Download MendeleyToward Precise Interpretation of DEER-Based Distance Distributions: Insights from Structural Characterization of V1 Spin-Labeled Side Chains.
Balo, A.R., Feyrer, H., Ernst, O.P.(2016) Biochemistry 55: 5256-5263
- PubMed: 27532325 Search on PubMed
- DOI: https://doi.org/10.1021/acs.biochem.6b00608
- Primary Citation Related Structures:
5JGN, 5JGR, 5JGU, 5JGV, 5JGX, 5JGZ, 5KGR - PubMed Abstract:
Pulsed electron paramagnetic resonance experiments can measure individual distances between two spin-labeled side chains in proteins in the range of ∼1.5-8 nm. However, the flexibility of traditional spin-labeled side chains leads to diffuse spin density loci and thus distance distributions with relatively broad peaks, thereby complicating the interpretation of protein conformational states. Here we analyzed the spin-labeled V1 side chain, which is internally anchored and hence less flexible. Crystal structures of V1-labeled T4 lysozyme constructs carrying the V1 side chain on α-helical segments suggest that V1 side chains adopt only a few discrete rotamers. In most cases, only one rotamer is observed at a given site, explaining the frequently observed narrow distance distribution for doubly V1-labeled proteins. We used the present data to derive guidelines that may allow distance interpretation of other V1-labeled proteins for higher-precision structural modeling.
- Department of Biochemistry and ‡Department of Molecular Genetics, University of Toronto , Toronto, Ontario M5S 1A8, Canada.
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