Proteins are crucial to most biological processes, such as enzymes, and in various catalytic processes a dynamic motion is required. The dynamics of protein are embodied as a conformational change, which is closely re...Proteins are crucial to most biological processes, such as enzymes, and in various catalytic processes a dynamic motion is required. The dynamics of protein are embodied as a conformational change, which is closely related to the flexibility of protein. Recently, nanopore sensors have become accepted as a low cost and high throughput method to study the features of proteins. In this article, we used a SiN nanopore device to study the flexibility of T7 RNA polymerase（RNAP） and its complex with DNA promoter. By calculating full-width at half-maximum（FWHM） of Gaussian fits to the blockade histograms, we found that T7 RNAP becomes more flexible after binding DNA promoter. Moreover, the distribution of fractional current blockade suggests that flexibility alters due to a breath-like change of the volume.展开更多
Motion control of a single molecule through a solid-state nanopore offers a new perspective on detecting and analyzing single biomolecules.Repeat recapture of a single DNA molecule reveals the dynamics in DNA transloc...Motion control of a single molecule through a solid-state nanopore offers a new perspective on detecting and analyzing single biomolecules.Repeat recapture of a single DNA molecule reveals the dynamics in DNA translocation through a nanopore and may significantly increase the signal-to-noise ratio for DNA base distinguishing.However,the transient current at the moment of voltage reversal prevents the observation of instantly recaptured molecules and invalidates the continuous DNA ping-pong control.We performed and analyzed the DNA translocation and recapture experiment in a silicon nitride solid-state nanopore.Numerical calculation of molecular motion clearly shows the recapture dynamics with different delay times.The prohibited time when the data acquisition system is saturated by the transient current is derived by equivalent circuit analysis and finite element simulation.The COMSOL simulation reveals that the membrane capacitance plays an important role in determining the electric field distribution during the charging process.As a result of the transient charging process,a non-constant driving force pulls the DNA back to nanopores faster than theoretically predicted.The observed long time constant in the transient current trace is explained by the dielectric absorption of the membrane capacitor.展开更多
Recently,nanopores have been used in an essential technique for detecting single molecule with high sensitivity.The initial application of nanopores to DNA and RNA sequencing has been expanded to sensing proteins and ...Recently,nanopores have been used in an essential technique for detecting single molecule with high sensitivity.The initial application of nanopores to DNA and RNA sequencing has been expanded to sensing proteins and nanoparticles,including Bovine serum albumin,silica nanoparticles,polystyrene beads,and others.In our study,for the first time,a positively charged gold nanorod was investigated using a solid-state nanopore device.Various gold nanorods passed through the nanopore with different current blockages and duration times,providing a measurement of the nanorod diameter,length,and charge.Our findings indicate that nanopore sensing might be a new method for characterizing the size,shape,and charge of nanoparticles.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51622201,91733301,and 61571015)
文摘Proteins are crucial to most biological processes, such as enzymes, and in various catalytic processes a dynamic motion is required. The dynamics of protein are embodied as a conformational change, which is closely related to the flexibility of protein. Recently, nanopore sensors have become accepted as a low cost and high throughput method to study the features of proteins. In this article, we used a SiN nanopore device to study the flexibility of T7 RNA polymerase（RNAP） and its complex with DNA promoter. By calculating full-width at half-maximum（FWHM） of Gaussian fits to the blockade histograms, we found that T7 RNAP becomes more flexible after binding DNA promoter. Moreover, the distribution of fractional current blockade suggests that flexibility alters due to a breath-like change of the volume.
基金supported by the National Basic Research Program of China(2012CB933002)Strategic Priority Research Program(B)of the Chinese Academy of Sciences(XDB07030100)+1 种基金the financial aid from Open Research Fund Program of the State Key Laboratory of Low Dimensional Quantum Physics(KF201201)the support of Hundred Talent Program of Chinese Academy of Sciences
文摘Motion control of a single molecule through a solid-state nanopore offers a new perspective on detecting and analyzing single biomolecules.Repeat recapture of a single DNA molecule reveals the dynamics in DNA translocation through a nanopore and may significantly increase the signal-to-noise ratio for DNA base distinguishing.However,the transient current at the moment of voltage reversal prevents the observation of instantly recaptured molecules and invalidates the continuous DNA ping-pong control.We performed and analyzed the DNA translocation and recapture experiment in a silicon nitride solid-state nanopore.Numerical calculation of molecular motion clearly shows the recapture dynamics with different delay times.The prohibited time when the data acquisition system is saturated by the transient current is derived by equivalent circuit analysis and finite element simulation.The COMSOL simulation reveals that the membrane capacitance plays an important role in determining the electric field distribution during the charging process.As a result of the transient charging process,a non-constant driving force pulls the DNA back to nanopores faster than theoretically predicted.The observed long time constant in the transient current trace is explained by the dielectric absorption of the membrane capacitor.
基金supported by the National Basic Research Program of China(2011CB707600)the National Natural Science Foundation of China(61071050)the National High Technology Research and Development Program of China(2012AA02A103)
文摘Recently,nanopores have been used in an essential technique for detecting single molecule with high sensitivity.The initial application of nanopores to DNA and RNA sequencing has been expanded to sensing proteins and nanoparticles,including Bovine serum albumin,silica nanoparticles,polystyrene beads,and others.In our study,for the first time,a positively charged gold nanorod was investigated using a solid-state nanopore device.Various gold nanorods passed through the nanopore with different current blockages and duration times,providing a measurement of the nanorod diameter,length,and charge.Our findings indicate that nanopore sensing might be a new method for characterizing the size,shape,and charge of nanoparticles.
