1
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Newton LD, Pascu SI, Tyrrell RM, Eggleston IM. Development of a peptide-based fluorescent probe for biological heme monitoring. Org Biomol Chem 2019; 17:467-471. [PMID: 30574967 PMCID: PMC6350759 DOI: 10.1039/c8ob02290a] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2018] [Accepted: 12/18/2018] [Indexed: 02/01/2023]
Abstract
Heme plays a vital role in cell biology and dysregulation of heme levels is implicated in a wide range of diseases. However, monitoring heme levels in biological systems is currently not straightforward. A short synthetic peptide probe containing 7-azatryptophan is shown to bind hemin in vitro with quenching of the azatryptophan fluorescence. This chemical tool can be used to detect the change in free heme induced in human skin cells upon exposure to UVA irradiation.
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Affiliation(s)
- Laura D. Newton
- Department of Pharmacy and Pharmacology
, University of Bath
,
Bath BA2 7AY
, UK
.
| | - Sofia I. Pascu
- Department of Chemistry
, University of Bath
,
Bath BA2 7AY
, UK
| | - Rex M. Tyrrell
- Department of Pharmacy and Pharmacology
, University of Bath
,
Bath BA2 7AY
, UK
.
| | - Ian M. Eggleston
- Department of Pharmacy and Pharmacology
, University of Bath
,
Bath BA2 7AY
, UK
.
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2
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Durgannavar T, Kwon SJ, Ghisaidoobe ABT, Rho K, Kim JH, Yoon S, Kang HJ, Chung SJ. Label‐Free Detection of Protein Tyrosine Phosphatase 1B (PTP1B) by Using a Rationally Designed Förster Resonance Energy Transfer (FRET) Probe. Chembiochem 2018; 19:2495-2501. [DOI: 10.1002/cbic.201800529] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Indexed: 01/10/2023]
Affiliation(s)
| | - Se Jeong Kwon
- School of PharmacySungkyunkwan University Suwon 16419 Republic of Korea
| | | | - Kyungmin Rho
- Department of ChemistryDongguk University Seoul 100–715 Republic of Korea
| | - Ju Hwan Kim
- Department of ChemistryDongguk University Seoul 100–715 Republic of Korea
| | - Sun‐Young Yoon
- School of PharmacySungkyunkwan University Suwon 16419 Republic of Korea
| | - Hyo Jin Kang
- Department of ChemistryDongguk University Seoul 100–715 Republic of Korea
| | - Sang J. Chung
- School of PharmacySungkyunkwan University Suwon 16419 Republic of Korea
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3
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Yang X, Feng Y, Chong H, Wang D, Hu X, Pu J, Zhan CG, Liao F. High-throughput estimation of specific activities of enzyme/mutants in cell lysates through immunoturbidimetric assay of proteins. Anal Biochem 2017; 534:91-98. [DOI: 10.1016/j.ab.2017.05.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 05/14/2017] [Indexed: 01/02/2023]
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4
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Yang J, Li Q, Bian L. Spectroscopic analysis and docking simulation on the recognition and binding of TEM-1 β-lactamase with β-lactam antibiotics. Exp Ther Med 2017; 14:3288-3298. [PMID: 28912880 DOI: 10.3892/etm.2017.4853] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2016] [Accepted: 03/17/2017] [Indexed: 11/05/2022] Open
Abstract
The interaction between TEM-1 β-lactamase and antibiotics is very important in the hydrolysis of antibiotics. In the present study, the recognition and binding of TEM-1 β-lactamase with three β-lactam antibiotics, including penicillin G, cefalexin and cefoxitin, was investigated by fluorescence and ultraviolet-visible absorption spectra in combination with molecular docking in the temperature range of 278-288 K and under simulated physiological conditions. The results demonstrated that the fluorescence emissions of TEM-1 β-lactamase were extinguished by static quenching and the energy of TEM-1 β-lactamase was transferred in a non-radioactive manner. The binding of TEM-1 β-lactamase with the three antibiotics was a spontaneously exothermic process, with binding constants of 1.41×107, 7.81×106 and 5.43×104 at 278 K. Furthermore, binding was driven by enthalpy change and the binding forces between them were mainly hydrogen bonding and Van der Waals forces. A TEM-1 β-lactamase only bound with one antibiotic at a time and the binding capacity between them was closely associated with the functional groups and flexibility in the antibiotics. In addition, a conformational change occurred in the TEM-1 β-lactamases when they bound with the three antibiotics and TEM-1 β-lactamase-antibiotic complexes were formed. The present study provided an insight into the recognition and binding of TEM-1 β-lactamase with β-lactam antibiotics, which may be helpful for designing a novel substrate for TEM-1 β-lactamase and developing novel antibiotics that are resistant to the enzyme.
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Affiliation(s)
- Jianting Yang
- Department of Traditional Chinese Medicine, College of Life Science, Northwest University, Xi'an, Shaanxi 710069, P.R. China.,Drug and Equipment Department, Weapon Industry 521 Hospital, Xi'an, Shaanxi 710065, P.R. China
| | - Qian Li
- Department of Traditional Chinese Medicine, College of Life Science, Northwest University, Xi'an, Shaanxi 710069, P.R. China
| | - Liujiao Bian
- Department of Traditional Chinese Medicine, College of Life Science, Northwest University, Xi'an, Shaanxi 710069, P.R. China
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5
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Lee M, Peterson BR. Quantification of Small Molecule-Protein Interactions using FRET between Tryptophan and the Pacific Blue Fluorophore. ACS OMEGA 2016; 1:1266-1276. [PMID: 28058293 PMCID: PMC5204206 DOI: 10.1021/acsomega.6b00356] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 12/06/2016] [Indexed: 05/14/2023]
Abstract
We report a new method to quantify the affinity of small molecules for proteins. This method is based on Förster resonance energy transfer (FRET) between endogenous tryptophan (Trp) residues and the coumarin-derived fluorophore Pacific Blue (PB). Tryptophan residues are frequently found in proteins near ligand-binding sites, making this approach potentially applicable to a wide range of systems. To improve access to PB, we developed a scalable multigram synthesis of this fluorophore, starting with inexpensive 2,3,4,5-tetrafluorobenzoic acid. This route was used to synthesize fluorescent derivatives of biotin, as well as lower affinity thiobiotin, iminobiotin, and imidazolidinethione analogues that bind the protein streptavidin. Compared with previously published FRET acceptors for tryptophan, PB proved to be superior in both sensitivity and efficiency. These unique properties of PB enabled direct quantification of dissociation constants (Kd) as well as competitive inhibition constants (Ki) in the micromolar to nanomolar range. In comparison to analogous binding studies using fluorescence polarization, fluorescence quenching, or fluorescence enhancement, affinities determined using Trp-FRET were more precise and accurate as validated using independent isothermal titration calorimetry studies. FRET between tryptophan and PB represents a new tool for the characterization of protein-ligand complexes.
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6
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Intrinsic Förster Resonance Energy Transfer Imaging Technique for Detection of Native Protein in Live Cells. B KOREAN CHEM SOC 2016. [DOI: 10.1002/bkcs.10639] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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7
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Pu J, Hu X, Liao J, Li YW, Qin JL, Xie YL, Zhan CG, Yang XL, Liao F. Achievement of linear response for competitive bioaffinity assays of ligands: criteria of optimized interaction systems. RSC Adv 2016. [DOI: 10.1039/c6ra06426d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
For a linear response, an optimized competitive bioaffinity assay of a ligand requiresCRT> 3 ×CPT,CPT> 50 ×KdR, andKdR> 260 ×KdX(CRTandCPTare concentrations of the probe and protein whileKdXandKdRareKdfor the ligand and probe, respectively).
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Affiliation(s)
- J. Pu
- Key Laboratory of Clinical Laboratory Diagnosis of the Education Ministry
- College of Laboratory Medicine
- Chongqing Medical University
- Chongqing 400016
- China
| | - X. L. Hu
- Key Laboratory of Clinical Laboratory Diagnosis of the Education Ministry
- College of Laboratory Medicine
- Chongqing Medical University
- Chongqing 400016
- China
| | - J. Liao
- Central Laboratory
- Yongchuan Hospital
- Chongqing Medical University
- Chongqing 402160
- China
| | - Y. W. Li
- Key Laboratory of Clinical Laboratory Diagnosis of the Education Ministry
- College of Laboratory Medicine
- Chongqing Medical University
- Chongqing 400016
- China
| | - J. L. Qin
- Key Laboratory of Clinical Laboratory Diagnosis of the Education Ministry
- College of Laboratory Medicine
- Chongqing Medical University
- Chongqing 400016
- China
| | - Y. L. Xie
- Key Laboratory of Clinical Laboratory Diagnosis of the Education Ministry
- College of Laboratory Medicine
- Chongqing Medical University
- Chongqing 400016
- China
| | - C.-G. Zhan
- Molecular Modeling and Biopharmaceutical Center
- Department of Pharmaceutical Sciences
- College of Pharmacy
- University of Kentucky
- Lexington
| | - X. L. Yang
- Key Laboratory of Clinical Laboratory Diagnosis of the Education Ministry
- College of Laboratory Medicine
- Chongqing Medical University
- Chongqing 400016
- China
| | - F. Liao
- Key Laboratory of Clinical Laboratory Diagnosis of the Education Ministry
- College of Laboratory Medicine
- Chongqing Medical University
- Chongqing 400016
- China
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Kang HJ, Kim JH, Chung SJ. Homogeneous detection of caspase-3 using intrinsic fluorescence resonance energy transfer (iFRET). Biosens Bioelectron 2015; 67:413-8. [DOI: 10.1016/j.bios.2014.08.074] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 08/11/2014] [Accepted: 08/27/2014] [Indexed: 11/16/2022]
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9
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Sun Q, Tian H, Qu H, Sun D, Chen Z, Duan L, Zhang W, Qian J. Discrimination between streptavidin and avidin with fluorescent affinity-based probes. Analyst 2015; 140:4648-53. [DOI: 10.1039/c5an00585j] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
SPS3 showed a high fluorescence response toward streptavidin and could discriminate biotin receptor over-expressed Hela cells from other cells.
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Affiliation(s)
- Qian Sun
- Shanghai Key Laboratory of Functional Materials Chemistry
- School of Chemistry and Molecular Engineering
- East China University of Science and Technology
- Shanghai
- China
| | - Haiyu Tian
- Shanghai Key Laboratory of Functional Materials Chemistry
- School of Chemistry and Molecular Engineering
- East China University of Science and Technology
- Shanghai
- China
| | - Haoran Qu
- Shanghai Key Laboratory of Functional Materials Chemistry
- School of Chemistry and Molecular Engineering
- East China University of Science and Technology
- Shanghai
- China
| | - Deheng Sun
- School of Pharmacy
- East China University of Science and Technology
- Shanghai
- China
| | - Zhuo Chen
- School of Pharmacy
- East China University of Science and Technology
- Shanghai
- China
| | - Liping Duan
- National Institute of Parasitic Diseases
- Chinese Center for Disease Control and Prevention
- Shanghai
- China
| | - Weibing Zhang
- Shanghai Key Laboratory of Functional Materials Chemistry
- School of Chemistry and Molecular Engineering
- East China University of Science and Technology
- Shanghai
- China
| | - Junhong Qian
- Shanghai Key Laboratory of Functional Materials Chemistry
- School of Chemistry and Molecular Engineering
- East China University of Science and Technology
- Shanghai
- China
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10
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Ghisaidoobe ABT, Chung SJ. Intrinsic tryptophan fluorescence in the detection and analysis of proteins: a focus on Förster resonance energy transfer techniques. Int J Mol Sci 2014; 15:22518-38. [PMID: 25490136 PMCID: PMC4284722 DOI: 10.3390/ijms151222518] [Citation(s) in RCA: 510] [Impact Index Per Article: 51.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 11/08/2014] [Accepted: 11/18/2014] [Indexed: 12/18/2022] Open
Abstract
Förster resonance energy transfer (FRET) occurs when the distance between a donor fluorophore and an acceptor is within 10 nm, and its application often necessitates fluorescent labeling of biological targets. However, covalent modification of biomolecules can inadvertently give rise to conformational and/or functional changes. This review describes the application of intrinsic protein fluorescence, predominantly derived from tryptophan (λ EX ≈ 280 nm, λ EM ≈ 350 nm), in protein-related research and mainly focuses on label-free FRET techniques. In terms of wavelength and intensity, tryptophan fluorescence is strongly influenced by its (or the proteinlocal environment, which, in addition to fluorescence quenching, has been applied to study protein conformational changes. Intrinsic Förster resonance energy transfer (iFRET), a recently developed technique, utilizes the intrinsic fluorescence of tryptophan in conjunction with target-specific fluorescent probes as FRET donors and acceptors, respectively, for real time detection of native proteins.
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Affiliation(s)
| | - Sang J Chung
- Department of Chemistry, Dongguk University, Seoul 100-715, Korea.
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11
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Spindel S, Sapsford KE. Evaluation of optical detection platforms for multiplexed detection of proteins and the need for point-of-care biosensors for clinical use. SENSORS (BASEL, SWITZERLAND) 2014; 14:22313-41. [PMID: 25429414 PMCID: PMC4299016 DOI: 10.3390/s141222313] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 11/12/2014] [Accepted: 11/13/2014] [Indexed: 11/16/2022]
Abstract
This review investigates optical sensor platforms for protein multiplexing, the ability to analyze multiple analytes simultaneously. Multiplexing is becoming increasingly important for clinical needs because disease and therapeutic response often involve the interplay between a variety of complex biological networks encompassing multiple, rather than single, proteins. Multiplexing is generally achieved through one of two routes, either through spatial separation on a surface (different wells or spots) or with the use of unique identifiers/labels (such as spectral separation-different colored dyes, or unique beads-size or color). The strengths and weaknesses of conventional platforms such as immunoassays and new platforms involving protein arrays and lab-on-a-chip technology, including commercially-available devices, are discussed. Three major public health concerns are identified whereby detecting medically-relevant markers using Point-of-Care (POC) multiplex assays could potentially allow for a more efficient diagnosis and treatment of diseases.
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Affiliation(s)
- Samantha Spindel
- Division of Biology, Chemistry, and Materials Science Office of Science and Engineering Laboratories; U.S. Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, MD 20993, USA.
| | - Kim E Sapsford
- Division of Biology, Chemistry, and Materials Science Office of Science and Engineering Laboratories; U.S. Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, MD 20993, USA.
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12
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Yang X, Hu X, Xu B, Wang X, Qin J, He C, Xie Y, Li Y, Liu L, Liao F. Fluorometric titration approach for calibration of quantity of binding site of purified monoclonal antibody recognizing epitope/hapten nonfluorescent at 340 nm. Anal Chem 2014; 86:5667-72. [PMID: 24848296 DOI: 10.1021/ac501111h] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A fluorometric titration approach was proposed for the calibration of the quantity of monoclonal antibody (mcAb) via the quench of fluorescence of tryptophan residues. It applied to purified mcAbs recognizing tryptophan-deficient epitopes, haptens nonfluorescent at 340 nm under the excitation at 280 nm, or fluorescent haptens bearing excitation valleys nearby 280 nm and excitation peaks nearby 340 nm to serve as Förster-resonance-energy-transfer (FRET) acceptors of tryptophan. Titration probes were epitopes/haptens themselves or conjugates of nonfluorescent haptens or tryptophan-deficient epitopes with FRET acceptors of tryptophan. Under the excitation at 280 nm, titration curves were recorded as fluorescence specific for the FRET acceptors or for mcAbs at 340 nm. To quantify the binding site of a mcAb, a universal model considering both static and dynamic quench by either type of probes was proposed for fitting to the titration curve. This was easy for fitting to fluorescence specific for the FRET acceptors but encountered nonconvergence for fitting to fluorescence of mcAbs at 340 nm. As a solution, (a) the maximum of the absolute values of first-order derivatives of a titration curve as fluorescence at 340 nm was estimated from the best-fit model for a probe level of zero, and (b) molar quantity of the binding site of the mcAb was estimated via consecutive fitting to the same titration curve by utilizing such a maximum as an approximate of the slope for linear response of fluorescence at 340 nm to quantities of the mcAb. This fluorometric titration approach was proved effective with one mcAb for six-histidine and another for penicillin G.
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Affiliation(s)
- Xiaolan Yang
- Unit for Analytical Probes and Protein Biotechnology, Key Laboratory of Medical Laboratory Diagnostics of the Education Ministry, College of Laboratory Medicine, Chongqing Medical University , Chongqing 400016, China
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13
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Selective and sensitive homogenous assay of serum albumin with 1-anilinonaphthalene-8-sulphonate as a biosensor. Anal Chim Acta 2014; 829:60-7. [DOI: 10.1016/j.aca.2014.04.047] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 04/21/2014] [Accepted: 04/23/2014] [Indexed: 11/20/2022]
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14
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Zhang C, Yang X, Gao A, Hu X, Pu J, Liu H, Feng J, Liao J, Li Y, Liao F. Comparison of modification of a bacterial uricase withN-hydroxysuccinimide esters of succinate and carbonate of monomethoxyl poly(ethylene glycol). Biotechnol Appl Biochem 2014; 61:683-90. [DOI: 10.1002/bab.1215] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 02/05/2014] [Indexed: 01/15/2023]
Affiliation(s)
- Chun Zhang
- Unit for Analytical Probes and Protein Biotechnology; Key Laboratory of Clinical Laboratory Diagnostics of the Education Ministry; College of Laboratory Medicine; Chongqing Medical University; Chongqing People's Republic of China
| | - Xiaolan Yang
- Unit for Analytical Probes and Protein Biotechnology; Key Laboratory of Clinical Laboratory Diagnostics of the Education Ministry; College of Laboratory Medicine; Chongqing Medical University; Chongqing People's Republic of China
| | - Ang Gao
- Unit for Analytical Probes and Protein Biotechnology; Key Laboratory of Clinical Laboratory Diagnostics of the Education Ministry; College of Laboratory Medicine; Chongqing Medical University; Chongqing People's Republic of China
| | - Xiaolei Hu
- Unit for Analytical Probes and Protein Biotechnology; Key Laboratory of Clinical Laboratory Diagnostics of the Education Ministry; College of Laboratory Medicine; Chongqing Medical University; Chongqing People's Republic of China
| | - Jun Pu
- Unit for Analytical Probes and Protein Biotechnology; Key Laboratory of Clinical Laboratory Diagnostics of the Education Ministry; College of Laboratory Medicine; Chongqing Medical University; Chongqing People's Republic of China
| | - Hongbo Liu
- Unit for Analytical Probes and Protein Biotechnology; Key Laboratory of Clinical Laboratory Diagnostics of the Education Ministry; College of Laboratory Medicine; Chongqing Medical University; Chongqing People's Republic of China
| | - Juan Feng
- Unit for Analytical Probes and Protein Biotechnology; Key Laboratory of Clinical Laboratory Diagnostics of the Education Ministry; College of Laboratory Medicine; Chongqing Medical University; Chongqing People's Republic of China
| | - Juan Liao
- Unit for Analytical Probes and Protein Biotechnology; Key Laboratory of Clinical Laboratory Diagnostics of the Education Ministry; College of Laboratory Medicine; Chongqing Medical University; Chongqing People's Republic of China
| | - Yuanli Li
- Unit for Analytical Probes and Protein Biotechnology; Key Laboratory of Clinical Laboratory Diagnostics of the Education Ministry; College of Laboratory Medicine; Chongqing Medical University; Chongqing People's Republic of China
| | - Fei Liao
- Unit for Analytical Probes and Protein Biotechnology; Key Laboratory of Clinical Laboratory Diagnostics of the Education Ministry; College of Laboratory Medicine; Chongqing Medical University; Chongqing People's Republic of China
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15
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Kim JH, Sumranjit J, Kang HJ, Chung SJ. Discovery of coumarin derivatives as fluorescence acceptors for intrinsic fluorescence resonance energy transfer of proteins. ACTA ACUST UNITED AC 2014; 10:30-3. [DOI: 10.1039/c3mb70323a] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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16
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Long G, Zhang Y, Yang X, Pu J, Qin J, Liu L, Liao F. Facile characterization of the immobilization of streptavidin on magnetic submicron particles with a fluorescent probe of streptavidin. APPLIED SPECTROSCOPY 2013; 67:688-691. [PMID: 23735255 DOI: 10.1366/12-06963] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
To characterize streptavidin immobilization on magnetic submicron particles (MSPs), residual streptavidin after magnetic removal of immobilized streptavidin was quantified with N-biotinyl-N'-(1-naphthyl)-ethylenediamine (BNEDA) based on Förster resonance energy transfer. Residual BNEDA after magnetic removal of bound BNEDA was measured by its own fluorescence. Streptavidin was immobilized at about 12 mg per gram of MSPs and easily retained over 50% of its original activity. These assays facilitated optimized streptavidin immobilization on MSPs.
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Affiliation(s)
- Gaobo Long
- Unit for Analytical Probes and Protein Biotechnology, Key Laboratory of Clinical Laboratory Diagnostics of the Education Ministry, College of Laboratory Medicine, Chongqing Medical University, Chongiqng 400016, China
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17
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Long G, Yang XL, Zhang Y, Pu J, Liu L, Liu HB, Li YL, Liao F. Facile one-step coating approach to magnetic submicron particles with poly(ethylene glycol) coats and abundant accessible carboxyl groups. Int J Nanomedicine 2013; 8:791-807. [PMID: 23589687 PMCID: PMC3622656 DOI: 10.2147/ijn.s41411] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Purpose Magnetic submicron particles (MSPs) are pivotal biomaterials for magnetic separations in bioanalyses, but their preparation remains a technical challenge. In this report, a facile one-step coating approach to MSPs suitable for magnetic separations was investigated. Methods Polyethylene glycol) (PEG) was derived into PEG-bis-(maleic monoester) and maleic monoester-PEG-succinic monoester as the monomers. Magnetofluids were prepared via chemical co-precipitation and dispersion with the monomers. MSPs were prepared via one-step coating of magnetofluids in a water-in-oil microemulsion system of aerosol-OT and heptane by radical co-polymerization of such monomers. Results The resulting MSPs contained abundant carboxyl groups, exhibited negligible nonspecific adsorption of common substances and excellent suspension stability, appeared as irregular particles by electronic microscopy, and had submicron sizes of broad distribution by laser scattering. Saturation magnetizations and average particle sizes were affected mainly by the quantities of monomers used for coating magnetofluids, and steric hindrance around carboxyl groups was alleviated by the use of longer monomers of one polymerizable bond for coating. After optimizations, MSPs bearing saturation magnetizations over 46 emu/g, average sizes of 0.32 μm, and titrated carboxyl groups of about 0.21 mmol/g were obtained. After the activation of carboxyl groups on MSPs into N-hydroxysuccinimide ester, biotin was immobilized on MSPs and the resulting biotin-functionalized MSPs isolated the conjugate of streptavidin and alkaline phosphatase at about 2.1 mg/g MSPs; streptavidin was immobilized at about 10 mg/g MSPs and retained 81% ± 18% (n = 5) of the specific activity of the free form. Conclusion The facile approach effectively prepares MSPs for magnetic separations.
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Affiliation(s)
- Gaobo Long
- Unit for Analytical Probes and Protein Biotechnology, Key Laboratory of Clinical Laboratory Diagnostics of the Education Ministry, College of Laboratory Medicine, Chongqing Medical University, Chongqing, People's Republic of China
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18
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Gao A, Yang X, Zhang C, Long G, Pu J, Yuan Y, Liu H, Li Y, Liao F. Facile spectrophotometric assay of molar equivalents of N-hydroxysuccinimide esters of monomethoxyl poly-(ethylene glycol) derivatives. Chem Cent J 2012. [PMID: 23176729 PMCID: PMC3542108 DOI: 10.1186/1752-153x-6-142] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Background A new method is developed to quantify molar equivalents of
N-hydroxysuccinimide (NHS) esters of derivatives of monomethoxyl
poly-(ethylene glycol) (mPEG) in their preparations with NHS acetate ester
as the reference. Results NHS ester of succinic monoester or carbonate of mPEG of 5,000 Da was
synthesized and reacted with excessive ethanolamine in dimethylformamide at
25°C for 15 min. Residual ethanolamine was subsequently quantified by
absorbance at 420 nm after reaction with 2,4,6-trinitrobenzenesulfonic acid
(TNBS) at pH 9.2 for 15 min at 55°C followed by cooling with tap water.
Reaction products of ethanolamine and NHS esters of mPEG caused no
interference with TNBS assay of residual ethanolamine. Reaction between
ethanolamine and NHS acetate ester follows 1:1 stoichiometry. By the new
method, molar equivalents of NHS esters of carbonate and succinic monoester
of mPEG in their preparations were about 90% and 60% of their
theoretical values, respectively. During storage at 37°C in humid air,
the new method detected spontaneous hydrolyses of the two NHS esters of mPEG
more sensitively than the classical spectrophotometric method based on
absorbance at 260 nm of NHS released by reaction with ammonia in aqueous
solution. Conclusion The new method is favorable to quantify molar equivalents of NHS esters of
mPEG derivatives and thus control quality of their preparations.
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Affiliation(s)
- Ang Gao
- Unit for Analytical Probes and Protein Biotechnology, Key Laboratory of Medical Laboratory Diagnostics of the Education Ministry of China, College of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China.
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19
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zhang Y, Yang X, Liu L, Huang X, Huang Z, Pu J, Long G, Zhang L, Liu D, Xu B, Liao J, Liao F. Comparison of Förster-resonance-energy-transfer acceptors for tryptophan and tyrosine residues in native proteins as donors. J Fluoresc 2012; 23:147-57. [PMID: 23001429 DOI: 10.1007/s10895-012-1128-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2012] [Accepted: 09/05/2012] [Indexed: 11/28/2022]
Abstract
Homogenous bioaffinity analysis with tryptophan/tyrosine residues in native proteins as FÖrster-resonance-energy-transfer (FRET) donors is feasible when suitable fluorophors can act as FRET acceptors in ligands (FRET probes) and FRET efficiency in complexes of proteins and FRET probes is high enough. In complexes of proteins and FRET probes, suitable acceptors should have excitation peaks around 335 nm and high rotation freedom, are preferred to have sufficient quantum yields and excitation valleys around 280 nm. In protein binding sites mimicked with mixtures of neutral phosphate buffer and organic solvents, quantum yields of candidate acceptors are altered inconsistently but their excitation peaks show tiny changes. Fluorophores as acceptors in such FRET probes are buried inside glutathione-S-transferase and have low rotation freedom, but are localized on streptavidin surface and display high rotation freedom; FRET efficiency in complexes of streptavidin and its FRET probes is much stronger than that in complexes of glutathione-S-transferase and its FRET probes. Specially, the quantum yield is about 0.70 for free 1-naphthylamine probe in neutral phosphate buffer, about 0.50 for 1-naphthylamine probe bound by streptavidin, and about 0.15 for that bound by glutathione-S-transferase. The quantum yield is about 0.06 for free dansylamide probe, about 0.11 for dansylamide probe bound by streptavidin and about 0.27 for that bound by glutathione-S-transferase. Therefore, 1-naphthylamine and dansylamide are effective acceptors when they localize on surfaces of complexes of proteins and FRET probes.
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Affiliation(s)
- Yi zhang
- Unit for analytical probes and protein biotechnology, Key laboratory of medical laboratory diagnostics of the Education Ministry, College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China
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Yang X, Pu J, Zhao H, Li X, Liao J, Xie Y, Zhu S, Long G, Yuan Y, Liao F. Method to screen aromatic ligands in mixtures for quantitative affinities to target using magnetic separation of bound ligands along with HPLC and UV photometry detection. Mikrochim Acta 2011. [DOI: 10.1007/s00604-011-0696-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Yang X, Xie Y, Pu J, Zhao H, Liao J, Yuan Y, Zhu S, Long G, Zhang C, Yuan H, Chen Y, Liao F. Estimation of affinities of ligands in mixtures via magnetic recovery of target-ligand complexes and chromatographic analyses: chemometrics and an experimental model. BMC Biotechnol 2011; 11:44. [PMID: 21545719 PMCID: PMC3096923 DOI: 10.1186/1472-6750-11-44] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2010] [Accepted: 05/05/2011] [Indexed: 11/22/2022] Open
Abstract
Abstract Conclusions This new method is robust and effective for each mixture possessing a limited number of candidate ligands whose molar quantities have moderate differences, and its integration with PCS has promise to routinely practice the mixture-based library strategy.
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Affiliation(s)
- Xiaolan Yang
- Unit for Analytical Probes and Protein Biotechnology, Key Laboratory of Medical Laboratory Diagnostics of Ministry of Education, Department of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China
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Xie Y, Yang X, Pu J, Zhao Y, Zhang Y, Xie G, Zheng J, Yuan H, Liao F. Homogeneous competitive assay of ligand affinities based on quenching fluorescence of tyrosine/tryptophan residues in a protein via Főrster-resonance-energy-transfer. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2010; 77:869-76. [PMID: 20822950 DOI: 10.1016/j.saa.2010.08.021] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2010] [Accepted: 08/05/2010] [Indexed: 05/13/2023]
Abstract
A new homogeneous competitive assay of ligand affinities was proposed based on quenching the fluorescence of tryptophan/tyrosine residues in a protein via Főrster-resonance-energy-transfer using a fluorescent reference ligand as the acceptor. Under excitation around 280 nm, the fluorescence of a protein or a bound acceptor was monitored upon competitive binding against a nonfluorescent candidate ligand. Chemometrics for deriving the binding ratio of the acceptor with either fluorescence signal was discussed; the dissociation constant (K(d)) of a nonfluorescent candidate ligand was calculated from its concentration to displace 50% binding of the acceptor. N-biotinyl-N'-(1-naphthyl)-ethylenediamine (BNEDA) and N-biotinyl-N'-dansyl-ethylenediamine (BDEDA) were used as the reference ligands and acceptors to streptavidin to test this new homogeneous competitive assay. Upon binding of an acceptor to streptavidin, there were the quench of streptavidin fluorescence at 340 nm and the characteristic fluorescence at 430 nm for BNEDA or at 525 nm for BDEDA. K(d) of BNEDA and BDEDA was obtained via competitive binding against biotin. By quantifying BNEDA fluorescence, K(d) of each tested nonfluorescent biotin derivative was consistent with that by quantifying streptavidin fluorescence using BNEDA or BDEDA as the acceptor. The overall coefficients of variation were about 10%. Therefore, this homogeneous competitive assay was effective and promising to high-throughput-screening.
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Affiliation(s)
- Yanling Xie
- Unit for Biotransformation and Protein Biotechnology, Chongqing Key Laboratory of Biochemical & Molecular Pharmacology, Chongqing Medical University, Chongqing 400016, China
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Plażuk D, Zakrzewski J, Salmain M. Biotin as acylating agent in the Friedel-Crafts reaction. Avidin affinity of biotinyl derivatives of ferrocene, ruthenocene and pyrene and fluorescence properties of 1-biotinylpyrene. Org Biomol Chem 2010; 9:408-17. [PMID: 20967359 DOI: 10.1039/c0ob00319k] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
(D)-Biotin was used for Friedel-Crafts acylation of electron-rich aromatic molecules--ferrocene, ruthenocene and pyrene. The reaction carried out in the presence of trifluoroacetic anhydride and trifluoromethanesulfonic acid afforded the corresponding biotinylarenes in moderate yields. These compounds, although lacking an amide bond, exhibited high affinity for avidin, with the ability to displace 2-(4'-hydroxyphenylazo)-benzoic acid (HABA) in its complex with avidin. Their affinity for avidin was determined by a solid-phase competitive enzymatic assay, which gave IC(50) values in the range of 33-58 nM (under the same conditions biotin showed IC(50) = 24 ± 7 nM). 1-Biotinylpyrene (1c) excited at 355 nm displayed fluorescence emission in aqueous solutions with λ(max) = 461 nm. The fluorescence maximum was shifted to 425 nm upon binding of 1c to avidin. Formation of the avidin-1c complex was also evidenced by quenching of the fluorescence from the protein tryptophan residues (342 nm) and appearance of the emission band of the avidin-bound 1c at 430 nm as a result of a Förster resonance energy transfer (FRET) phenomenon.
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Affiliation(s)
- Damian Plażuk
- Department of Organic Chemistry, University of Łódź, 91-403 Łódź, Tamka 12, Poland
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