151
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Martin AL, Bernas LM, Rutt BK, Foster PJ, Gillies ER. Enhanced Cell Uptake of Superparamagnetic Iron Oxide Nanoparticles Functionalized with Dendritic Guanidines. Bioconjug Chem 2008; 19:2375-84. [DOI: 10.1021/bc800209u] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Amanda L. Martin
- Department of Chemistry, Department of Chemical and Biochemical Engineering, Department of Medical Biophysics, and Imaging Research Laboratories—Robarts Research Institute, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 5B7, Canada
| | - Lisa M. Bernas
- Department of Chemistry, Department of Chemical and Biochemical Engineering, Department of Medical Biophysics, and Imaging Research Laboratories—Robarts Research Institute, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 5B7, Canada
| | - Brian K. Rutt
- Department of Chemistry, Department of Chemical and Biochemical Engineering, Department of Medical Biophysics, and Imaging Research Laboratories—Robarts Research Institute, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 5B7, Canada
| | - Paula J. Foster
- Department of Chemistry, Department of Chemical and Biochemical Engineering, Department of Medical Biophysics, and Imaging Research Laboratories—Robarts Research Institute, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 5B7, Canada
| | - Elizabeth R. Gillies
- Department of Chemistry, Department of Chemical and Biochemical Engineering, Department of Medical Biophysics, and Imaging Research Laboratories—Robarts Research Institute, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 5B7, Canada
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152
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Abstract
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An efficient route is reported to 5- and 6-carboxy-X-rhodamines (compounds 1 and 2) that contain multiple n-propylene or γ,γ-dimethylpropylene groups bridging terminal nitrogen atoms and the central xanthene core. Gram quantities of these dyes are synthesized from inexpensive starting materials. The isolated products are activated by selective transformation of the carboxylic acid group into N-hydroxysuccinimidyl esters in situ and then conjugated with an amino group of a molecule of interest.
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Affiliation(s)
- Md Jashim Uddin
- A. B. Hancock Jr. Memorial Laboratory for Cancer Research, Department of Biochemistry, Chemistry and Pharmacology, Vanderbilt Institute of Chemical Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146, USA
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153
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Deb SK, Davis B, Ben-Amotz D, Davisson VJ. Accurate concentration measurements using surface-enhanced Raman and deuterium exchanged dye pairs. APPLIED SPECTROSCOPY 2008; 62:1001-1007. [PMID: 18801239 DOI: 10.1366/000370208785793290] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Quantitative applications of surface-enhanced resonance Raman scattering (SERRS) are often limited by the reproducibility of SERRS intensities, given the difficulty of controlling analyte-substrate interactions and the associated local field enhancement. As demonstrated here, SERRS from dye molecules even within the same structural class that compete with similar substrates display distinct spectral intensities that are not proportional to analyte concentrations, which limits their use as internal standardization probes and/or for multiplex analysis. Recently, we demonstrated that isotopic variants of rhodamine 6G (R6G), namely R6G-d0 and R6G-d4, can be used for internal standards in SERRS experiments with a linear optical response from picomolar to micromolar concentrations (of total analytes). Here we extend these results by describing a straightforward method for obtaining isotopomeric pairs of other Raman active dyes by hydrogen-deuterium exchange conditions for substitution at electron rich aromatic heterocycles. Most of the known SERRS active probes can be converted into the corresponding isotopomeric molecule by this exchange method, which significantly expands the scope of the isotopic edited internal standard (IEIS) approach. The relative quantification using IEIS enables accurate, reproducible (residual standard deviation+/-2.2%) concentration measurements over a range of 200 pM to 2 microM. These studies enable easy access to a variety of isotopically substituted Raman active dyes and establish the generality of the methodology for quantitative SERRS measurements. For the first time, three rhodamine 6G isotopomers have been created and show distinct Raman spectra, demonstrating the principle of the approach for application as a multiplex technique in biomolecular detection/quantification.
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Affiliation(s)
- Shirshendu K Deb
- Department of Medicinal Chemistry and Molecular Pharmacology, Bindley Bioscience Center, Purdue University, West Lafayette, Indiana 47907, USA
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154
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Akita S, Umezawa N, Kato N, Higuchi T. Array-based fluorescence assay for serine/threonine kinases using specific chemical reaction. Bioorg Med Chem 2008; 16:7788-94. [PMID: 18656369 DOI: 10.1016/j.bmc.2008.07.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2008] [Revised: 06/30/2008] [Accepted: 07/01/2008] [Indexed: 11/16/2022]
Abstract
We report herein the development of an efficient fluorescence assay for serine/threonine kinases using a peptide array. Our approach is based on chemical reactions specific to phosphoserine and phosphothreonine residues, that is, base-mediated beta-elimination of the phosphate group and subsequent Michael addition of a thiol-containing fluorescent reagent. This procedure enables the covalent introduction of a fluorescent moiety into the phosphorylated peptide. Novel fluorescent reagents were designed for this purpose and synthesized. With these reagents, protein kinase A (PKA) and Akt-1 activities were readily detected. Our method can also be used to measure the activity of kinase inhibitors. This assay is expected to be widely applicable in kinase research.
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Affiliation(s)
- Shoji Akita
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya, Aichi 467-8603, Japan
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155
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Deb SK, Davis B, Knudsen GM, Gudihal R, Ben-Amotz D, Davisson VJ. Detection and relative quantification of proteins by surface enhanced Raman using isotopic labels. J Am Chem Soc 2008; 130:9624-5. [PMID: 18593116 PMCID: PMC2646756 DOI: 10.1021/ja800772p] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
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Accurate quantification of protein content and composition
has been achieved using isotope-edited surface enhanced resonance
Raman spectroscopy. Synthesis of isotopomeric Rhodamine dye-linked
bioconjugation reagents enabled direct labeling of surface lysines
on a variety of proteins. When separated in polyacrylamide gels and
stained with silver nanoparticles. The spectral signatures reflect
the expected statistical distribution of isotopomeric labels on the
labeled proteins in the gel matrix format without interference from
protein features.
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Affiliation(s)
- Shirshendu K Deb
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana 47907, USA
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156
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Finikova OS, Chen P, Ou Z, Kadish KM, Vinogradov SA. Dynamic Quenching of Porphyrin Triplet States by Two-Photon Absorbing Dyes: Towards Two-Photon-Enhanced Oxygen Nanosensors. J Photochem Photobiol A Chem 2008; 198:75-84. [PMID: 19030124 DOI: 10.1016/j.jphotochem.2008.02.020] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Two-photon-enhanced dendritic nanoprobes are being developed for two-photon (2P) laser scanning microscopy of oxygen [1]. In these molecular constructs, phosphorescence of metalloporphyrins is coupled to two-photon absorption (2PA) of electronically separate antenna dyes via intramolecular Förster-type resonance energy transfer (FRET). In the originally developed probes, competing electron transfer (ET) between the antennae and the long-lived triplet states of metalloporphyrins partially quenched the phosphorescence, reducing the probe's sensitivity and dynamic range. The rate of such ET can be reduced by tuning the redox potentials of the chromophores. In order to identify the optimal metalloporphyrin-2P antenna pairs, we performed screening of several phosphorescent Pt porphyrins (FRET acceptors) and 2P dyes (FRET donors) using dynamic quenching of phosphorescence. Phosphorescence lifetimes of Pt porphyrins were measured as a function of the dye concentration in organic solutions. The obtained Stern-Volmer quenching constants were correlated with the corresponding ET driving forces (DeltaG(ET)), calculated using the Rehm-Weller equation. FRET-pairs with minimal quenching rates were identified. The developed approach allows convenient screening of candidate-compounds for covalent assembly of 2P-enhanced triplet nanodevices. Systematic electrochemical measurements in a series of Pt porphyrins with varying peripheral substitution and conjugation pathways are presented.
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Affiliation(s)
- Olga S Finikova
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA 19104
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157
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Boyarskiy VP, Belov VN, Medda R, Hein B, Bossi M, Hell SW. Photostable, amino reactive and water-soluble fluorescent labels based on sulfonated rhodamine with a rigidized xanthene fragment. Chemistry 2008; 14:1784-92. [PMID: 18058955 DOI: 10.1002/chem.200701058] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Highly water soluble fluorescent dyes were synthesized and transformed into new amino reactive fluorescent labels for biological microscopy. To this end, rhodamine 8 (prepared from 7-hydroxy-1,2,3,4-tetrahydroquinoline (7) and phthalic anhydride in 85 % aq. H(3)PO(4)) was sulfonated with 30 % SO(3) in H(2)SO(4) and afforded the water soluble disulfonic acid 3 a (64 %). Amidation of the carboxy group in 3 a with 2-(methylamino)ethanol in the presence of O-(7-azabenzotriazol-1-yl)-N,N,N',N'-tetramethyluroniumPF(6) (-) (HATU) led to alcohol 3 b (66 %), which was transformed into the amino reactive mixed carbonate 3 d with di(N-succinimidyl)carbonate and Et(3)N. Reaction of the carboxy group in 3 a with MeNH(CH(2))(2)CO(2)Me and N,N,N',N'-tetramethyl-O-(N-succinimidyl)-uroniumBF(4) (-) (TSTU) yielded methyl ester 13. After saponification of the aliphatic carboxy group in 13, the compound was converted into NHS-ester 3 e (using HATU and Et(3)N). Heating of 7 with trimellitic anhydride in H(3)PO(4) gave a mixture of dicarboxylic acids 14 and 15 (1:1). Regioisomer 15 was isolated, sulfonated with 30 % SO(3) in H(2)SO(4), and disulfonic acid 3 f was used for the synthesis of the mono NHS-ester 3 g, in which the sterically unhindered carboxy group was selectively activated (with N-hydroxysuccinimide, HATU, and Et(3)N). The sulfonated rhodamines 3 b, c and f are soluble in water (up to 0.1 M), have excellent photostabilities and large fluorescence quantum yields. Subdiffraction resolution images of tubulin filaments of mammalian cells stained with these dyes illustrate their applicability as labels for stimulated emission depletion microscopy and other fluorescence techniques.
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Affiliation(s)
- Vadim P Boyarskiy
- Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
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158
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Zheng H, Shang GQ, Yang SY, Gao X, Xu JG. Fluorogenic and Chromogenic Rhodamine Spirolactam Based Probe for Nitric Oxide by Spiro Ring Opening Reaction. Org Lett 2008; 10:2357-60. [DOI: 10.1021/ol800206x] [Citation(s) in RCA: 125] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Hong Zheng
- Key Laboratory of Analytical Sciences, Ministry of Education, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Gui-Qin Shang
- Key Laboratory of Analytical Sciences, Ministry of Education, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Shi-Yao Yang
- Key Laboratory of Analytical Sciences, Ministry of Education, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Xia Gao
- Key Laboratory of Analytical Sciences, Ministry of Education, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Jin-Gou Xu
- Key Laboratory of Analytical Sciences, Ministry of Education, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
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159
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A Novel Hg2+ Selective Ratiometric Fluorescent Chemodosimeter Based on an Intramolecular FRET Mechanism. J Fluoresc 2008; 18:1187-92. [DOI: 10.1007/s10895-008-0365-7] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2008] [Accepted: 03/14/2008] [Indexed: 10/22/2022]
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160
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Poole LB, Klomsiri C, Knaggs SA, Furdui CM, Nelson KJ, Thomas MJ, Fetrow JS, Daniel LW, King SB. Fluorescent and affinity-based tools to detect cysteine sulfenic acid formation in proteins. Bioconjug Chem 2007; 18:2004-17. [PMID: 18030992 DOI: 10.1021/bc700257a] [Citation(s) in RCA: 141] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cysteine sulfenic acid formation in proteins results from the oxidative modification of susceptible cysteine residues by hydrogen peroxide, alkyl hydroperoxides, and peroxynitrite. This species represents a biologically significant modification occurring during oxidant signaling or oxidative stress, and it can modulate protein function. Most methods to identify such oxidatively modified proteins rely on monitoring the loss of one or more thiol group(s) or on selective labeling of nascent thiol groups following reduction of oxidized proteins. Our previous work reported the direct labeling of these chemically distinct modifications with a dimedone analogue, 1,3-cyclohexadione, to which a linker and functional group (an alcohol) had been added; further addition of a fluorescent isatoic acid or methoxycoumarin reporter allowed detection of the incorporated tag by fluorescence techniques ( Poole, L. B., Zeng, B. B., Knaggs, S. A., Yakubu, M., and King, S. B. ( 2005) Synthesis of chemical probes to map sulfenic acid modifications on proteins. Bioconjugate Chem . 16, 1624-1628 ). We have now expanded our arsenal of tagging reagents to include two fluorescein-, two rhodamine-, and three biotin-conjugated probes based on the original approach. The new tools provide readily detectable fluorescent and affinity probes to identify sulfenic acid modifications in proteins and have been used in subsequent mass spectrometric analyses to confirm covalent attachment of the conjugates and directly determine the site of modification.
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Affiliation(s)
- Leslie B Poole
- Department of Biochemistry and Section on Molecular Medicine, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA.
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161
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Fölling J, Belov V, Kunetsky R, Medda R, Schönle A, Egner A, Eggeling C, Bossi M, Hell SW. Photochromic rhodamines provide nanoscopy with optical sectioning. Angew Chem Int Ed Engl 2007; 46:6266-70. [PMID: 17640007 DOI: 10.1002/anie.200702167] [Citation(s) in RCA: 208] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- J Fölling
- Abteilung NanoBiophotonik, Max-Planck-Institut für Biophysikalische Chemie, Am Fassberg 11, 37077 Göttingen, Germany
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162
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Füssl A, Schleifenbaum A, Göritz M, Riddell A, Schultz C, Krämer R. Cellular uptake of PNA--terpyridine conjugates and its enhancement by Zn2+ ions. J Am Chem Soc 2007; 128:5986-7. [PMID: 16669638 DOI: 10.1021/ja0571139] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Conjugation of usually impermeable peptide nucleic acids (PNA) to the chelator 2,2':6',2' '-terpyridine strongly promotes cellular and nuclear uptake by cultured HeLa cells. Cellular accumulation is further enhanced in the presence of extracellular Zn2+.
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Affiliation(s)
- Andreas Füssl
- European Molecular Biology Laboratory (EMBL) Heidelberg, Meyerhofstrasse 1, 69117 Heidelberg, Germany
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163
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Fölling J, Belov V, Kunetsky R, Medda R, Schönle A, Egner A, Eggeling C, Bossi M, Hell S. Photochromic Rhodamines Provide Nanoscopy with Optical Sectioning. Angew Chem Int Ed Engl 2007. [DOI: 10.1002/ange.200702167] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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164
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Finikova OS, Troxler T, Senes A, DeGrado WF, Hochstrasser RM, Vinogradov SA. Energy and electron transfer in enhanced two-photon-absorbing systems with triplet cores. J Phys Chem A 2007; 111:6977-90. [PMID: 17608457 PMCID: PMC2441487 DOI: 10.1021/jp071586f] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Enhanced two-photon-absorbing (2PA) systems with triplet cores are currently under scrutiny for several biomedical applications, including photodynamic therapy (PDT) and two-photon microscopy of oxygen. The performance of so far developed molecules, however, is substantially below expected. In this study we take a detailed look at the processes occurring in these systems and propose ways to improve their performance. We focus on the interchromophore distance tuning as a means for optimization of two-photon sensors for oxygen. In these constructs, energy transfer from several 2PA chromophores is used to enhance the effective 2PA cross section of phosphorescent metalloporphyrins. Previous studies have indicated that intramolecular electron transfer (ET) can act as an effective quencher of phosphorescence, decreasing the overall sensor efficiency. We studied the interplay between 2PA, energy transfer, electron transfer, and phosphorescence emission using Rhodamine B-Pt tetrabenzoporphyrin (RhB-PtTBP) adducts as model compounds. 2PA cross sections (sigma2) of tetrabenzoporphyrins (TBPs) are in the range of several tens of GM units (near 800 nm), making TBPs superior 2PA chromophores compared to regular porphyrins (sigma2 values typically 1-2 GM). Relatively large 2PA cross sections of rhodamines (about 200 GM in 800-850 nm range) and their high photostabilities make them good candidates as 2PA antennae. Fluorescence of Rhodamine B (lambda(fl) = 590 nm, phi(fl) = 0.5 in EtOH) overlaps with the Q-band of phosphorescent PtTBP (lambda(abs) = 615 nm, epsilon = 98 000 M(-1) cm(-1), phi(p) approximately 0.1), suggesting that a significant amplification of the 2PA-induced phosphorescence via fluorescence resonance energy transfer (FRET) might occur. However, most of the excitation energy in RhB-PtTBP assemblies is consumed in several intramolecular ET processes. By installing rigid nonconducting decaproline spacers (Pro10) between RhB and PtTBP, the intramolecular ETs were suppressed, while the chromophores were kept within the Förster r0 distance in order to maintain high FRET efficiency. The resulting assemblies exhibit linear amplification of their 2PA-induced phosphorescence upon increase in the number of 2PA antenna chromophores and show high oxygen sensitivity. We also have found that PtTBPs possess unexpectedly strong forbidden S0 --> T1 bands (lambda(max) = 762 nm, epsilon = 120 M-1 cm-1). The latter may overlap with the laser spectrum and lead to unwanted linear excitation.
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Affiliation(s)
- Olga S Finikova
- Departments of Biochemistry and Biophysics and Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA
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165
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Chang PV, Prescher JA, Hangauer MJ, Bertozzi CR. Imaging cell surface glycans with bioorthogonal chemical reporters. J Am Chem Soc 2007; 129:8400-1. [PMID: 17579403 PMCID: PMC2535820 DOI: 10.1021/ja070238o] [Citation(s) in RCA: 163] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Pamela V Chang
- Department of Chemistry, Howard Hughes Medical Institute, University of California, Berkeley, California 94720, USA
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166
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167
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Li B, Martin AL, Gillies ER. Multivalent polymer vesicles via surface functionalization. Chem Commun (Camb) 2007:5217-9. [DOI: 10.1039/b713569f] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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168
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Bossi M, Belov V, Polyakova S, Hell SW. Reversible rot fluoreszierende molekulare Schalter. Angew Chem Int Ed Engl 2006. [DOI: 10.1002/ange.200602591] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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169
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Bossi M, Belov V, Polyakova S, Hell SW. Reversible Red Fluorescent Molecular Switches. Angew Chem Int Ed Engl 2006; 45:7462-5. [PMID: 17042053 DOI: 10.1002/anie.200602591] [Citation(s) in RCA: 147] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Mariano Bossi
- Department of Nanobiophotonics, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
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170
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Burchak ON, Mugherli L, Chatelain F, Balakirev MY. Fluorescein-based amino acids for solid phase synthesis of fluorogenic protease substrates. Bioorg Med Chem 2006; 14:2559-68. [PMID: 16380261 DOI: 10.1016/j.bmc.2005.11.037] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2005] [Revised: 10/05/2005] [Accepted: 11/18/2005] [Indexed: 11/28/2022]
Abstract
An efficient synthesis of new type fluorescent amino acids is described. The Fmoc-protected dyes can be prepared in a four-step procedure with approximately 30% overall yield from aminofluoresceins and other inexpensive commercially available precursors. The dyes are much more photostable compared to fluorescein and exhibit constant pH-independent fluorescence that is advantageous in biological applications. The Fmoc-protected fluorescent amino acids are ready for use in solid phase peptide synthesis. As a proof of concept, a fluorogenic papain substrate was synthesized and employed for on-bead detection of the protease activity. By using a novel technique for quantitative analysis of bead fluorescence, a approximately 2.7-fold increase in mean bead brightness was measured and was attributed to substrate cleavage by papain. The new type fluorescent amino acids seem to be a promising tool for the synthesis of fluorescent peptide ligands and fluorogenic protease substrates.
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Affiliation(s)
- Olga N Burchak
- Laboratoire Biopuces, Département Réponse et Dynamique Cellulaires, Commissariat à l'Energie Atomique, 17 rue des Martyrs, 38054 Grenoble, France
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171
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Pullela PK, Chiku T, Carvan MJ, Sem DS. Fluorescence-based detection of thiols in vitro and in vivo using dithiol probes. Anal Biochem 2006; 352:265-73. [PMID: 16527239 DOI: 10.1016/j.ab.2006.01.047] [Citation(s) in RCA: 126] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2005] [Revised: 01/24/2006] [Accepted: 01/27/2006] [Indexed: 10/25/2022]
Abstract
Thiols play a central role in maintaining biological homeostasis. Their levels can change dramatically in response to oxidative stress associated with toxic insults, bacterial infection, and disease. Therefore, a reagent that can monitor thiol levels both in vitro and in vivo would be useful for assays and as a biomarker. Such a reagent should (i) be selective for thiols, (ii) be able to penetrate cell walls, and (iii) have a low reduction potential so as not to create oxidative stress in a cell. We have developed such a fluorescent reagent (DSSA) based on a dithiol linker: (i) the use of a dithiol linker makes it selective for thiols; (ii) the use of fluorophores that populate neutral states at physiological pH improves cell wall penetration; and (iii) because of the reagent's low reduction potential (-0.60 V), it will not stress cells oxidatively. For example, 5 microM of reagent is responsive to changes in glutathione levels in the physiologically relevant range of 1 to 10mM, yet this would oxidize less than 1% of cellular glutathione. In Escherichia coli, decreased thiol levels were detected in cells deficient in glutathione synthesis. In zebrafish embryos, the DSSA reagent permitted detection of unusually high thiol levels in the zebrafish chorion.
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Affiliation(s)
- Phani Kumar Pullela
- Chemical Proteomics Facility at Marquette, Department of Chemistry, Marquette University, Milwaukee, WI 53201, USA
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172
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Nicolas J, San Miguel V, Mantovani G, Haddleton DM. Fluorescently tagged polymer bioconjugates from protein derived macroinitiators. Chem Commun (Camb) 2006:4697-9. [PMID: 17109040 DOI: 10.1039/b609935a] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
BSA and lysozyme have been transformed into macroinitiators for living radical polymerisation and used to produce well-defined bioconjugates which can be fluorescently labelled providing a versatile strategy for the preparation of bioconjugates which is complementary to traditional PEGylation.
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Affiliation(s)
- Julien Nicolas
- Department of Chemistry, University of Warwick, Coventry, UKCV4 7AL
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173
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Laughlin ST, Agard NJ, Baskin JM, Carrico IS, Chang PV, Ganguli AS, Hangauer MJ, Lo A, Prescher JA, Bertozzi CR. Metabolic Labeling of Glycans with Azido Sugars for Visualization and Glycoproteomics. Methods Enzymol 2006; 415:230-50. [PMID: 17116478 DOI: 10.1016/s0076-6879(06)15015-6] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The staggering complexity of glycans renders their analysis extraordinarily difficult, particularly in living systems. A recently developed technology, termed metabolic oligosaccharide engineering, enables glycan labeling with probes for visualization in cells and living animals, and enrichment of specific glycoconjugate types for proteomic analysis. This technology involves metabolic labeling of glycans with a specifically reactive, abiotic functional group, the azide. Azido sugars are fed to cells and integrated by the glycan biosynthetic machinery into various glycoconjugates. The azido sugars are then covalently tagged, either ex vivo or in vivo, using one of two azide-specific chemistries: the Staudinger ligation, or the strain-promoted [3+2] cycloaddition. These reactions can be used to tag glycans with imaging probes or epitope tags, thus enabling the visualization or enrichment of glycoconjugates. Applications to noninvasive imaging and glycoproteomic analyses are discussed.
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Affiliation(s)
- Scott T Laughlin
- Department of Chemistry, Howard Hughes Medical Institute, University of California, Berkeley, USA
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174
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Yang YK, Yook KJ, Tae J. A Rhodamine-Based Fluorescent and Colorimetric Chemodosimeter for the Rapid Detection of Hg2+Ions in Aqueous Media. J Am Chem Soc 2005; 127:16760-1. [PMID: 16316202 DOI: 10.1021/ja054855t] [Citation(s) in RCA: 779] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A rhodamine-based fluorescent and colorimetric chemodosimeter for the rapid detection of Hg2+ ions in aqueous media was developed. The system, which utilizes an irreversible Hg2+-promoted oxadiazole forming reaction, responds instantaneously at room temperature in a 1:1 stoichiometric manner to the amount of Hg2+. The selectivity of this system for Hg2+ over other metal ions is remarkably high, and its sensitivity is below 2 ppb in aqueous solutions.
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175
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Wong LS, Birembaut F, Brocklesby WS, Frey JG, Bradley M. Resin Bead Micro-UV−Visible Absorption Spectroscopy. Anal Chem 2005; 77:2247-51. [PMID: 15801760 DOI: 10.1021/ac049319i] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The construction and design of a microscope coupled with a miniature UV-vis spectrometer is described. This was applied to the study of dyes linked to solid supports and displayed good correlation in spectral shape and lambda(max) values when compared to the dyes in solution, as well as showing a linear relationship between dye loading and UV-vis absorbance. The spectral profiles of these dyes at various pH's were measured and used to determine the pK(a) of the dyes on the beads, which were compared with the pK(a) values of the dyes in solution, thus enabling the dye-loaded beads to act as pH sensors.
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Affiliation(s)
- Lu Shin Wong
- School of Chemistry, University of Edinburgh, Edinburgh EH9 3JJ, UK
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176
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Schlick TL, Ding Z, Kovacs EW, Francis MB. Dual-Surface Modification of the Tobacco Mosaic Virus. J Am Chem Soc 2005; 127:3718-23. [PMID: 15771505 DOI: 10.1021/ja046239n] [Citation(s) in RCA: 396] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The protein shell of the tobacco mosaic virus (TMV) provides a robust and practical tubelike scaffold for the preparation of nanoscale materials. To expand the range of applications for which the capsid can be used, two synthetic strategies have been developed for the attachment of new functionality to either the exterior or the interior surface of the virus. The first of these is accomplished using a highly efficient diazonium coupling/oxime formation sequence, which installs >2000 copies of a material component on the capsid exterior. Alternatively, the inner cavity of the tube can be modified by attaching amines to glutamic acid side chains through a carbodiimide coupling reaction. Both of these reactions have been demonstrated for a series of substrates, including biotin, chromophores, and crown ethers. Through the attachment of PEG polymers to the capsid exterior, organic-soluble TMV rods have been prepared. Finally, the orthogonality of these reactions has been demonstrated by installing different functional groups on the exterior and interior surfaces of the same capsid assemblies.
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Affiliation(s)
- Tara L Schlick
- Department of Chemistry, University of California, Berkeley, California 94720-1460, USA
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177
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Joshi NS, Whitaker LR, Francis MB. A Three-Component Mannich-Type Reaction for Selective Tyrosine Bioconjugation. J Am Chem Soc 2004; 126:15942-3. [PMID: 15584710 DOI: 10.1021/ja0439017] [Citation(s) in RCA: 248] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A new selective bioconjugation reaction is described for the modification of tyrosine residues on protein substrates. The reaction uses imines formed in situ from aldehydes and electron-rich anilines to modify phenolic side chains through a Mannich-type electrophilic aromatic substitution pathway. The reaction takes place under mild pH and temperature conditions and can modify protein substrates at concentrations as low as 20 muM. Using an efficient fluorescence-based assay, we demonstrated the reaction using a number of aldehydes and protein targets. Importantly, proteins lacking surface-accessible tyrosines remained unmodified. It was also demonstrated that enzymatic activity is preserved under the mild reaction conditions. This strategy represents one of the first carbon-carbon bond-forming reactions for protein modification and provides an important complement to more commonly used lysine- and cysteine-based methods.
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Affiliation(s)
- Neel S Joshi
- Department of Chemistry, University of California, Berkeley, California 94720-1460, USA
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