Identification and removal of nitroxide spin label contaminant: impact on PRE studies of α-helical membrane proteins in detergent.

ABSTRACT: NMR paramagnetic relaxation enhancement (PRE) provides long-range distance constraints (~15-25 Å) that can be critical to determining overall protein topology, especially where long-range NOE information is unavailable such as in the case of larger proteins that require deuteration. However, several challenges currently limit the use of NMR PRE for α-helical membrane proteins. One challenge is the nonspecific association of the nitroxide spin label to the protein-detergent complex that can result in spurious PRE derived distance restraints. The effect of the nitroxide spin label contaminant is evaluated and quantified and a robust method for the removal of the contaminant is provided to advance the application of PRE restraints to membrane protein NMR structure determination.

SUBMITTER: Kroncke BM 

PROVIDER: S-EPMC3375759 | biostudies-literature | 2012 Apr

REPOSITORIES: biostudies-literature