The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Nongjian Tao - One of the best experts on this subject based on the ideXlab platform.
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measuring ligand Binding Kinetics to membrane proteins using virion nano oscillators
Journal of the American Chemical Society, 2018Co-Authors: Guan Da Syu, Shaopeng Wang, Xiaonan Shan, Brandon Henson, Prashant Desai, Heng Zhu, Nongjian TaoAbstract:Membrane proteins play vital roles in cellular signaling processes and serve as the most popular drug targets. A key task in studying cellular functions and developing drugs is to measure the Binding Kinetics of ligands with the membrane proteins. However, this has been a long-standing challenge because one must perform the measurement in a membrane environment to maintain the conformations and functions of the membrane proteins. Here, we report a new method to measure ligand Binding Kinetics to membrane proteins using self-assembled virion oscillators. Virions of human herpesvirus were used to display human G-protein-coupled receptors (GPCRs) on their viral envelopes. Each virion was then attached to a gold-coated glass surface via a flexible polymer to form an oscillator and driven into oscillation with an alternating electric field. By tracking changes in the oscillation amplitude in real-time with subnanometer precision, the Binding Kinetics between ligands and GPCRs was measured. We anticipate that t...
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study of small molecule membrane protein Binding Kinetics with nanodisc and charge sensitive optical detection
Analytical Chemistry, 2016Co-Authors: Yan Guan, Shaopeng Wang, Nongjian TaoAbstract:Nanodisc technology provides membrane proteins with a nativelike lipid bilayer and much-needed solubility and enables in vitro quantification of membrane protein Binding with ligands. However, it has been a challenge to measure interaction between small-molecule ligands and nanodisc-encapsulated membrane proteins, because the responses of traditional mass-based detection methods scale with the mass of the ligands. We have developed a charge-sensitive optical detection (CSOD) method for label-free measurement of the Binding Kinetics of low molecular mass ligands with nanodisc-encapsulated membrane proteins. This microplate-compatible method is sensitive to the charge instead of the mass of a ligand and is able to measure both large and small molecules in a potentially high-throughput format. Using CSOD, we measured the Binding Kinetics between peptide and small-molecule ligands and a nanodisc-encapsulated potassium ion channel protein, KcsA-Kv1.3. Both association and dissociation rate constants for these ligands are obtained for the first time. The CSOD results were validated by the consistency of the values with reported Binding affinities. In addition, we found that CSOD can tolerate up to 3.9% dimethyl sulfoxide (DMSO) and up to 10% serum, which shows its compatibility with realistic sample conditions.
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Study of Small-Molecule–Membrane Protein Binding Kinetics with Nanodisc and Charge-Sensitive Optical Detection
2016Co-Authors: Yan Guan, Shaopeng Wang, Nongjian TaoAbstract:Nanodisc technology provides membrane proteins with a nativelike lipid bilayer and much-needed solubility and enables in vitro quantification of membrane protein Binding with ligands. However, it has been a challenge to measure interaction between small-molecule ligands and nanodisc-encapsulated membrane proteins, because the responses of traditional mass-based detection methods scale with the mass of the ligands. We have developed a charge-sensitive optical detection (CSOD) method for label-free measurement of the Binding Kinetics of low molecular mass ligands with nanodisc-encapsulated membrane proteins. This microplate-compatible method is sensitive to the charge instead of the mass of a ligand and is able to measure both large and small molecules in a potentially high-throughput format. Using CSOD, we measured the Binding Kinetics between peptide and small-molecule ligands and a nanodisc-encapsulated potassium ion channel protein, KcsA-Kv1.3. Both association and dissociation rate constants for these ligands are obtained for the first time. The CSOD results were validated by the consistency of the values with reported Binding affinities. In addition, we found that CSOD can tolerate up to 3.9% dimethyl sulfoxide (DMSO) and up to 10% serum, which shows its compatibility with realistic sample conditions
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measurement of small molecule Binding Kinetics on a protein microarray by plasmonic based electrochemical impedance imaging
Analytical Chemistry, 2014Co-Authors: Wenbin Liang, Joshua Labaer, Shaopeng Wang, Fernanda Festa, Peter Wiktor, Wei Wang, Mitchell Magee, Nongjian TaoAbstract:We report on a quantitative study of small molecule Binding Kinetics on protein microarrays with plasmonic-based electrochemical impedance microscopy (P-EIM). P-EIM measures electrical impedance optically with high spatial resolution by converting a surface charge change to a surface plasmon resonance (SPR) image intensity change, and the signal is not scaled to the mass of the analyte. Using P-EIM, we measured Binding Kinetics and affinity between small molecule drugs (imatinib and SB202190) and their target proteins (kinases Abl1 and p38-α). The measured affinity values are consistent with reported values measured by an indirect competitive Binding assay. We also found that SB202190 has weak Bindings to ABL1 with KD > 10 μM, which is not reported in the literature. Furthermore, we found that P-EIM is less prone to nonspecific Binding, a long-standing issue in SPR. Our results show that P-EIM is a novel method for high-throughput measurement of small molecule Binding Kinetics and affinity, which is criti...
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measurement of small molecule Binding Kinetics on a protein microarray by plasmonic based electrochemical impedance imaging
Analytical Chemistry, 2014Co-Authors: Wenbin Liang, Joshua Labaer, Shaopeng Wang, Fernanda Festa, Peter Wiktor, Wei Wang, Mitchell Magee, Nongjian TaoAbstract:We report on a quantitative study of small molecule Binding Kinetics on protein microarrays with plasmonic-based electrochemical impedance microscopy (P-EIM). P-EIM measures electrical impedance optically with high spatial resolution by converting a surface charge change to a surface plasmon resonance (SPR) image intensity change, and the signal is not scaled to the mass of the analyte. Using P-EIM, we measured Binding Kinetics and affinity between small molecule drugs (imatinib and SB202190) and their target proteins (kinases Abl1 and p38-α). The measured affinity values are consistent with reported values measured by an indirect competitive Binding assay. We also found that SB202190 has weak Bindings to ABL1 with KD > 10 μM, which is not reported in the literature. Furthermore, we found that P-EIM is less prone to nonspecific Binding, a long-standing issue in SPR. Our results show that P-EIM is a novel method for high-throughput measurement of small molecule Binding Kinetics and affinity, which is critical to the understanding of small molecules in biological systems and discovery of small molecule drugs.
Laura H Heitman - One of the best experts on this subject based on the ideXlab platform.
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perspective implications of ligand receptor Binding Kinetics for therapeutic targeting of g protein coupled receptors
ACS Pharmacology & Translational Science, 2020Co-Authors: Wijnand J C Van Der Velden, Laura H Heitman, Mette M RosenkildeAbstract:The concept of ligand–receptor Binding Kinetics has been broadly applied in drug development pipelines focusing on G protein-coupled receptors (GPCRs). The ligand residence time (RT) for a receptor...
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a Binding Kinetics study of human adenosine a3 receptor agonists
Biochemical Pharmacology, 2018Co-Authors: Lizi Xia, Adriaan P Ijzerman, Athina Kyrizaki, Dilip K Tosh, Tirsa T Van Duijl, Jacomina Cornelia Roorda, Kenneth A Jacobson, Laura H HeitmanAbstract:The human adenosine A(3) (hA(3)) receptor has been suggested as a viable drug target in inflammatory diseases and in cancer. So far, a number of selective hA(3) receptor agonists (e.g. IB-MECA and 2-CI-IB-MECA) inducing anti-inflammatory or anticancer effects are under clinical investigation. Drug-target Binding Kinetics is increasingly recognized as another pharmacological parameter, next to affinity, for compound triage in the early phases of drug discovery. However, such a Kinetics-driven analysis has not yet been performed for the hA3 receptor. In this study, we first validated a competition association assay for adenosine A3 receptor agonists to determine the target interaction Kinetics. Affinities and Kinetic Rate Index (KRI) values of 11 ribofurano and 10 methanocarba nucleosides were determined in radioligand Binding assays. Afterwards, 15 analogues were further selected (KRI 1.35) for full Kinetics characterization. The structure-Kinetics relationships (SKR) were derived and longer residence times were associated with methanocarba and enlarged adenine N-6 and C2 substitutions. In addition, from a k(on)-k(off)K(D) kinetic map we divided the agonists into three subgroups. A residence time "cliff' was observed, which might be relevant to (N)-methanocarba derivatives' rigid C2-arylalkynyl substitutions. Our findings provide substantial evidence that, next to affinity, additional knowledge of Binding Kinetics is useful for developing and selecting new hA(3)R agonists in the early phase of the drug discovery process.
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from receptor Binding Kinetics to signal transduction a missing link in predicting in vivo drug action
Scientific Reports, 2017Co-Authors: Indira Nederpelt, Adriaan P Ijzerman, Maria Kuzikov, Wilbert De Witte, Patrick Schnider, Bruno Tuijt, Elizabeth C M De Lange, Laura H HeitmanAbstract:An important question in drug discovery is how to overcome the significant challenge of high drug attrition rates due to lack of efficacy and safety. A missing link in the understanding of determinants for drug efficacy is the relation between drug-target Binding Kinetics and signal transduction, particularly in the physiological context of (multiple) endogenous ligands. We hypothesized that the kinetic Binding parameters of both drug and endogenous ligand play a crucial role in determining cellular responses, using the NK1 receptor as a model system. We demonstrated that the Binding Kinetics of both antagonists (DFA and aprepitant) and endogenous agonists (NKA and SP) have significantly different effects on signal transduction profiles, i.e. potency values, in vitro efficacy values and onset rate of signal transduction. The antagonistic effects were most efficacious with slowly dissociating aprepitant and slowly associating NKA while the combination of rapidly dissociating DFA and rapidly associating SP had less significant effects on the signal transduction profiles. These results were consistent throughout different kinetic assays and cellular backgrounds. We conclude that knowledge of the relationship between in vitro drug-target Binding Kinetics and cellular responses is important to ultimately improve the understanding of drug efficacy in vivo.
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the added value of assessing ligand receptor Binding Kinetics in drug discovery
ACS Medicinal Chemistry Letters, 2016Co-Authors: Laura H Heitman, Adriaan P IjzermanAbstract:In the past decade drug research community has started to appreciate the indispensable role of ligand–receptor Binding Kinetics (BK) in drug discovery. Next to the classical equilibrium-based drug evaluation process with affinity and potency values as outcomes, kinetic investigation of the ligand–receptor interaction can aid compound triage in the hit-to-lead campaign and provide additional information to understand the molecular mechanism of drug action. Translational models incorporating BK are emerging as well, which represent powerful tools for the prediction of in vivo effects. In this viewpoint we will summarize some recent findings and discuss and emphasize the added value of ligand–receptor Binding Kinetics in drug research.
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agonists for the adenosine a1 receptor with tunable residence time a case for nonribose 4 amino 6 aryl 5 cyano 2 thiopyrimidines
Journal of Medicinal Chemistry, 2014Co-Authors: Julien Louvel, Johannes Brussee, Dong Guo, Marta Agliardi, Tamara A M Mocking, Roland Kars, Tan Phat Pham, Lizi Xia, Henk De Vries, Laura H HeitmanAbstract:We report the synthesis and evaluation of previously unreported 4-amino-6-aryl-5-cyano-2-thiopyrimidines as selective human adenosine A1 receptor (hA1AR) agonists with tunable Binding Kinetics, this without affecting their nanomolar affinity for the target receptor. They show a very diverse range of kinetic profiles (from 1 min (compound 52) to 1 h (compound 43)), and their structure–affinity relationships (SAR) and structure–Kinetics relationships (SKR) were established. When put in perspective with the increasing importance of Binding Kinetics in drug discovery, these results bring new evidence of the consequences of affinity-only driven selection of drug candidates, that is, the potential elimination of slightly less active compounds that may display preferable Binding Kinetics.
Shaopeng Wang - One of the best experts on this subject based on the ideXlab platform.
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measuring ligand Binding Kinetics to membrane proteins using virion nano oscillators
Journal of the American Chemical Society, 2018Co-Authors: Guan Da Syu, Shaopeng Wang, Xiaonan Shan, Brandon Henson, Prashant Desai, Heng Zhu, Nongjian TaoAbstract:Membrane proteins play vital roles in cellular signaling processes and serve as the most popular drug targets. A key task in studying cellular functions and developing drugs is to measure the Binding Kinetics of ligands with the membrane proteins. However, this has been a long-standing challenge because one must perform the measurement in a membrane environment to maintain the conformations and functions of the membrane proteins. Here, we report a new method to measure ligand Binding Kinetics to membrane proteins using self-assembled virion oscillators. Virions of human herpesvirus were used to display human G-protein-coupled receptors (GPCRs) on their viral envelopes. Each virion was then attached to a gold-coated glass surface via a flexible polymer to form an oscillator and driven into oscillation with an alternating electric field. By tracking changes in the oscillation amplitude in real-time with subnanometer precision, the Binding Kinetics between ligands and GPCRs was measured. We anticipate that t...
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study of small molecule membrane protein Binding Kinetics with nanodisc and charge sensitive optical detection
Analytical Chemistry, 2016Co-Authors: Yan Guan, Shaopeng Wang, Nongjian TaoAbstract:Nanodisc technology provides membrane proteins with a nativelike lipid bilayer and much-needed solubility and enables in vitro quantification of membrane protein Binding with ligands. However, it has been a challenge to measure interaction between small-molecule ligands and nanodisc-encapsulated membrane proteins, because the responses of traditional mass-based detection methods scale with the mass of the ligands. We have developed a charge-sensitive optical detection (CSOD) method for label-free measurement of the Binding Kinetics of low molecular mass ligands with nanodisc-encapsulated membrane proteins. This microplate-compatible method is sensitive to the charge instead of the mass of a ligand and is able to measure both large and small molecules in a potentially high-throughput format. Using CSOD, we measured the Binding Kinetics between peptide and small-molecule ligands and a nanodisc-encapsulated potassium ion channel protein, KcsA-Kv1.3. Both association and dissociation rate constants for these ligands are obtained for the first time. The CSOD results were validated by the consistency of the values with reported Binding affinities. In addition, we found that CSOD can tolerate up to 3.9% dimethyl sulfoxide (DMSO) and up to 10% serum, which shows its compatibility with realistic sample conditions.
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Study of Small-Molecule–Membrane Protein Binding Kinetics with Nanodisc and Charge-Sensitive Optical Detection
2016Co-Authors: Yan Guan, Shaopeng Wang, Nongjian TaoAbstract:Nanodisc technology provides membrane proteins with a nativelike lipid bilayer and much-needed solubility and enables in vitro quantification of membrane protein Binding with ligands. However, it has been a challenge to measure interaction between small-molecule ligands and nanodisc-encapsulated membrane proteins, because the responses of traditional mass-based detection methods scale with the mass of the ligands. We have developed a charge-sensitive optical detection (CSOD) method for label-free measurement of the Binding Kinetics of low molecular mass ligands with nanodisc-encapsulated membrane proteins. This microplate-compatible method is sensitive to the charge instead of the mass of a ligand and is able to measure both large and small molecules in a potentially high-throughput format. Using CSOD, we measured the Binding Kinetics between peptide and small-molecule ligands and a nanodisc-encapsulated potassium ion channel protein, KcsA-Kv1.3. Both association and dissociation rate constants for these ligands are obtained for the first time. The CSOD results were validated by the consistency of the values with reported Binding affinities. In addition, we found that CSOD can tolerate up to 3.9% dimethyl sulfoxide (DMSO) and up to 10% serum, which shows its compatibility with realistic sample conditions
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in situ drug receptor Binding Kinetics in single cells a quantitative label free study of anti tumor drug resistance
Scientific Reports, 2015Co-Authors: Laura Gonzalezmalerva, Seron Eaton, Shengtao Zhang, Xiaobo Yu, Hong-yuan Chen, Shaopeng Wang, Joshua LabaerAbstract:Many drugs are effective in the early stage of treatment, but patients develop drug resistance after a certain period of treatment, causing failure of the therapy. An important example is Herceptin, a popular monoclonal antibody drug for breast cancer by specifically targeting human epidermal growth factor receptor 2 (Her2). Here we demonstrate a quantitative Binding Kinetics analysis of drug-target interactions to investigate the molecular scale origin of drug resistance. Using a surface plasmon resonance imaging, we measured the in situ Herceptin-Her2 Binding Kinetics in single intact cancer cells for the first time, and observed significantly weakened Herceptin-Her2 interactions in Herceptin-resistant cells, compared to those in Herceptin-sensitive cells. We further showed that the steric hindrance of Mucin-4, a membrane protein, was responsible for the altered drug-receptor Binding. This effect of a third molecule on drug-receptor interactions cannot be studied using traditional purified protein methods, demonstrating the importance of the present intact cell-based Binding Kinetics analysis.
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measurement of small molecule Binding Kinetics on a protein microarray by plasmonic based electrochemical impedance imaging
Analytical Chemistry, 2014Co-Authors: Wenbin Liang, Joshua Labaer, Shaopeng Wang, Fernanda Festa, Peter Wiktor, Wei Wang, Mitchell Magee, Nongjian TaoAbstract:We report on a quantitative study of small molecule Binding Kinetics on protein microarrays with plasmonic-based electrochemical impedance microscopy (P-EIM). P-EIM measures electrical impedance optically with high spatial resolution by converting a surface charge change to a surface plasmon resonance (SPR) image intensity change, and the signal is not scaled to the mass of the analyte. Using P-EIM, we measured Binding Kinetics and affinity between small molecule drugs (imatinib and SB202190) and their target proteins (kinases Abl1 and p38-α). The measured affinity values are consistent with reported values measured by an indirect competitive Binding assay. We also found that SB202190 has weak Bindings to ABL1 with KD > 10 μM, which is not reported in the literature. Furthermore, we found that P-EIM is less prone to nonspecific Binding, a long-standing issue in SPR. Our results show that P-EIM is a novel method for high-throughput measurement of small molecule Binding Kinetics and affinity, which is criti...
Mian Long - One of the best experts on this subject based on the ideXlab platform.
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determining β2 integrin and intercellular adhesion molecule 1 Binding Kinetics in tumor cell adhesion to leukocytes and endothelial cells by a gas driven micropipette assay
Journal of Biological Chemistry, 2011Co-Authors: Chunfang Tong, Manliu Wang, Yuxin Gao, Yan Zhang, Shile Liang, Cheng Dong, Mian LongAbstract:Interactions between polymorphonuclear neutrophils (PMNs) and tumor cells have been reported to facilitate the adhesion and subsequent extravasation of tumor cells through the endothelium under blood flow, both of which are mediated by Binding beta(2)-integrin to intercellular adhesion molecule 1 (ICAM-1). Here the adhesions between humanWM9 metastatic melanoma cells, PMNs, and human pulmonary microvascular endothelial cells (HPMECs) were quantified by a gas-driven micropipette aspiration technique (GDMAT). Our data indicated that the cellular Binding affinity of PMN-WM9 pair was 3.9-fold higher than that of the PMN-HPMEC pair. However, the effective Binding affinities per molecular pair were comparable between the two cell pairs no matter whether WM9 cells or HPMECs were quiescent or cytokine-activated, indicating that the stronger adhesion between PMN-WM9 pair is mainly attributed to the high expression of ICAM-1 on WM9 cells. These results proposed an alternative mechanism, where WM9 melanoma cells adhere first with PMNs near vessel-wall regions and then bind to endothelial cells via PMNs under blood flow. In contrast, the adhesions between human MDA-MB-231 metastatic breast carcinoma cells and PMNs showed a comparable cellular Binding affinity to PMN-HPMEC pair because the ICAM-1 expressions on MDA-MB-231 cells and HPMECs are similar. Furthermore, differences were observed in the intrinsic forward and reverse rates of the beta(2)-integrin-ICAM-1 bond between PMN-TC and PMN-EC pairs. This GDMAT assay enables us to quantify the Binding Kinetics of cell adhesion molecules physiologically expressed on nucleated cells. The findings also further the understanding of leukocyte-facilitated tumor cell adhesion from the viewpoint of molecular Binding Kinetics.
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determining β2 integrin and intercellular adhesion molecule 1 Binding Kinetics in tumor cell adhesion to leukocytes and endothelial cells by a gas driven micropipette assay
Journal of Biological Chemistry, 2011Co-Authors: Chunfang Tong, Manliu Wang, Yuxin Gao, Yan Zhang, Shile Liang, Cheng Dong, Mian LongAbstract:Interactions between polymorphonuclear neutrophils (PMNs) and tumor cells have been reported to facilitate the adhesion and subsequent extravasation of tumor cells through the endothelium under blood flow, both of which are mediated by Binding β2-integrin to intercellular adhesion molecule 1 (ICAM-1). Here the adhesions between human WM9 metastatic melanoma cells, PMNs, and human pulmonary microvascular endothelial cells (HPMECs) were quantified by a gas-driven micropipette aspiration technique (GDMAT). Our data indicated that the cellular Binding affinity of PMN-WM9 pair was 3.9-fold higher than that of the PMN-HPMEC pair. However, the effective Binding affinities per molecular pair were comparable between the two cell pairs no matter whether WM9 cells or HPMECs were quiescent or cytokine-activated, indicating that the stronger adhesion between PMN-WM9 pair is mainly attributed to the high expression of ICAM-1 on WM9 cells. These results proposed an alternative mechanism, where WM9 melanoma cells adhere first with PMNs near vessel-wall regions and then bind to endothelial cells via PMNs under blood flow. In contrast, the adhesions between human MDA-MB-231 metastatic breast carcinoma cells and PMNs showed a comparable cellular Binding affinity to PMN-HPMEC pair because the ICAM-1 expressions on MDA-MB-231 cells and HPMECs are similar. Furthermore, differences were observed in the intrinsic forward and reverse rates of the β2-integrin-ICAM-1 bond between PMN-TC and PMN-EC pairs. This GDMAT assay enables us to quantify the Binding Kinetics of cell adhesion molecules physiologically expressed on nucleated cells. The findings also further the understanding of leukocyte-facilitated tumor cell adhesion from the viewpoint of molecular Binding Kinetics.
Wei Wang - One of the best experts on this subject based on the ideXlab platform.
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measurement of small molecule Binding Kinetics on a protein microarray by plasmonic based electrochemical impedance imaging
Analytical Chemistry, 2014Co-Authors: Wenbin Liang, Joshua Labaer, Shaopeng Wang, Fernanda Festa, Peter Wiktor, Wei Wang, Mitchell Magee, Nongjian TaoAbstract:We report on a quantitative study of small molecule Binding Kinetics on protein microarrays with plasmonic-based electrochemical impedance microscopy (P-EIM). P-EIM measures electrical impedance optically with high spatial resolution by converting a surface charge change to a surface plasmon resonance (SPR) image intensity change, and the signal is not scaled to the mass of the analyte. Using P-EIM, we measured Binding Kinetics and affinity between small molecule drugs (imatinib and SB202190) and their target proteins (kinases Abl1 and p38-α). The measured affinity values are consistent with reported values measured by an indirect competitive Binding assay. We also found that SB202190 has weak Bindings to ABL1 with KD > 10 μM, which is not reported in the literature. Furthermore, we found that P-EIM is less prone to nonspecific Binding, a long-standing issue in SPR. Our results show that P-EIM is a novel method for high-throughput measurement of small molecule Binding Kinetics and affinity, which is criti...
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measurement of small molecule Binding Kinetics on a protein microarray by plasmonic based electrochemical impedance imaging
Analytical Chemistry, 2014Co-Authors: Wenbin Liang, Joshua Labaer, Shaopeng Wang, Fernanda Festa, Peter Wiktor, Wei Wang, Mitchell Magee, Nongjian TaoAbstract:We report on a quantitative study of small molecule Binding Kinetics on protein microarrays with plasmonic-based electrochemical impedance microscopy (P-EIM). P-EIM measures electrical impedance optically with high spatial resolution by converting a surface charge change to a surface plasmon resonance (SPR) image intensity change, and the signal is not scaled to the mass of the analyte. Using P-EIM, we measured Binding Kinetics and affinity between small molecule drugs (imatinib and SB202190) and their target proteins (kinases Abl1 and p38-α). The measured affinity values are consistent with reported values measured by an indirect competitive Binding assay. We also found that SB202190 has weak Bindings to ABL1 with KD > 10 μM, which is not reported in the literature. Furthermore, we found that P-EIM is less prone to nonspecific Binding, a long-standing issue in SPR. Our results show that P-EIM is a novel method for high-throughput measurement of small molecule Binding Kinetics and affinity, which is critical to the understanding of small molecules in biological systems and discovery of small molecule drugs.
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label free measuring and mapping of Binding Kinetics of membrane proteins in single living cells
Nature Chemistry, 2012Co-Authors: Wei Wang, Shaopeng Wang, Nongjian Tao, Yunze Yang, Vinay J Nagaraj, Qiang LiuAbstract:Membrane proteins mediate a variety of cellular responses to extracellular signals. Although membrane proteins are studied intensively for their values as disease biomarkers and therapeutic targets, in situ investigation of the Binding Kinetics of membrane proteins with their ligands has been a challenge. Traditional approaches isolate membrane proteins and then study them ex situ, which does not reflect accurately their native structures and functions. We present a label-free plasmonic microscopy method to map the local Binding Kinetics of membrane proteins in their native environment. This analytical method can perform simultaneous plasmonic and fluorescence imaging, and thus make it possible to combine the strengths of both label-based and label-free techniques in one system. Using this method, we determined the distribution of membrane proteins on the surface of single cells and the local Binding kinetic constants of different membrane proteins. Furthermore, we studied the polarization of the membrane proteins on the cell surface during chemotaxis.
