA were functionally reconstituted at a ratio of one function

SUBMITTER: Zou P 

PROVIDER: S-EPMC2849076 | biostudies-literature | 2010 Mar

REPOSITORIES: biostudies-literature