EPR characterization of Mn(ii) complexes for distance determination with pulsed dipolar spectroscopy

文献情報

出版日 2016-08-16

DOI 10.1039/C6CP04884F

インパクトファクター 3.676

著者

Katharina Keller, Mian Qi, Vanessa Koch, Julia Wegner, Henrik Hintz, Adelheid Godt, Gunnar Jeschke, Anton Savitsky, Maxim Yulikov

原文を見る

要旨

The four Mn(II) complexes Mn-DOTA, Mn-TAHA, Mn-PyMTA, and Mn-NO3Py were characterized by electron paramagnetic resonance (EPR), electron–nuclear double resonance (ENDOR), and relaxation measurements, to predict their relative performance in the EPR pulse dipolar spectroscopy (PDS) experiments. High spin density localization on the metal ions was proven by ENDOR on 1H, D, 14N, and 55Mn nuclei. The transverse relaxation of the Mn(II) complexes appears to be slow enough for PDS-based spin–spin distance determination. Rather advantageous ratios of T1/Tm were measured allowing for good relaxation induced dipolar modulation enhancement (RIDME) performance and, in general, fast shot repetitions in any PDS experiment. Relaxation properties of the Mn(II) complexes correlate with the strengths of their zero field splitting (ZFS). Further, a comparison of Mn(II)-DOTA and Gd(III)-DOTA based spin labels is presented. The RIDME technique to measure nanometer-range Mn(II)–Mn(II) distances in biomolecules is discussed as an alternative to the well-known DEER technique that often appears challenging in cases of metal–metal distance measurements. The use of a modified kernel function that includes dipolar harmonic overtones allows model-free computation of the Mn(II)–Mn(II) distance distributions. Mn(II)–Mn(II) distances are computed from RIDME data of Mn-rulers consisting of two Mn-PyMTA complexes connected by a rodlike spacer of defined length. Level crossing effects seem to have only a weak influence on the distance distributions computed from this set of Mn(II)–Mn(II) RIDME data.

掲載誌

Physical Chemistry Chemical Physics

CiteScore: 5.5

自己引用率: 10.3%

年間論文数: 3036

Physical Chemistry Chemical Physics (PCCP) is an international journal co-owned by 19 physical chemistry and physics societies from around the world. This journal publishes original, cutting-edge research in physical chemistry, chemical physics and biophysical chemistry. To be suitable for publication in PCCP, articles must include significant innovation and/or insight into physical chemistry; this is the most important criterion that reviewers and Editors will judge against when evaluating submissions. The journal has a broad scope and welcomes contributions spanning experiment, theory, computation and data science. Topical coverage includes spectroscopy, dynamics, kinetics, statistical mechanics, thermodynamics, electrochemistry, catalysis, surface science, quantum mechanics, quantum computing and machine learning. Interdisciplinary research areas such as polymers and soft matter, materials, nanoscience, energy, surfaces/interfaces, and biophysical chemistry are welcomed if they demonstrate significant innovation and/or insight into physical chemistry. Joined experimental/theoretical studies are particularly appreciated when complementary and based on up-to-date approaches.