Transient Induced Molecular Electronic Spectroscopy (TIMES) for study of protein-ligand interactions

Zhang, Tiantian; Ku, Ti-Hsuan; Han, Yuanyuan; Subramanian, Ramkumar; Niaz, Iftikhar Ahmad; Luo, Haiyong; Chang, Derrick; Huang, JianJang; Lo, Yu‐Hwa

doi:10.1038/srep35570

Cited by 5 publications

(5 citation statements)

References 28 publications

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“…According to the analytical model we developed previously, 17 the measured signal of TIMES system can be represented aswith the electrode area A , volume concentration of molecules (protein, ligand, or protein–ligand complex) n o, i , rate of molecular adsorption to the electrode surface K +, i , the coefficient with ζ being the zeta potential, molecular induced charge as a function of time q i ( t – t o i ), Q i ( t – t o i ) = γ i q i ( t – t o i ), and diffusion time for the molecule to transport transversely toward the electrode. 17 …”

Section: Results and Discussionmentioning

confidence: 99%

“…In this paper, we make original contributions in four areas through experiments and physical computations: (a) We demonstrate the accuracy of the TIMES technique by measuring the dissociation constant of lysozyme protein 10,11 with N-acetyl-D-glucosamine (NAG) 11−14 and its trimer, N,N′,N″-triacetylchitotriose (NAG 3 ) 15,16 1 shows the measured results of the dissociation constants between lysozyme and two ligands: NAG and NAG 3 . According to the analytical model we developed previously, 17 the measured signal of TIMES system can be represented as…”

Section: Introductionmentioning

confidence: 99%

“…for the molecule to transport transversely toward the electrode. 17 Utilizing electric signals for ligand, protein, and protein− ligand complex, protein−ligand dissociation constant can be obtained to estimate protein−ligand dissociation coefficient (K d ),…”

Section: Introductionmentioning

confidence: 99%

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Protein–Ligand Interaction Detection with a Novel Method of Transient Induced Molecular Electronic Spectroscopy (TIMES): Experimental and Theoretical Studies

et al. 2016

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Protein–ligand interaction detection without disturbances (e.g., surface immobilization, fluorescent labeling, and crystallization) presents a key question in protein chemistry and drug discovery. The emergent technology of transient induced molecular electronic spectroscopy (TIMES), which incorporates a unique design of microfluidic platform and integrated sensing electrodes, is designed to operate in a label-free and immobilization-free manner to provide crucial information for protein–ligand interactions in relevant physiological conditions. Through experiments and theoretical simulations, we demonstrate that the TIMES technique actually detects protein–ligand binding through signals generated by surface electric polarization. The accuracy and sensitivity of experiments were demonstrated by precise measurements of dissociation constant of lysozyme and N-acetyl-d-glucosamine (NAG) ligand and its trimer, NAG3. Computational fluid dynamics (CFD) computation is performed to demonstrate that the surface’s electric polarization signal originates from the induced image charges during the transition state of surface mass transport, which is governed by the overall effects of protein concentration, hydraulic forces, and surface fouling due to protein adsorption. Hybrid atomistic molecular dynamics (MD) simulations and free energy computation show that ligand binding affects lysozyme structure and stability, producing different adsorption orientation and surface polarization to give the characteristic TIMES signals. Although the current work is focused on protein–ligand interactions, the TIMES method is a general technique that can be applied to study signals from reactions between many kinds of molecules.

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Section: Results and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Protein–Ligand Interaction Detection with a Novel Method of Transient Induced Molecular Electronic Spectroscopy (TIMES): Experimental and Theoretical Studies

et al. 2016

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“…In this paper, we have extended the method of Transient Induced Molecular Electronic Signal (TIMES) reported earlier to directly measure the surface charge for any solution in contact with a conductive surface 24,25 . The results produce the amount and polarity of the surface charge in solution that is in contact with the electrode surface.…”

Section: Introductionmentioning

confidence: 99%

Measuring Electric Charge and Molecular Coverage on Electrode Surface from Transient Induced Molecular Electronic Signal (TIMES)

Chen

Tseng

Shi³

et al. 2019

Sci Rep

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Charge density and molecular coverage on the surface of electrode play major roles in the science and technology of surface chemistry and biochemical sensing. However, there has been no easy and direct method to characterize these quantities. By extending the method of Transient Induced Molecular Electronic Signal (TIMES) which we have used to measure molecular interactions, we are able to quantify the amount of charge in the double layers at the solution/electrode interface for different buffer strengths, buffer types, and pH values. Most uniquely, such capabilities can be applied to study surface coverage of immobilized molecules. As an example, we have measured the surface coverage for thiol-modified single-strand deoxyribonucleic acid (ssDNA) as anchored probe and 6-Mercapto-1-hexanol (MCH) as blocking agent on the platinum surface. Through these experiments, we demonstrate that TIMES offers a simple and accurate method to quantify surface charge and coverage of molecules on a metal surface, as an enabling tool for studies of surface properties and surface functionalization for biochemical sensing and reactions.

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“…Some time ago, we invented the method of transient induced molecular electronic signal (TIMES) to measure protein–ligand reactions in a label-free and immobilization-free manner. , In the TIMES technique, the reaction occurs in solution, and the reaction products are brought to an electrode surface via a microfluidic channel. The molecular constituents in the laminar flow approach the electrode by diffusion and induce changes in the surface charge on the electrode surface, generating a transient current that is amplified by a transimpedance amplifier connected to the electrode.…”

mentioning

confidence: 99%

Detecting Protein–Ligand Interaction from Integrated Transient Induced Molecular Electronic Signal (i-TIMES)

Chen

Tseng

Shi³

et al. 2020

Anal. Chem.

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Quantitative information about protein–ligand interactions is central to drug discovery. To obtain the quintessential reaction dissociation constant, ideally measurements of reactions should be performed without perturbations by molecular labeling or immobilization. The technique of transient induced molecular electrical signal (TIMES) has provided a promising technique to meet such requirements, and its performance in a microfluidic environment further offers the potential for high throughput and reduced consumption of reagents. In this work, we further the development by using integrated TIMES signal (i-TIMES) to greatly enhance the accuracy and reproducibility of the measurement. While the transient response may be of interest, the integrated signal directly measures the total amount of surface charge density resulted from molecules near the surface of electrode. The signals enable quantitative characterization of protein–ligand interactions. We have demonstrated the feasibility of i-TIMES technique using different biomolecules including lysozyme, N,N′,N″-triacetylchitotriose (TriNAG), aptamer, p-aminobenzamidine (pABA), bovine pancreatic ribonuclease A (RNaseA), and uridine-3′-phosphate (3′UMP). The results show i-TIMES is a simple and accurate technique that can bring tremendous value to drug discovery and research of intermolecular interactions.

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Transient Induced Molecular Electronic Spectroscopy (TIMES) for study of protein-ligand interactions

Cited by 5 publications

References 28 publications

Protein–Ligand Interaction Detection with a Novel Method of Transient Induced Molecular Electronic Spectroscopy (TIMES): Experimental and Theoretical Studies

Protein–Ligand Interaction Detection with a Novel Method of Transient Induced Molecular Electronic Spectroscopy (TIMES): Experimental and Theoretical Studies

Measuring Electric Charge and Molecular Coverage on Electrode Surface from Transient Induced Molecular Electronic Signal (TIMES)

Detecting Protein–Ligand Interaction from Integrated Transient Induced Molecular Electronic Signal (i-TIMES)

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