Mercury ion(Hg^(2+)),a highly noxious of heavy metalion,has detrimental effects on the ecological environment and human health.Herein,we have developed an exonuclease III(Exo III)assisted catalytic hairpin assembly fo...Mercury ion(Hg^(2+)),a highly noxious of heavy metalion,has detrimental effects on the ecological environment and human health.Herein,we have developed an exonuclease III(Exo III)assisted catalytic hairpin assembly formation of a trivalent G-quadruplex/hemin DNAzyme for colorimetric detection of Hg^(2+).A hairpin DNA(Hr)was designed with thymine-Hg^(2+)-thymine pairs that catalyzed by Exo III is prompted to happen upon binding Hg^(2+).A released DNA fragment triggers the catalytic assembly of other three hairpins(H1,H2,and H3)to form many trivalent G-quadruplex/hemin DNA enzymes for signal output.The developed sensor shows a dynamic range from 2 pM to 2μM,with an impressively low detection limit of 0.32 pM for Hg^(2+)detection.Such a sensor also has good selectivity toward Hg^(2+)detection in the presence of other common metal ions.This strategy shows the great potential for visual detection with portable type.展开更多
A heroin-binding DNA G-quadruplex （also known as a heroin aptamer or DNAzyme） has been previously re- ported to be able to enhance the peroxidase activity of heroin. In this work, we described a DNAzyme structure th...A heroin-binding DNA G-quadruplex （also known as a heroin aptamer or DNAzyme） has been previously re- ported to be able to enhance the peroxidase activity of heroin. In this work, we described a DNAzyme structure that had an effector-recognizing part appearing as a single stranded DNA linkage flanked by two split G-quadruplex halves. Hybridization of the single stranded part in the enzyme with a perfectly matched DNA strand （effector） formed a rigid DNA duplex between the two G-quadruplex halves and thus efficiently suppressed the enzymatic activity of the G-quadruplex/hemin complex, while the mismatched effector strand was not able to regulate the peroxidase activity effectively. With 2,2＇-azinobis（3-ethylbenzthiazoline）-6-sulfonic acid （ABTS） as an oxidizable substrate, we were able to characterize the formation of the re-engineered G-quadruplex/hemin complex and verify its switchable peroxidase activity. Our results show that the split G-quadruplex is an especially useful module to design low-cost and label-free sensors toward various biologically or environmentally interesting targets.展开更多
The concentration of macromolecules in cells can reach up to 50-400 mg/mL.They occupy 40%(volume fraction)of the whole cellar space,known as molecular crowding.The diluted solution condition in vitro is different from...The concentration of macromolecules in cells can reach up to 50-400 mg/mL.They occupy 40%(volume fraction)of the whole cellar space,known as molecular crowding.The diluted solution condition in vitro is different from the crowded physiological condition in vivo.Therefore,the simulation of the physiological condition is necessary for obtaining the reliable results.It has been reported that G-quadruplex can bind to hemin to enhance its catalytic function for generating oxygen radicals,which can oxidize the lipids,proteins and DNA,thus leading to the damage of cells and tissues.In this paper,we chose PEG400 as molecular crowding reagent to simulate the molecular crowding environment in vivo.The catalytic characteristics of G-quadruplex-hemin complex in H202-ABTS system have been investigated[ABTS=2,2'-azinobis-(3-ethylbenzthiazoline-6-sulphonate)].The results showed that the binding affinity of G-quadruplex and hemin was decreased with the increasing of PEG400 concentration.They even lose their binding affinity in the presence of 40%PEG400.As a result,the peroxidase activity of G-quadruplex-hemin also reduced.Therefore,in physiological condition,hemin might not bind to G-quadruplex and it might not be the main reason to cause the damages of cells and tissues.展开更多
This work proposed a label-flee, cost-effective and fairly sensitive electrogenerated chemiluminescence （ECL） strategy for the specific detection of lysozyme based on the hemin/G-quadruplex hybrid. Gold nanoparticle...This work proposed a label-flee, cost-effective and fairly sensitive electrogenerated chemiluminescence （ECL） strategy for the specific detection of lysozyme based on the hemin/G-quadruplex hybrid. Gold nanoparticles were spread onto the chitosan thin-film as substrate to adsorb thiolated captures： a hairpin-structured DNA, integrating dual head-tail connected functional domains： one aptamer sequence for lysozyme and the other for hemin （iron（II1） proto-porphyrin IX）. In the presence of the both, the hairpin conformation unfolded and transformed into the hemird G-quadruplex motif, which quenched the ECL emission of underlaid quantum dots significantly via the consump- tion of dissolved oxygen as endogenous coreactant. This construction enabled a wide linear response to lysozyme, ranging from 20 μg.mL-1 to 5μg. mL-1, with a detection limit as low as 4.95 pgo mL-1 （e.g. 9.4 pmol·L^-1）, dem- onstrating the prospective utilization of DNA technologies in bioanalysis.展开更多
Massive efforts are currently being invested to improve the performance,versatility,and scope of applications of nucleic acid catalysts.G-quadruplex(G4)/hemin DNAzymes are of particular interest owing to their structu...Massive efforts are currently being invested to improve the performance,versatility,and scope of applications of nucleic acid catalysts.G-quadruplex(G4)/hemin DNAzymes are of particular interest owing to their structural programmability and chemical robustness.However,optimized catalytic efficiency is still bottleneck and the activation mechanism is unclear.Herein,we have designed a series of parallel G4s with different proximal cytosine(dC)derivatives to fine-tune the hemin-binding pocket for G4-DNAzymes.展开更多
Simian virus 40（SV40） is a polyomavirus and can induce a series of different tumors. The recognition of SV40 genome is crucial to tumor diagnosis and gene therapy. Herein, a sensitive and selective colorimetric meth...Simian virus 40（SV40） is a polyomavirus and can induce a series of different tumors. The recognition of SV40 genome is crucial to tumor diagnosis and gene therapy. Herein, a sensitive and selective colorimetric method for sequence-specific recognition of homopyrimidine-homopurine duplex DNA（dsDNA） of SV40（4424-4440, gp6） was established with a hairpin probe based upon the formation of triplex DNA. Hairpin probe 5＇-CCC TAC CCA TTT TTT CTT CTC TTT CCT GGG TAG GGC GGG TTG GG-3＇（HP） containing G-rich sequence and 17-bp triplex-forming sequence was used as the signal probe, which was stem-loop structure alone and exhibited low catalytic activity. Upon its binding to the target duplex of SV40, hairpin probe transferred from stem-loop structttre to parallel triplex DNA, accompanied by the recovery of catalytic activity of DNAzyme and a sharp increase of absorbance. Under optimum conditions, the absorbance was increased proportionally to the concentration of dsDNA over the range from 500 pmol/L to 40.0 nmol/L with a detection limit of 433 pmol/L. Moreover, satisfied results were obtained when the assay was used to recognize the mismatched sequences.展开更多
基金Supported by The Science and Technology Project of General Administration of Quality Supervision,Inspection and Quarantine (2015IK126)The Science and Technology Project of Changsha City of Hunan Province of China (KQ1602124).
文摘Mercury ion(Hg^(2+)),a highly noxious of heavy metalion,has detrimental effects on the ecological environment and human health.Herein,we have developed an exonuclease III(Exo III)assisted catalytic hairpin assembly formation of a trivalent G-quadruplex/hemin DNAzyme for colorimetric detection of Hg^(2+).A hairpin DNA(Hr)was designed with thymine-Hg^(2+)-thymine pairs that catalyzed by Exo III is prompted to happen upon binding Hg^(2+).A released DNA fragment triggers the catalytic assembly of other three hairpins(H1,H2,and H3)to form many trivalent G-quadruplex/hemin DNA enzymes for signal output.The developed sensor shows a dynamic range from 2 pM to 2μM,with an impressively low detection limit of 0.32 pM for Hg^(2+)detection.Such a sensor also has good selectivity toward Hg^(2+)detection in the presence of other common metal ions.This strategy shows the great potential for visual detection with portable type.
基金Acknowledgement This work was supported by National Natural Science Foundation of China （N o. 20605019）, PCSIRT （No IRT0756） and the Natural Science Foundation of Anhui Province Ministry of Education （No. K J20 1 2B 169）.
文摘A heroin-binding DNA G-quadruplex （also known as a heroin aptamer or DNAzyme） has been previously re- ported to be able to enhance the peroxidase activity of heroin. In this work, we described a DNAzyme structure that had an effector-recognizing part appearing as a single stranded DNA linkage flanked by two split G-quadruplex halves. Hybridization of the single stranded part in the enzyme with a perfectly matched DNA strand （effector） formed a rigid DNA duplex between the two G-quadruplex halves and thus efficiently suppressed the enzymatic activity of the G-quadruplex/hemin complex, while the mismatched effector strand was not able to regulate the peroxidase activity effectively. With 2,2＇-azinobis（3-ethylbenzthiazoline）-6-sulfonic acid （ABTS） as an oxidizable substrate, we were able to characterize the formation of the re-engineered G-quadruplex/hemin complex and verify its switchable peroxidase activity. Our results show that the split G-quadruplex is an especially useful module to design low-cost and label-free sensors toward various biologically or environmentally interesting targets.
基金Supported by the National Natural Science Foundation of China(Nos.21775128,21435004,21735004,21705024 and 21521004)the Program for Changjiang Scholars and Innovative Research Team in University,China(No.IRT13036).
文摘The concentration of macromolecules in cells can reach up to 50-400 mg/mL.They occupy 40%(volume fraction)of the whole cellar space,known as molecular crowding.The diluted solution condition in vitro is different from the crowded physiological condition in vivo.Therefore,the simulation of the physiological condition is necessary for obtaining the reliable results.It has been reported that G-quadruplex can bind to hemin to enhance its catalytic function for generating oxygen radicals,which can oxidize the lipids,proteins and DNA,thus leading to the damage of cells and tissues.In this paper,we chose PEG400 as molecular crowding reagent to simulate the molecular crowding environment in vivo.The catalytic characteristics of G-quadruplex-hemin complex in H202-ABTS system have been investigated[ABTS=2,2'-azinobis-(3-ethylbenzthiazoline-6-sulphonate)].The results showed that the binding affinity of G-quadruplex and hemin was decreased with the increasing of PEG400 concentration.They even lose their binding affinity in the presence of 40%PEG400.As a result,the peroxidase activity of G-quadruplex-hemin also reduced.Therefore,in physiological condition,hemin might not bind to G-quadruplex and it might not be the main reason to cause the damages of cells and tissues.
文摘This work proposed a label-flee, cost-effective and fairly sensitive electrogenerated chemiluminescence （ECL） strategy for the specific detection of lysozyme based on the hemin/G-quadruplex hybrid. Gold nanoparticles were spread onto the chitosan thin-film as substrate to adsorb thiolated captures： a hairpin-structured DNA, integrating dual head-tail connected functional domains： one aptamer sequence for lysozyme and the other for hemin （iron（II1） proto-porphyrin IX）. In the presence of the both, the hairpin conformation unfolded and transformed into the hemird G-quadruplex motif, which quenched the ECL emission of underlaid quantum dots significantly via the consump- tion of dissolved oxygen as endogenous coreactant. This construction enabled a wide linear response to lysozyme, ranging from 20 μg.mL-1 to 5μg. mL-1, with a detection limit as low as 4.95 pgo mL-1 （e.g. 9.4 pmol·L^-1）, dem- onstrating the prospective utilization of DNA technologies in bioanalysis.
基金support of the National Natural Science Foundation of China(nos.21977045 and 21635005)the Fundamental Research Funds for the Central Universities(no.02051430210)+5 种基金the Technology Innovation Fund Project of Nanjing University(no.020514913415)the Excellent Research Program of Nanjing University(no.ZYJH004)the funds of Nanjing University(no.020514912216)the Netherlands Organization for Scientific Research(NWO/CW)the CNRS,Agence Nationale de la Recherche(no.ANR-17-CE170010-01)Universitéde Bourgogne and Conseil Régional de Bourgogne(PARI),and the European Union(PO FEDER-FSE Bourgogne 2014/2020 programs).
文摘Massive efforts are currently being invested to improve the performance,versatility,and scope of applications of nucleic acid catalysts.G-quadruplex(G4)/hemin DNAzymes are of particular interest owing to their structural programmability and chemical robustness.However,optimized catalytic efficiency is still bottleneck and the activation mechanism is unclear.Herein,we have designed a series of parallel G4s with different proximal cytosine(dC)derivatives to fine-tune the hemin-binding pocket for G4-DNAzymes.
基金Supported by the National Natural Science Foundation of China（No.21375153）, the Fundamental Research Funds for the Central Universities of China（No. 131gzd05） and the Open Project of Beijing National Laboratory for Molecular Sciences, China.
文摘Simian virus 40（SV40） is a polyomavirus and can induce a series of different tumors. The recognition of SV40 genome is crucial to tumor diagnosis and gene therapy. Herein, a sensitive and selective colorimetric method for sequence-specific recognition of homopyrimidine-homopurine duplex DNA（dsDNA） of SV40（4424-4440, gp6） was established with a hairpin probe based upon the formation of triplex DNA. Hairpin probe 5＇-CCC TAC CCA TTT TTT CTT CTC TTT CCT GGG TAG GGC GGG TTG GG-3＇（HP） containing G-rich sequence and 17-bp triplex-forming sequence was used as the signal probe, which was stem-loop structure alone and exhibited low catalytic activity. Upon its binding to the target duplex of SV40, hairpin probe transferred from stem-loop structttre to parallel triplex DNA, accompanied by the recovery of catalytic activity of DNAzyme and a sharp increase of absorbance. Under optimum conditions, the absorbance was increased proportionally to the concentration of dsDNA over the range from 500 pmol/L to 40.0 nmol/L with a detection limit of 433 pmol/L. Moreover, satisfied results were obtained when the assay was used to recognize the mismatched sequences.
