Internal dynamics of the 3-pyrroline-N-oxide ring in spin-labeled proteins

Item Type:	Article
Title:	Internal dynamics of the 3-pyrroline-N-oxide ring in spin-labeled proteins
Creators Name:	Consentius, P. and Loll, B. and Gohlke, U. and Alings, C. and Müller, C. and Müller, R. and Teutloff, C. and Heinemann, U. and Kaupp, M. and Wahl, M.C. and Risse, T.
Abstract:	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 of 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 being characterized by a bent conformation 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.
Keywords:	X-Ray Crystallography, Electron Spin Resonance Spectroscopy, Molecular Models, Oxides, Proteins, Pyrroles
Source:	Journal of Physical Chemistry Letters
ISSN:	1948-7185
Publisher:	American Chemical Society
Volume:	8
Number:	6
Page Range:	1113-1117
Date:	16 March 2017
Official Publication:	https://doi.org/10.1021/acs.jpclett.6b02971
PubMed:	View item in PubMed

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