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Maxwell M, Tan YJ, Lee R, Huber T, Otting G. Electrostatic Contribution to 19F Chemical Shifts in Fluorotryptophans in Proteins. Biochemistry 2023; 62:3255-3264. [PMID: 37934875 DOI: 10.1021/acs.biochem.3c00408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2023]
Abstract
DFT calculations indicate that the 19F chemical shifts of aromatic rings containing single fluorine substituents are sensitive to the electric fields and electric field gradients at the position of the fluorine atom. The present work explores whether long-range structure restraints can be gained from changes in 19F chemical shifts following mutations of charged to uncharged residues. 19F chemical shifts of fluorotryptophan residues were measured in two different proteins, GB1 and the NT* domain, following mutations of single asparagine residues to aspartic acid. Four different versions of fluorotryptophan were investigated, including 4-, 5-, 6-, and 7-fluorotryptophan, which were simultaneously installed by cell-free protein synthesis using 4-, 5-, 6-, and 7-fluoroindole as precursors for the tryptophan synthase present in the S30 extract. For comparison, the 1H chemical shifts of the corresponding nonfluorinated protein mutants produced with 13C-labeled tryptophan were also measured. The results show that the 19F chemical shifts respond more sensitively to the charge mutations than the 1H chemical shifts in the nonfluorinated references, but the chemical shift changes were much smaller than predicted by DFT calculations of fluoroindoles in the electric field of a partial charge in vacuum, indicating comprehensive dielectric shielding by water and protein. No straightforward correlation with the location of the charge mutation could be established.
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Affiliation(s)
- Michael Maxwell
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, Research School of Chemistry, Australian National University, Canberra 2601, Australian Capital Territory, Australia
| | - Yi Jiun Tan
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, Research School of Chemistry, Australian National University, Canberra 2601, Australian Capital Territory, Australia
| | - Richmond Lee
- School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong 2500, New South Wales, Australia
| | - Thomas Huber
- Research School of Chemistry, Australian National University, Canberra 2601, Australian Capital Territory, Australia
| | - Gottfried Otting
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, Research School of Chemistry, Australian National University, Canberra 2601, Australian Capital Territory, Australia
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Zhong L, Jeong S, Lee S, Mai TLH, Park J, Park J, Kim W, Yang C. Octafluoronaphthalene as a thermal-annealing-free volatile solid additive enables high-performance organic solar cells. Chem Commun (Camb) 2023; 59:12108-12111. [PMID: 37740305 DOI: 10.1039/d3cc03827k] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/24/2023]
Abstract
A thermal annealing-free solid additive octafluoronaphthalene was developed for high-performance organic solar cells. In an additive-modified device, an impressive power conversion efficiency of 18.59% from 17.27% was achieved with simultaneously enhanced current density from 26.86 to 27.53 mA cm-2 and fill factor from 74.34% to 78.85%.
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Affiliation(s)
- Lian Zhong
- School of Energy and Chemical Engineering, Perovtronics Research Center, Low Dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulju-gun, Ulsan 44919, South Korea.
| | - Seonghun Jeong
- School of Energy and Chemical Engineering, Perovtronics Research Center, Low Dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulju-gun, Ulsan 44919, South Korea.
| | - Seunglok Lee
- School of Energy and Chemical Engineering, Perovtronics Research Center, Low Dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulju-gun, Ulsan 44919, South Korea.
| | - Thi Le Huyen Mai
- School of Energy and Chemical Engineering, Perovtronics Research Center, Low Dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulju-gun, Ulsan 44919, South Korea.
| | - Jaeyeong Park
- School of Energy and Chemical Engineering, Perovtronics Research Center, Low Dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulju-gun, Ulsan 44919, South Korea.
| | - Jeewon Park
- School of Energy and Chemical Engineering, Perovtronics Research Center, Low Dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulju-gun, Ulsan 44919, South Korea.
| | - Wonjun Kim
- School of Energy and Chemical Engineering, Perovtronics Research Center, Low Dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulju-gun, Ulsan 44919, South Korea.
| | - Changduk Yang
- School of Energy and Chemical Engineering, Perovtronics Research Center, Low Dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulju-gun, Ulsan 44919, South Korea.
- Graduate School of Carbon Neutrality, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulju-gun, Ulsan 44919, South Korea
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Lu Y, Sun M, Xi N. Effects of fluorine bonding and nonbonding interactions on 19F chemical shifts. RSC Adv 2022; 12:32082-32096. [PMID: 36415555 PMCID: PMC9644289 DOI: 10.1039/d2ra06660b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 10/25/2022] [Indexed: 11/03/2023] Open
Abstract
19F-NMR signals are sensitive to local electrostatic fields and are useful in probing protein structures and dynamics. Here, we used chemically identical ortho-F nuclei in N-phenyl γ-lactams to investigate the relationship between 19F NMR chemical shifts and local environments. By varying the structures at the C5- and C7-substituents, we demonstrated that 19F shifts and Hammett coefficients in Hammett plots follow typical relationships in bonding interactions, while manifesting reverse correlations in nonbonding contacts. Quantum mechanics calculations revealed that one of the ortho-F nuclei engages in n → π* orbital delocalization between F lone pair electrons (n) and a C[double bond, length as m-dash]O/Ar[double bond, length as m-dash]N antibonding orbital (π*), and the other ortho-F nucleus exhibits n ↔ σ orbital polarization between the n electrons and the C-H σ bonding orbital. As 19F NMR spectroscopy find increasing use in molecular sensors and biological sciences, our findings are valuable for designing sensitive probes, elucidating molecular structures, and quantifying analytes.
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Affiliation(s)
- Yang Lu
- Institute of Drug Discovery Technology, Ningbo University Ningbo Zhejiang 315211 P. R. China
| | - Mingming Sun
- Department of Chemistry, Nanchang University 999 Xuefu Avenue Nanchang 330031 P. R. China
| | - Ning Xi
- Institute of Drug Discovery Technology, Ningbo University Ningbo Zhejiang 315211 P. R. China
- School of Medicine, Ningbo University Ningbo Zhejiang 315211 P. R. China
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