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Suzuki K, Kaji H. Torsion Angle Analysis of a Thermally Activated Delayed Fluorescence Emitter in an Amorphous State Using Dynamic Nuclear Polarization Enhanced Solid-State NMR. J Am Chem Soc 2023. [PMID: 37487017 DOI: 10.1021/jacs.3c05204] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/26/2023]
Abstract
The torsion angle between donor and acceptor segments of a thermally activated delayed fluorescence (TADF) molecule is one of the most critical factors in determining the performance of TADF-based organic light-emitting diodes (OLEDs) because the torsion angle affects not only the energy gap between the singlet and triplet but also the oscillator strength and spin-orbit coupling. However, the torsion angle is difficult to analyze, because organic molecules are in an amorphous state in OLEDs. Here, we determined the torsion angle of a highly efficient TADF emitter, DACT-II, in an amorphous state by dynamic nuclear polarization enhanced solid-state NMR measurements. From the experimentally obtained chemical shift principal values of 15N on carbazole, we determined the average torsion angle to be 52°. Such quantification of the torsion angles in TADF molecules in amorphous solids will provide deep insight into the TADF mechanism in amorphous OLEDs.
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Affiliation(s)
- Katsuaki Suzuki
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Hironori Kaji
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
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2
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Anderson JS, Hernández G, LeMaster DM. 13C NMR Relaxation Analysis of Protein GB3 for the Assessment of Side Chain Dynamics Predictions by Current AMBER and CHARMM Force Fields. J Chem Theory Comput 2020; 16:2896-2913. [PMID: 32268062 DOI: 10.1021/acs.jctc.0c00050] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Molecular simulations with seven current AMBER- and CHARMM-based force fields yield markedly differing internal bond vector autocorrelation function predictions for many of the 223 methine and methylene H-C bonds of the 56-residue protein GB3. To enable quantification of accuracy, 13C R1, R2, and heteronuclear NOE relaxation rates have been determined for the methine and stereochemically assigned methylene Cα and Cβ positions. With only three experimental relaxation values for each bond vector, central to this analysis is the accuracy with which MD-derived autocorrelation curves can be represented by a 3-parameter equation which, in turn, maps onto the NMR relaxation values. In contrast to the more widely used extended Lipari-Szabo order parameter representation, 95% of these MD-derived internal autocorrelation curves for GB3 can be fitted to within 1.0% rmsd over the time frame from 30 ps to 4 ns by a biexponential Larmor frequency-selective representation (LF-S2). Applying the LF-S2 representation to the experimental relaxation rates and uncertainties serves to determine the boundary range for the autocorrelation function of each bond vector consistent with the experimental data. Not surprisingly, all seven force fields predict the autocorrelation functions for the more motionally restricted 1Hα-13Cα and 1Hβ-13Cβ bond vectors with reasonable accuracy. However, for the 1Hβ-13Cβ bond vectors exhibiting aggregate order parameter S2 values less than 0.85, only 1% of the MD-derived predictions lie with 1 σ of the experimentally determined autocorrelation functions and only 7% within 2 σ. On the other hand, substantial residue type-specific improvements in predictive performance were observed among the recent AMBER force fields. This analysis indicates considerable potential for the use of 13C relaxation measurements in guiding the optimization of the side chain dynamics characteristics of protein molecular simulations.
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Affiliation(s)
- Janet S Anderson
- Department of Chemistry, Union College, Schenectady, New York 12308, United States
| | - Griselda Hernández
- Wadsworth Center, New York State Department of Health, Empire State Plaza, Albany, New York 12201, United States
| | - David M LeMaster
- Wadsworth Center, New York State Department of Health, Empire State Plaza, Albany, New York 12201, United States
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3
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Goldbourt A. Structural characterization of bacteriophage viruses by NMR. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2019; 114-115:192-210. [PMID: 31779880 DOI: 10.1016/j.pnmrs.2019.06.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 06/03/2019] [Accepted: 06/26/2019] [Indexed: 06/10/2023]
Abstract
Magic-angle spinning (MAS) solid-state NMR has provided structural insights into various bacteriophage systems including filamentous, spherical, and tailed bacteriophage viruses. A variety of methodologies have been utilized including elementary two and three-dimensional assignment experiments, proton-detection techniques at fast spinning speeds, non-uniform sampling, structure determination protocols, conformational dynamics revealed by recoupling of anisotropic interactions, and enhancement by dynamic nuclear polarization. This review summarizes most of the studies performed during the last decade by MAS techniques and makes comparisons with prior knowledge obtained from static and solution NMR techniques. Chemical shifts for the capsids of the various systems are reported and analyzed, and DNA shifts are reported and discussed in the context of general high molecular-weight DNA molecules. Chemical shift and torsion angle prediction techniques are compared and applied to the various phage systems. The structures of the intact M13 filamentous bacteriophage and that of the Acinetobacter phage AP205 capsid, determined using MAS-based experimental data, are presented. Finally, filamentous phages, which are highly rigid systems, show interesting dynamics at the interface of the capsid and DNA, and their mutual electrostatic interactions are shown to be mediated by highly mobile positively charged residues. Novel results obtained from recoupling the chemical shift anisotropy of a single arginine in IKe phage, which is in contact with its DNA, further demonstrate this point. MAS NMR thus provides many new insights into phage structure, and on the other hand the richness, complexity and variety of bacteriophage systems provide opportunities for new NMR methodologies and technique developments.
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Affiliation(s)
- Amir Goldbourt
- School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 6997801, Israel.
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4
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Aharoni T, Goldbourt A. Rapid automated determination of chemical shift anisotropy values in the carbonyl and carboxyl groups of fd-y21m bacteriophage using solid state NMR. JOURNAL OF BIOMOLECULAR NMR 2018; 72:55-67. [PMID: 30141148 DOI: 10.1007/s10858-018-0206-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 08/17/2018] [Indexed: 06/08/2023]
Abstract
Determination of chemical shift anisotropy (CSA) in immobilized proteins and protein assemblies is one of several tools to determine protein dynamics on the timescales of microseconds and faster. The large CSA values of C=O groups in the rigid limit makes them in particular attractive for measurements of large amplitude motions, or their absence. In this study, we implement a 3D R-symmetry-based sequence that recouples the second spatial component of the 13C CSA with the corresponding isotropic 13C'-13C cross-peaks in order to probe backbone and sidechain dynamics in an intact fd-y21m filamentous phage viral capsid. The assignment of the isotropic cross-peaks and the analysis were conducted automatically using a new software named 'Raven'. The software can be utilized to auto-assign any 2D 13C-13C or 15N-13C spectrum given a previously-determined assignment table and generates simultaneously all intensity curves acquired in the third dimension. Here, all CSA spectra were automatically generated, and subsequently matched against a simulated set of CSA curves to yield their values. For the multi-copy, 50-residue-long protein capsid of fd-y21m, the backbone of the helical region is rigid, with reduced CSA values of ~ 12.5 kHz (~ 83 ppm). The N-terminus shows motionally-averaged CSA lineshapes and the carboxylic sidechain groups of four residues indicate large amplitude motions for D4, D5, D12 and E20. The current results further strengthen our previous studies of 15N CSA values and are in agreement with qualitative analysis of 13C-13C dipolar build-up curves, which were automatically obtained using our software. Our automated analysis technique is general and can be applied to study protein structure and dynamics, with data resulting from experiments that probe different variables such as relaxation rates and scaled anisotropic interactions.
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Affiliation(s)
- Tom Aharoni
- School of Chemistry, The Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv, 6997801, Tel Aviv, Israel
| | - Amir Goldbourt
- School of Chemistry, The Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv, 6997801, Tel Aviv, Israel.
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5
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Aharoni T, Goldbourt A. Dynamics and Rigidity of an Intact Filamentous Bacteriophage Virus Probed by Magic Angle Spinning NMR. Chemistry 2018; 24:8737-8741. [PMID: 29660798 DOI: 10.1002/chem.201800532] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 04/11/2018] [Indexed: 12/12/2022]
Abstract
The capsid dynamics of filamentous bacteriophages is related to their function, stability, and interactions with the genome, and can be assessed by measuring the chemical shift anisotropy (CSA) of 15 N amides, which are sensitive to large amplitude motions. In this study, CSA recoupling experiments under magic-angle spinning NMR were used to probe the dynamics of the y21m capsid mutant of fd bacteriophage. Based on fitting the generated CSA lineshapes, residues located in the N-terminus undergo increased motional amplitudes suggesting its global motion, whereas other backbone residues are rigid, and imply a tight hydrophobic packing of the phage.
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Affiliation(s)
- Tom Aharoni
- School of Chemistry, The Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv, 6997801, Israel
| | - Amir Goldbourt
- School of Chemistry, The Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv, 6997801, Israel
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Ohgo K, Dabalos CL, Kumashiro KK. Solid-State NMR Spectroscopy and Isotopic Labeling Target Abundant Dipeptide Sequences in Elastin’s Hydrophobic Domains. Macromolecules 2018. [DOI: 10.1021/acs.macromol.7b02616] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kosuke Ohgo
- Department of Chemistry, University of Hawaii, 2545 McCarthy Mall, Honolulu, Hawaii 96822, United States
| | - Chester L. Dabalos
- Department of Chemistry, University of Hawaii, 2545 McCarthy Mall, Honolulu, Hawaii 96822, United States
| | - Kristin K. Kumashiro
- Department of Chemistry, University of Hawaii, 2545 McCarthy Mall, Honolulu, Hawaii 96822, United States
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Ge Y, Hung I, Liu X, Liu M, Gan Z, Li C. Measurement of amide proton chemical shift anisotropy in perdeuterated proteins using CSA amplification. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 284:33-38. [PMID: 28957683 DOI: 10.1016/j.jmr.2017.09.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 09/07/2017] [Accepted: 09/16/2017] [Indexed: 06/07/2023]
Abstract
Measuring 1H chemical shift anisotropy (CSA) is useful for probing proton environments and dynamics but remains a challenge due to strong homonuclear interaction and relatively small shift anisotropy, especially in proteins with multiple proton sites. Here the extended chemical shift anisotropy amplification (xCSA) method is applied for amide proton CSA measurement in uniformly 2H enriched proteins under fast magic angle spinning. The xCSA method is capable of distinguishing the sign of the CSA asymmetry parameter, complimenting other multiple-pulse recoupling methods. A three-dimensional xCSA experiment is demonstrated for measuring the proton CSA of amide sites in aGB1 protein sample and the possible correlation of amide proton CSA with protein secondary structure is discussed.
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Affiliation(s)
- Yuwei Ge
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China; University of Chinese Academy of Sciences, Beijing 100049, China; Center of Interdisciplinary Magnetic Resonance, National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, FL 32310, USA
| | - Ivan Hung
- Center of Interdisciplinary Magnetic Resonance, National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, FL 32310, USA
| | - Xiaoli Liu
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Maili Liu
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Zhehong Gan
- Center of Interdisciplinary Magnetic Resonance, National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, FL 32310, USA.
| | - Conggang Li
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China.
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Soss SE, Flynn PF, Iuliucci RJ, Young RP, Mueller LJ, Hartman J, Beran GJO, Harper JK. Measuring and Modeling Highly Accurate
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N Chemical Shift Tensors in a Peptide. Chemphyschem 2017; 18:2225-2232. [DOI: 10.1002/cphc.201700357] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 06/08/2017] [Indexed: 11/06/2022]
Affiliation(s)
- Sarah E. Soss
- Department of Chemistry University of Utah Salt Lake City UT 84112 USA
| | - Peter F. Flynn
- Department of Chemistry University of Utah Salt Lake City UT 84112 USA
| | - Robbie J. Iuliucci
- Department of Chemistry Washington and Jefferson College 60 Lincoln Street Washington PA 15301 USA
| | - Robert P. Young
- Department of Chemistry University of California Riverside CA 92521 USA
| | | | - Joshua Hartman
- Department of Chemistry University of California Riverside CA 92521 USA
| | | | - James K. Harper
- Department of Chemistry University of Central Florida 4111 Libra Drive Orlando FL 32816 USA
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