Ferricyanide-promoted oxidative activation of Nacylatedα-aminothioacids for amide bond formation withα-aminonitriles was recently shown to be a plausible pathway for prebiotic peptide synthesis.Herein we describe th...Ferricyanide-promoted oxidative activation of Nacylatedα-aminothioacids for amide bond formation withα-aminonitriles was recently shown to be a plausible pathway for prebiotic peptide synthesis.Herein we describe the finding that by adding sodium azide and thiols,ferricyanide oxidation can elicit highly efficient and clean conversion of fully unprotected peptide or protein thioacids in neutral aqueous media to the corresponding thioesters.This transformation enables the development of ferricyanide-promoted thioacid-based native chemical ligation(NCL)as a new redox-based method for chemical protein synthesis,which does not need to change pH and is therefore operationally easy for ligation at small scales.The effectiveness of the ferricyanide-promoted thioacid-based NCL was illustrated by synthesis of an ISG15-modified MDA5 segment under nondenaturing conditions and synthesis of an acetylated ubiquitin(Ub)-modified histone H2A through an N-to-C sequential ligation.This work broadens the concept of on-demand oxidative activation strategy for protein ligation and provides a new useful supplement to the repertoire of methods for chemical protein synthesis,particularly for studies on proteins carrying Ub family modifications.展开更多
E3 ubiquitin ligases catalyze the final step of ubiquitylation,a crucial post-translational modification involved in almost every process in eukaryotic cells.E3 ubiquitin ligases are key regulators of cellular events,...E3 ubiquitin ligases catalyze the final step of ubiquitylation,a crucial post-translational modification involved in almost every process in eukaryotic cells.E3 ubiquitin ligases are key regulators of cellular events,and the investigation into their functions and functioning mechanisms are research areas with great importance.Synthetic or semi-synthetic tools have greatly facilitated the research about the enzyme activity,distribution in different physiological events,and catalytic mechanism of E3 ubiquitin ligase.In this review,we summarize the development of chemical tools for E3 ubiquitin ligases with an emphasis on the synthetic routes.We show the utility of these chemical tools by briefly discussing their applications in biological research.展开更多
As one of the most widely existing post-translational modification models, ubiquitination regulates diverse cellular activities. In eukaryotes, K-branched ubiquitin chains play key roles in cell cycle and protein qual...As one of the most widely existing post-translational modification models, ubiquitination regulates diverse cellular activities. In eukaryotes, K-branched ubiquitin chains play key roles in cell cycle and protein quality control. However, the structural and biochemical properties of K-branched ubiquitin chains have not been well examined. Here we employed the synthetic linkage-and length-defined K-branched ubiquitin chains to examine their binding and hydrolysis properties in vitro. Quantitatively affinity determination of ubiquitin chains to the proteasome ubiquitin receptor S5 a indicated that the S5 a exhibited preference binding to K-branched chains over K-linked chains, but not K-conjugated chains. In addition, deubiquitination experiments were carried out and the results showed that K-branched chains were preferably hydrolyzed by proteasome-associated deubiquitinase Rpnll than homotypic Kor K-linked chains.展开更多
基金supported by the National Key R&D Program of China(grant no.2022YFC3401500)the National Natural Science Foundation of China(grant nos.22137005,92253302,and 22227810 for L.Liu,21877024 for Y.M.Li)+1 种基金the China Postdoctoral Science Foundation(grant nos.2021M691747 for G.C.Chu,2021M701862 and 2022T150347 for L.J.Liang)New Cornerstone Science Foundation.
文摘Ferricyanide-promoted oxidative activation of Nacylatedα-aminothioacids for amide bond formation withα-aminonitriles was recently shown to be a plausible pathway for prebiotic peptide synthesis.Herein we describe the finding that by adding sodium azide and thiols,ferricyanide oxidation can elicit highly efficient and clean conversion of fully unprotected peptide or protein thioacids in neutral aqueous media to the corresponding thioesters.This transformation enables the development of ferricyanide-promoted thioacid-based native chemical ligation(NCL)as a new redox-based method for chemical protein synthesis,which does not need to change pH and is therefore operationally easy for ligation at small scales.The effectiveness of the ferricyanide-promoted thioacid-based NCL was illustrated by synthesis of an ISG15-modified MDA5 segment under nondenaturing conditions and synthesis of an acetylated ubiquitin(Ub)-modified histone H2A through an N-to-C sequential ligation.This work broadens the concept of on-demand oxidative activation strategy for protein ligation and provides a new useful supplement to the repertoire of methods for chemical protein synthesis,particularly for studies on proteins carrying Ub family modifications.
文摘E3 ubiquitin ligases catalyze the final step of ubiquitylation,a crucial post-translational modification involved in almost every process in eukaryotic cells.E3 ubiquitin ligases are key regulators of cellular events,and the investigation into their functions and functioning mechanisms are research areas with great importance.Synthetic or semi-synthetic tools have greatly facilitated the research about the enzyme activity,distribution in different physiological events,and catalytic mechanism of E3 ubiquitin ligase.In this review,we summarize the development of chemical tools for E3 ubiquitin ligases with an emphasis on the synthetic routes.We show the utility of these chemical tools by briefly discussing their applications in biological research.
基金supported by the National Natural Science Foundation of China(Nos. U1732161, 91753120)
文摘As one of the most widely existing post-translational modification models, ubiquitination regulates diverse cellular activities. In eukaryotes, K-branched ubiquitin chains play key roles in cell cycle and protein quality control. However, the structural and biochemical properties of K-branched ubiquitin chains have not been well examined. Here we employed the synthetic linkage-and length-defined K-branched ubiquitin chains to examine their binding and hydrolysis properties in vitro. Quantitatively affinity determination of ubiquitin chains to the proteasome ubiquitin receptor S5 a indicated that the S5 a exhibited preference binding to K-branched chains over K-linked chains, but not K-conjugated chains. In addition, deubiquitination experiments were carried out and the results showed that K-branched chains were preferably hydrolyzed by proteasome-associated deubiquitinase Rpnll than homotypic Kor K-linked chains.
