Although the parallel incorporation of fluorinated aromatic amino acids(FAAAs)into proteins has been explored since 2010,the corresponding ^(19)F NMR investigation has been lacking to date.To assess the potential of t...Although the parallel incorporation of fluorinated aromatic amino acids(FAAAs)into proteins has been explored since 2010,the corresponding ^(19)F NMR investigation has been lacking to date.To assess the potential of the parallel incorporation of FAAAs in studies of protein structure,dynamics and interactions,we examine the protein yields,fluorine incorporation efficiencies,and ^(19)F NMR spectra upon simultaneously incorporating FAAAs including 3-fluorotyrosine(3FY),4-fluorophenylalanine(4FF)and 5-fluorotryptophan(5FW)into two model proteins:the structured protein GB1 domain(GB1)and the intrinsically disordered protein a-synuclein(a-syn).We found that the simultaneous incorporation of 3FY and 5FW achieved higher efficiency than combinations of 4FF and 5FW,4FF and 3FY,or 3FY,4FF and 5FW.Moreover,incorporating more types of FAAAs leads to a reduction in overall yield.The ^(19)F spectra of 3FY,4FF and 5FW residues in α-syn and GB1 exhibited good dispersion of chemical shifts.However,the GB1 spectrum showed complexity due to incomplete fluorination and interactions within aromatic cluster.This complexity could be significantly reduced by supplementing the medium with natural aromatic amino acids.To validate the advantage of ^(19)F NMR spectrum,we use 3FY-4FF-5FW-F94W-α-syn to investigate the interaction between α-syn and sodium dodecyl sulphate(SDS)micelle.Our study demonstrates that ^(19)F NMR spectroscopy of proteins with parallel incorporation of FAAAs provides a valuable tool for investigating protein conformation,dynamics and interactions.展开更多
The role of trifluoromethanesulfonate ion (OTf -) in asymmetric cyclopropanation of styrene catalyzed by ruthenium complex of chiral N, P ligand is investigated by in situ variable temperature 19 F NMR. The temperatur...The role of trifluoromethanesulfonate ion (OTf -) in asymmetric cyclopropanation of styrene catalyzed by ruthenium complex of chiral N, P ligand is investigated by in situ variable temperature 19 F NMR. The temperature of NMR experiment varies from 243 K to 283 K. After ethyl diazoacetate and styrene are added into the catalytic system, the process that the OTf - leaves from the central metal is observed from the change of the 19 F NMR spectra. Owing to the weakly coordinating behavior, trifluoromethanesulfonate ion can be easily removed from the central metal and replaced by substrates to form the reactive intermediate during the reaction. So that the catalytic reactivity can be improved greatly when the silver trifluoromethanesulfonate is added to the catalytic system.展开更多
基金supported by the Ministry of Science and Technology of China[grants 2021YFA1302602]the National Natural Science Foundation of China[grants 21925406,21991082,21921004]the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB0540000 and YSBR-068).
文摘Although the parallel incorporation of fluorinated aromatic amino acids(FAAAs)into proteins has been explored since 2010,the corresponding ^(19)F NMR investigation has been lacking to date.To assess the potential of the parallel incorporation of FAAAs in studies of protein structure,dynamics and interactions,we examine the protein yields,fluorine incorporation efficiencies,and ^(19)F NMR spectra upon simultaneously incorporating FAAAs including 3-fluorotyrosine(3FY),4-fluorophenylalanine(4FF)and 5-fluorotryptophan(5FW)into two model proteins:the structured protein GB1 domain(GB1)and the intrinsically disordered protein a-synuclein(a-syn).We found that the simultaneous incorporation of 3FY and 5FW achieved higher efficiency than combinations of 4FF and 5FW,4FF and 3FY,or 3FY,4FF and 5FW.Moreover,incorporating more types of FAAAs leads to a reduction in overall yield.The ^(19)F spectra of 3FY,4FF and 5FW residues in α-syn and GB1 exhibited good dispersion of chemical shifts.However,the GB1 spectrum showed complexity due to incomplete fluorination and interactions within aromatic cluster.This complexity could be significantly reduced by supplementing the medium with natural aromatic amino acids.To validate the advantage of ^(19)F NMR spectrum,we use 3FY-4FF-5FW-F94W-α-syn to investigate the interaction between α-syn and sodium dodecyl sulphate(SDS)micelle.Our study demonstrates that ^(19)F NMR spectroscopy of proteins with parallel incorporation of FAAAs provides a valuable tool for investigating protein conformation,dynamics and interactions.
文摘The role of trifluoromethanesulfonate ion (OTf -) in asymmetric cyclopropanation of styrene catalyzed by ruthenium complex of chiral N, P ligand is investigated by in situ variable temperature 19 F NMR. The temperature of NMR experiment varies from 243 K to 283 K. After ethyl diazoacetate and styrene are added into the catalytic system, the process that the OTf - leaves from the central metal is observed from the change of the 19 F NMR spectra. Owing to the weakly coordinating behavior, trifluoromethanesulfonate ion can be easily removed from the central metal and replaced by substrates to form the reactive intermediate during the reaction. So that the catalytic reactivity can be improved greatly when the silver trifluoromethanesulfonate is added to the catalytic system.
