Internal Dynamics of the 3-Pyrroline-N-Oxide Ring in Spin-Labeled Proteins.
Philipp ConsentiusBernhard LollUlrich GohlkeClaudia AlingsCarsten MüllerRobert MüllerChristian TeutloffUdo HeinemannMartin KauppMarkus C WahlThomas RissePublished in: The journal of physical chemistry letters (2017)
Site-directed spin labeling is a versatile tool to study structure as well as dynamics of proteins using EPR spectroscopy. Methanethiosulfonate (MTS) spin labels tethered through a disulfide linkage to an engineered cysteine residue were used in a large number of studies to extract structural as well as dynamic information on the protein from the rotational dynamics of the nitroxide moiety. The ring itself was always considered to be a rigid body. In this contribution, we present a combination of high-resolution X-ray crystallography and EPR spectroscopy of spin-labeled protein single crystals demonstrating that the nitroxide ring inverts fast at ambient temperature while exhibiting nonplanar conformations at low temperature. We have used quantum chemical calculations to explore the potential energy that determines the ring dynamics as well as the impact of the geometry on the magnetic parameters probed by EPR spectroscopy.
Keyphrases
- high resolution
- single molecule
- density functional theory
- room temperature
- molecular dynamics
- living cells
- air pollution
- mass spectrometry
- amino acid
- transition metal
- healthcare
- oxidative stress
- gene expression
- health information
- human immunodeficiency virus
- ionic liquid
- tandem mass spectrometry
- climate change
- computed tomography
- small molecule
- anti inflammatory
- social media
- human health
- hepatitis c virus
- magnetic resonance