Guanosine-based hydrogels have attracted considerable attention because of their simplicity and easy preparation.However,the sugar moiety limits its further applications because of the necessity of sugar in the hydrog...Guanosine-based hydrogels have attracted considerable attention because of their simplicity and easy preparation.However,the sugar moiety limits its further applications because of the necessity of sugar in the hydrogel formation.This work reports a G-quadruplexes-based hydrogel consisting of guanine and peptide epitope to form a supramolecular hydrogel in the presence of metal cations.Using the metal ion-responsive peptide epitope from the ion channel to replace sugar motif at N9 position of guanosine results in a novel nucleopeptide.The results show that the gelation time,the diameter of nanofibers,the anisotropic property,and the mechanical property of the hydrogel can be simply controlled using metal cations.The magnesium and calcium ions direct the alignment of nanofibers to form anisotropic nano-bundles.The mechanistic studies indicate the formation of G-quadruplexes in the hydrogel.Compared to the storage modulus of nucleopeptide without the metal cation,adding zinc ions results in an over three-order increase in mechanical properties.Cytotoxicity experiment indicates the good biocompatibility of our hydrogel.Moreover,we demonstrate that the guanine-capped peptide could release STING agonist in a controlled manner.This work illustrates a simple way to modulate the property of the nucleopeptide hydrogel to develop soft materials.展开更多
The applicability of G-quadruplexes(G4s)as antiviral targets,therapeutic agents and diagnostic tools for coronavirus disease 2019(COVID-19)is currently being evaluated,which has drawn the extensive attention of the sc...The applicability of G-quadruplexes(G4s)as antiviral targets,therapeutic agents and diagnostic tools for coronavirus disease 2019(COVID-19)is currently being evaluated,which has drawn the extensive attention of the scientific community.During the COVID-19 pandemic,research in this field is rapidly accumulating.In this review,we summarize the latest achievements and breakthroughs in the use of G4s as antiviral targets,therapeutic agents and diagnostic tools for COVID-19,particularly using G4 ligands.Finally,strength and weakness regarding G4s in anti-SARS-CoV-2 field are highlighted for prospective future projects.展开更多
G-quadruplex secondary structures are four-stranded globular nucleic acid structures form in the specific DNA and RNA G-rich sequences with biological significance such as human telomeres,oncogene-promoter regions,rep...G-quadruplex secondary structures are four-stranded globular nucleic acid structures form in the specific DNA and RNA G-rich sequences with biological significance such as human telomeres,oncogene-promoter regions,replication initiation sites,and 5′and 3′-untranslated(UTR)regions.The non-canonical G-quadruplex secondary structures can readily form under physiologically relevant ionic conditions and are considered to be new molecular target for cancer therapeutics.This review discusses the essential progress in our lab related to the structures and functions of biologically relevant DNA G-quadruplexes in human gene promoters and telomeres,and the opportunities presented for the development of G-quadruplex-targeted smallmolecule drugs.展开更多
Human telomeric G-quadruplex plays a crucial role in regulating the genome stability. Despite extensive studies on structures and kinetics of monomeric G-quadruplex, the interaction between G-quadruplexes is still in ...Human telomeric G-quadruplex plays a crucial role in regulating the genome stability. Despite extensive studies on structures and kinetics of monomeric G-quadruplex, the interaction between G-quadruplexes is still in debate. In this work,we employ magnetic tweezers to investigate the folding and unfolding kinetics of two contiguous G-quadruplexes in 100-mM K~＋buffer. The interaction between G-quadruplexes and the consequent effect on the kinetics of G-quadruplex are revealed. The linker sequence between G-quadruplexes is further found to play an important role in the interaction between two G-quadruplexes. Our results provide a high-resolution insight into kinetics of multimeric G-quadruplexes and genome stability.展开更多
The Bloom helicase （BLM） gene product encodes a DNA helicase that functions in homologous recombination repair to prevent genomic instability. BLM is highly active in binding and unfolding G-quadruplexes （G4）, whi...The Bloom helicase （BLM） gene product encodes a DNA helicase that functions in homologous recombination repair to prevent genomic instability. BLM is highly active in binding and unfolding G-quadruplexes （G4）, which are non- canonical DNA structures formed by Hoogsteen base-pairing in guanine-rich sequences. Here we use single-molecule fluorescence resonance energy transfer （smFRET） to study the molecular mechanism of BLM-catalysed G4 unfolding and show that BLM unfolds G4 in two pathways. Our data enable us to propose a model in which the HRDC domain functions as a regulator of BLM, depending on the position of the HRDC domain of BLM in action： when HRDC binds to the G4 sequence, BLM may hold G4 in the unfolded state; otherwise, it may remain on the unfolded G4 transiently so that G4 can refold immediately.展开更多
Nucleic acids with G4 elements play a role in the formation of aggregates involved in intracellular phase transitions.Our previous studies suggest that different forms of DNA could act as an accelerating template in C...Nucleic acids with G4 elements play a role in the formation of aggregates involved in intracellular phase transitions.Our previous studies suggest that different forms of DNA could act as an accelerating template in Cu/Zn superoxide dismutase(SOD1)aggregation.Here,we examined the regulation of fo rmation and cytotoxicity of the SOD1 aggregates by single-stranded 12-merdeoxynucleotide oligomers(dN)_(12)(N=A,T,G,C;ssDNAs)under acidic conditions.The ssDNAs can be divided into two groups based on their roles in SOD1 binding,exposure of hydrophobic clusters in SOD1,accelerated formation,morphology and cytotoxicity of SOD1 aggregates.G-quadruplexes convert SOD1 into fibrillar aggregates as a template,a fact which was observed for the first time in the nucleic acid regulation of protein aggregation.Moreover,the fibrillar or fibril-like SOD1 species with a G-quadruplex provided by(dG)_(12)were less toxic than the amorphous species with(dN)_(12)(N=A,T).This study not only indicates that both morphology and cytotoxicity of protein aggregates can be regulated by the protein-bound DNAs,but also help us understand roles of nucleic aid G-quadruplexes in the formation of aggregates and membrane less organelles involved in intracellular phase transitions.展开更多
基金supported by the National Natural Science Foundation of China(82022038)。
文摘Guanosine-based hydrogels have attracted considerable attention because of their simplicity and easy preparation.However,the sugar moiety limits its further applications because of the necessity of sugar in the hydrogel formation.This work reports a G-quadruplexes-based hydrogel consisting of guanine and peptide epitope to form a supramolecular hydrogel in the presence of metal cations.Using the metal ion-responsive peptide epitope from the ion channel to replace sugar motif at N9 position of guanosine results in a novel nucleopeptide.The results show that the gelation time,the diameter of nanofibers,the anisotropic property,and the mechanical property of the hydrogel can be simply controlled using metal cations.The magnesium and calcium ions direct the alignment of nanofibers to form anisotropic nano-bundles.The mechanistic studies indicate the formation of G-quadruplexes in the hydrogel.Compared to the storage modulus of nucleopeptide without the metal cation,adding zinc ions results in an over three-order increase in mechanical properties.Cytotoxicity experiment indicates the good biocompatibility of our hydrogel.Moreover,we demonstrate that the guanine-capped peptide could release STING agonist in a controlled manner.This work illustrates a simple way to modulate the property of the nucleopeptide hydrogel to develop soft materials.
基金Financial support was provided by the National Key R&D Program of China(2019YFA0709202)the National Natural Science Foundation of China(91856205,21820102009,22237006,22107098,22122704)the Key Program of Frontier of Sciences(CAS QYZDJ-SSW-SLHO52).
文摘The applicability of G-quadruplexes(G4s)as antiviral targets,therapeutic agents and diagnostic tools for coronavirus disease 2019(COVID-19)is currently being evaluated,which has drawn the extensive attention of the scientific community.During the COVID-19 pandemic,research in this field is rapidly accumulating.In this review,we summarize the latest achievements and breakthroughs in the use of G4s as antiviral targets,therapeutic agents and diagnostic tools for COVID-19,particularly using G4 ligands.Finally,strength and weakness regarding G4s in anti-SARS-CoV-2 field are highlighted for prospective future projects.
文摘G-quadruplex secondary structures are four-stranded globular nucleic acid structures form in the specific DNA and RNA G-rich sequences with biological significance such as human telomeres,oncogene-promoter regions,replication initiation sites,and 5′and 3′-untranslated(UTR)regions.The non-canonical G-quadruplex secondary structures can readily form under physiologically relevant ionic conditions and are considered to be new molecular target for cancer therapeutics.This review discusses the essential progress in our lab related to the structures and functions of biologically relevant DNA G-quadruplexes in human gene promoters and telomeres,and the opportunities presented for the development of G-quadruplex-targeted smallmolecule drugs.
基金supported by the National Natural Science Foundation of China(Grant Nos.11474346 and 11774407)the Key Research Program of Frontier Sciences,Chinese Academy of Sciences(Grant No.QYZDB-SSW-SLH045)the National Key Research and Development Program,China(Grant No.2016YFA0301500)
文摘Human telomeric G-quadruplex plays a crucial role in regulating the genome stability. Despite extensive studies on structures and kinetics of monomeric G-quadruplex, the interaction between G-quadruplexes is still in debate. In this work,we employ magnetic tweezers to investigate the folding and unfolding kinetics of two contiguous G-quadruplexes in 100-mM K~＋buffer. The interaction between G-quadruplexes and the consequent effect on the kinetics of G-quadruplex are revealed. The linker sequence between G-quadruplexes is further found to play an important role in the interaction between two G-quadruplexes. Our results provide a high-resolution insight into kinetics of multimeric G-quadruplexes and genome stability.
基金supported by the National Natural Science Foundation of China(Grant Nos.11674382,11574381,and 11574382)the Key Research Program of Frontier Sciences,Chinese Academy of Sciences(Grant No.QYZDJ-SSW-SYS014)
文摘The Bloom helicase （BLM） gene product encodes a DNA helicase that functions in homologous recombination repair to prevent genomic instability. BLM is highly active in binding and unfolding G-quadruplexes （G4）, which are non- canonical DNA structures formed by Hoogsteen base-pairing in guanine-rich sequences. Here we use single-molecule fluorescence resonance energy transfer （smFRET） to study the molecular mechanism of BLM-catalysed G4 unfolding and show that BLM unfolds G4 in two pathways. Our data enable us to propose a model in which the HRDC domain functions as a regulator of BLM, depending on the position of the HRDC domain of BLM in action： when HRDC binds to the G4 sequence, BLM may hold G4 in the unfolded state; otherwise, it may remain on the unfolded G4 transiently so that G4 can refold immediately.
基金financially supported by the National Natural Science Foundation of China(Nos.21771073,22077046,21001047,21072074)the Fundamental Research Funds for the Central Universities(No.CCNU19TS052)。
文摘Nucleic acids with G4 elements play a role in the formation of aggregates involved in intracellular phase transitions.Our previous studies suggest that different forms of DNA could act as an accelerating template in Cu/Zn superoxide dismutase(SOD1)aggregation.Here,we examined the regulation of fo rmation and cytotoxicity of the SOD1 aggregates by single-stranded 12-merdeoxynucleotide oligomers(dN)_(12)(N=A,T,G,C;ssDNAs)under acidic conditions.The ssDNAs can be divided into two groups based on their roles in SOD1 binding,exposure of hydrophobic clusters in SOD1,accelerated formation,morphology and cytotoxicity of SOD1 aggregates.G-quadruplexes convert SOD1 into fibrillar aggregates as a template,a fact which was observed for the first time in the nucleic acid regulation of protein aggregation.Moreover,the fibrillar or fibril-like SOD1 species with a G-quadruplex provided by(dG)_(12)were less toxic than the amorphous species with(dN)_(12)(N=A,T).This study not only indicates that both morphology and cytotoxicity of protein aggregates can be regulated by the protein-bound DNAs,but also help us understand roles of nucleic aid G-quadruplexes in the formation of aggregates and membrane less organelles involved in intracellular phase transitions.
