1
|
Berg C, Busch S, Alawiyah MD, Finger M, Ihling N, Paquet-Durand O, Hitzmann B, Büchs J. Advancing 2D fluorescence online monitoring in microtiter plates by separating scattered light and fluorescence measurement, using a tunable emission monochromator. Biotechnol Bioeng 2023; 120:2925-2939. [PMID: 37350126 DOI: 10.1002/bit.28474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 06/07/2023] [Accepted: 06/08/2023] [Indexed: 06/24/2023]
Abstract
Online fluorescence monitoring has become a key technology in modern bioprocess development, as it provides in-depth process knowledge at comparably low costs. In particular, the technology is widely established for high-throughput microbioreactor cultivation systems, due to its noninvasive character. For microtiter plates, previously also multi-wavelength 2D fluorescence monitoring was developed. To overcome an observed limitation of fluorescence sensitivity, this study presents a modified spectroscopic setup, including a tunable emission monochromator. The new optical component enables the separation of the scattered and fluorescent light measurements, which allows for the adjustment of integration times of the charge-coupled device detector. The resulting increased fluorescence sensitivity positively affected the performance of principal component analysis for spectral data of Escherichia coli batch cultivation experiments with varying sorbitol concentration supplementation. In direct comparison with spectral data recorded at short integration times, more biologically consistent signal dynamics were calculated. Furthermore, during partial least square regression for E. coli cultivation experiments with varying glucose concentrations, improved modeling performance was observed. Especially, for the growth-uncoupled acetate concentration, a considerable improvement of the root-mean-square error from 0.25 to 0.17 g/L was achieved. In conclusion, the modified setup represents another important step in advancing 2D fluorescence monitoring in microtiter plates.
Collapse
Affiliation(s)
- Christoph Berg
- AVT-Aachener Verfahrenstechnik, Biochemical Engineering, RWTH Aachen University, Aachen, Germany
| | - Selma Busch
- AVT-Aachener Verfahrenstechnik, Biochemical Engineering, RWTH Aachen University, Aachen, Germany
| | - Muthia Dewi Alawiyah
- AVT-Aachener Verfahrenstechnik, Biochemical Engineering, RWTH Aachen University, Aachen, Germany
| | - Maurice Finger
- AVT-Aachener Verfahrenstechnik, Biochemical Engineering, RWTH Aachen University, Aachen, Germany
| | - Nina Ihling
- AVT-Aachener Verfahrenstechnik, Biochemical Engineering, RWTH Aachen University, Aachen, Germany
| | - Olivier Paquet-Durand
- Department of Process Analytics & Cereal Science, Institute for Food Science and Biotechnology, University of Hohenheim, Stuttgart, Germany
| | - Bernd Hitzmann
- Department of Process Analytics & Cereal Science, Institute for Food Science and Biotechnology, University of Hohenheim, Stuttgart, Germany
| | - Jochen Büchs
- AVT-Aachener Verfahrenstechnik, Biochemical Engineering, RWTH Aachen University, Aachen, Germany
| |
Collapse
|
2
|
|
3
|
Visualization and fluorescence spectroscopy of fingerprints on glass slide using combined 405 nm laser and phase contrast microscope. J Vis (Tokyo) 2021. [DOI: 10.1007/s12650-021-00745-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
4
|
Obregón-Mendoza MA, Arias-Olguín II, Estévez-Carmona MM, Meza-Morales W, Alvarez-Ricardo Y, Toscano RA, Arenas-Huertero F, Cassani J, Enríquez RG. Non-Cytotoxic Dibenzyl and Difluoroborate Curcuminoid Fluorophores Allow Visualization of Nucleus or Cytoplasm in Bioimaging. Molecules 2020; 25:molecules25143205. [PMID: 32674349 PMCID: PMC7397183 DOI: 10.3390/molecules25143205] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 07/10/2020] [Accepted: 07/11/2020] [Indexed: 01/27/2023] Open
Abstract
Curcumin, the most important secondary metabolite isolated from Curcuma longa, is known for its numerous purported therapeutic properties and as a natural dye. Herein, based on curcumin's intrinsic fluorescence, a search for improved curcumin-based fluorophores was conducted. Within the set of semi-synthetic curcumin derivatives i.e. mono (1), di (2), tri (3), tetra (4) benzylated and dibenzyl-fluoroborate (5), the fluorescence properties of 2 and 5 in solution outstood with a two-fold quantum yield compared to curcumin. Furthermore, all benzylated derivatives showed a favorable minimal cytotoxic activity upon screening at 25 μM against human cancer and non-tumoral COS-7 cell lines, with a reduction of its cytotoxic effect related to the degree of substitution. Fluorophores 2 and 5 are versatile bioimaging tools, as revealed by Confocal Fluorescence Microscopy (CFM), and showed permeation of living cell membranes of astrocytes and astrocytomas. When 2 is excited with a 405- (blue) or 543-nm (green) laser, it is possible to exclusively and intensively visualize the nucleus. However, the fluorescence emission fades as the laser wavelength moves towards the red region. In comparison, 5 allows selective visualization of cytoplasm when a 560-nm laser is used, showing emission in the NIR region, while it is possible to exclusively observe the nucleus at the blue region with a 405-nm laser.
Collapse
Affiliation(s)
- Marco A. Obregón-Mendoza
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, Ciudad de México 04510, Mexico; (M.A.O.-M.); (I.I.A.-O.); (W.M.-M.); (Y.A.-R.); (R.A.T.)
| | - Imilla I. Arias-Olguín
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, Ciudad de México 04510, Mexico; (M.A.O.-M.); (I.I.A.-O.); (W.M.-M.); (Y.A.-R.); (R.A.T.)
| | - M. Mirian Estévez-Carmona
- Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Wilfrido Massieu SN, Ciudad de México 07738, Mexico;
| | - William Meza-Morales
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, Ciudad de México 04510, Mexico; (M.A.O.-M.); (I.I.A.-O.); (W.M.-M.); (Y.A.-R.); (R.A.T.)
| | - Yair Alvarez-Ricardo
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, Ciudad de México 04510, Mexico; (M.A.O.-M.); (I.I.A.-O.); (W.M.-M.); (Y.A.-R.); (R.A.T.)
| | - Rubén A. Toscano
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, Ciudad de México 04510, Mexico; (M.A.O.-M.); (I.I.A.-O.); (W.M.-M.); (Y.A.-R.); (R.A.T.)
| | - Francisco Arenas-Huertero
- Laboratorio de Investigación en Patología Experimental, Hospital Infantil de México Federico Gómez, Ciudad de México 06720, Mexico;
| | - Julia Cassani
- Departamento de Sistemas Biológicos, Universidad Autónoma Metropolitana, Unidad Xochimilco, Ciudad de México 04960, Mexico;
| | - Raúl G. Enríquez
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, Ciudad de México 04510, Mexico; (M.A.O.-M.); (I.I.A.-O.); (W.M.-M.); (Y.A.-R.); (R.A.T.)
- Correspondence: ; Tel.: +52-55-5622-4404
| |
Collapse
|
5
|
Brunner M, Brosig P, Losing M, Kunzelmann M, Calvet A, Stiefel F, Bechmann J, Unsoeld A, Schaub J. Towards robust cell culture processes - Unraveling the impact of media preparation by spectroscopic online monitoring. Eng Life Sci 2020; 19:666-680. [PMID: 32624960 PMCID: PMC6999248 DOI: 10.1002/elsc.201900050] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 07/12/2019] [Accepted: 07/31/2019] [Indexed: 11/09/2022] Open
Abstract
Biopharmaceutical manufacturing processes can be affected by variability in cell culture media, e.g. caused by raw material impurities. Although efforts have been made in industry and academia to characterize cell culture media and raw materials with advanced analytics, the process of industrial cell culture media preparation itself has not been reported so far. Within this publication, we first compare mid-infrared and two-dimensional fluorescence spectroscopy with respect to their suitability as online monitoring tools during cell culture media preparation, followed by a thorough assessment of the impact of preparation parameters on media quality. Through the application of spectroscopic methods, we can show that media variability and its corresponding root cause can be detected online during the preparation process. This methodology is a powerful tool to avoid batch failure and is a valuable technology for media troubleshooting activities. Moreover, in a design of experiments approach, including additional liquid chromatography-mass spectrometry analytics, it is shown that variable preparation parameters such as temperature, power input and preparation time can have a strong impact on the physico-chemical composition of the media. The effect on cell culture process performance and product quality in subsequent fed-batch processes was also investigated. The presented results reveal the need for online spectroscopic methods during the preparation process and show that media variability can already be introduced by variation in media preparation parameters, with a potential impact on scale-up to a commercial manufacturing process.
Collapse
Affiliation(s)
- Matthias Brunner
- Bioprocess Development Biologicals Boehringer Ingelheim Pharma GmbH & Co. KG Biberach Germany
| | - Philipp Brosig
- Bioprocess Development Biologicals Boehringer Ingelheim Pharma GmbH & Co. KG Biberach Germany
| | - Monika Losing
- Bioprocess Development Biologicals Boehringer Ingelheim Pharma GmbH & Co. KG Biberach Germany
| | - Marco Kunzelmann
- Analytical Development Biologicals Boehringer Ingelheim Pharma GmbH & Co. KG Biberach Germany
| | - Amandine Calvet
- Bioprocess Development Biologicals Boehringer Ingelheim Pharma GmbH & Co. KG Biberach Germany
| | - Fabian Stiefel
- Bioprocess Development Biologicals Boehringer Ingelheim Pharma GmbH & Co. KG Biberach Germany
| | - Jan Bechmann
- Bioprocess Development Biologicals Boehringer Ingelheim Pharma GmbH & Co. KG Biberach Germany
| | - Andreas Unsoeld
- Bioprocess Development Biologicals Boehringer Ingelheim Pharma GmbH & Co. KG Biberach Germany
| | - Jochen Schaub
- Bioprocess Development Biologicals Boehringer Ingelheim Pharma GmbH & Co. KG Biberach Germany
| |
Collapse
|
6
|
Khokhar V, Guha A, Dhawan S, Trivedi S, Haridas V, Pandey S. Spectroscopic investigation of linear and branched tryptophan-containing peptides. J Photochem Photobiol A Chem 2019. [DOI: 10.1016/j.jphotochem.2018.11.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
7
|
Groza RC, Calvet A, Ryder AG. A fluorescence anisotropy method for measuring protein concentration in complex cell culture media. Anal Chim Acta 2014; 821:54-61. [PMID: 24703214 DOI: 10.1016/j.aca.2014.03.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 03/06/2014] [Accepted: 03/07/2014] [Indexed: 01/09/2023]
Abstract
The rapid, quantitative analysis of the complex cell culture media used in biopharmaceutical manufacturing is of critical importance. Requirements for cell culture media composition profiling, or changes in specific analyte concentrations (e.g. amino acids in the media or product protein in the bioprocess broth) often necessitate the use of complicated analytical methods and extensive sample handling. Rapid spectroscopic methods like multi-dimensional fluorescence (MDF) spectroscopy have been successfully applied for the routine determination of compositional changes in cell culture media and bioprocess broths. Quantifying macromolecules in cell culture media is a specific challenge as there is a need to implement measurements rapidly on the prepared media. However, the use of standard fluorescence spectroscopy is complicated by the emission overlap from many media components. Here, we demonstrate how combining anisotropy measurements with standard total synchronous fluorescence spectroscopy (TSFS) provides a rapid, accurate quantitation method for cell culture media. Anisotropy provides emission resolution between large and small fluorophores while TSFS provides a robust measurement space. Model cell culture media was prepared using yeastolate (2.5 mg mL(-1)) spiked with bovine serum albumin (0 to 5 mg mL(-1)). Using this method, protein emission is clearly discriminated from background yeastolate emission, allowing for accurate bovine serum albumin (BSA) quantification over a 0.1 to 4.0 mg mL(-1) range with a limit of detection (LOD) of 13.8 μg mL(-1).
Collapse
Affiliation(s)
- Radu Constantin Groza
- Nanoscale Biophotonics Laboratory, School of Chemistry, National University of Ireland, Galway, Ireland
| | - Amandine Calvet
- Nanoscale Biophotonics Laboratory, School of Chemistry, National University of Ireland, Galway, Ireland
| | - Alan G Ryder
- Nanoscale Biophotonics Laboratory, School of Chemistry, National University of Ireland, Galway, Ireland.
| |
Collapse
|
8
|
Hill SC, Pan YL, Williamson C, Santarpia JL, Hill HH. Fluorescence of bioaerosols: mathematical model including primary fluorescing and absorbing molecules in bacteria. OPTICS EXPRESS 2013; 21:22285-313. [PMID: 24104120 DOI: 10.1364/oe.21.022285] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
This paper describes a mathematical model of fluorescent biological particles composed of bacteria, viruses, or proteins. The fluorescent and/or light absorbing molecules included in the model are amino acids (tryptophan, etc.); nucleic acids (DNA, RNA, etc.); coenzymes (nicotinamide adenine dinucleotides, flavins, and vitamins B₆ and K and variants of these); and dipicolinates. The concentrations, absorptivities, and fluorescence quantum yields are estimated from the literature, often with large uncertainties. The bioparticles in the model are spherical and homogeneous. Calculated fluorescence cross sections for particles excited at 266, 280, and 355 nm are compared with measured values from the literature for several bacteria, bacterial spores and albumins. The calculated 266- and 280-nm excited fluorescence is within a factor of 3.2 of the measurements for the vegetative cells and proteins, but overestimates the fluorescence of spores by a factor of 10 or more. This is the first reported modeling of the fluorescence of bioaerosols in which the primary fluorophores and absorbing molecules are included.
Collapse
|
9
|
Abstract
The C-termini of G protein-coupled receptors (GPCRs) interact with specific kinases and arrestins in an agonist-dependent manner suggesting that conformational changes induced by ligand binding within the transmembrane domains are transmitted to the C-terminus. Förster resonance energy transfer (FRET) can be used to monitor changes in distance between two protein domains if each site can be specifically and efficiently labeled with a donor or acceptor fluorophore. In order to probe GPCR conformational changes, we have developed a FRET technique that uses site-specific donor and acceptor fluorophores introduced by two orthogonal labeling chemistries. Using this strategy, we examined ligand-induced changes in the distance between two labeled sites in the beta(2) adrenoceptor (beta(2)-AR), a well-characterized GPCR model system. The donor fluorophore, LumioGreen, is chelated by a CCPGCC motif [Fluorescein Arsenical Helix or Hairpin binder (FlAsH) site] introduced through mutagenesis. The acceptor fluorophore, Alexa Fluor 568, is attached to a single reactive cysteine (C265). FRET analyses revealed that the average distance between the intracellular end of transmembrane helix (TM) six and the C-terminus of the beta(2)-AR is 62 A. This relatively large distance suggests that the C-terminus is extended and unstructured. Nevertheless, ligand-specific conformational changes were observed (1). The results provide new insight into the structure of the beta(2)-AR C-terminus and ligand-induced conformational changes that may be relevant to arrestin interactions. The FRET labeling technique described herein can be applied to many GPCRs (and other membrane proteins) and is suitable for conformational studies of domains other than the C-terminus.
Collapse
|
10
|
Granier S, Kim S, Shafer AM, Ratnala VRP, Fung JJ, Zare RN, Kobilka B. Structure and conformational changes in the C-terminal domain of the beta2-adrenoceptor: insights from fluorescence resonance energy transfer studies. J Biol Chem 2007; 282:13895-905. [PMID: 17347144 DOI: 10.1074/jbc.m611904200] [Citation(s) in RCA: 134] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The C terminus of the beta(2)-adrenoceptor (AR) interacts with G protein-coupled receptor kinases and arrestins in an agonist-dependent manner, suggesting that conformational changes induced by ligands in the transmembrane domains are transmitted to the C terminus. We used fluorescence resonance energy transfer (FRET) to examine ligand-induced structural changes in the distance between two positions on the beta(2)-AR C terminus and cysteine 265 (Cys-265) at the cytoplasmic end of transmembrane domain 6. The donor fluorophore FlAsH (Fluorescein Arsenical Helix binder) was attached to a CCPGCC motif introduced at position 351-356 in the proximal C terminus or at the distal C terminus. An acceptor fluorophore, Alexa Fluor 568, was attached to Cys-265. FRET analyses revealed that the average distances between Cys-265 and the proximal and distal FlAsH sites were 57 and 62A(,) respectively. These relatively large distances suggest that the C terminus is in an extended, relatively unstructured conformation. Nevertheless, we observed ligand-specific changes in FRET. All ligands induced an increase in FRET between the proximal C-terminal FlAsH site and Cys-265. Ligands that have been shown to induce arrestin-dependent ERK activation, including the catecholamine agonists and the inverse agonist ICI118551, led to a decrease in FRET between the distal FlAsH site and Cys-265, whereas other ligands had no effect or induced a small increase in FRET. Taken together the results provide new insight into the structure of the C terminus of the beta(2)-AR as well as ligand-induced conformational changes that may be relevant to arrestin-dependent regulation and signaling.
Collapse
Affiliation(s)
- Sébastien Granier
- Department of Molecular, Stanford University School of Medicine, Stanford, California 94305, USA
| | | | | | | | | | | | | |
Collapse
|
11
|
Eftink MR. Fluorescence techniques for studying protein structure. METHODS OF BIOCHEMICAL ANALYSIS 2006; 35:127-205. [PMID: 2002770 DOI: 10.1002/9780470110560.ch3] [Citation(s) in RCA: 230] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- M R Eftink
- Department of Chemistry, University of Mississippi
| |
Collapse
|
12
|
Photogeneration of quinone methide-type intermediates from pyridoxine and derivatives. J Photochem Photobiol A Chem 2002. [DOI: 10.1016/s1010-6030(01)00654-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
13
|
Ruan K, Li J, Liang R, Xu C, Yu Y, Lange R, Balny C. A rare protein fluorescence behavior where the emission is dominated by tyrosine: case of the 33-kDa protein from spinach photosystem II. Biochem Biophys Res Commun 2002; 293:593-7. [PMID: 12054643 DOI: 10.1016/s0006-291x(02)00247-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
An abnormal fluorescence emission of protein was observed in the 33-kDa protein which is one component of the three extrinsic proteins in spinach photosystem II particle (PS II). This protein contains one tryptophan and eight tyrosine residues, belonging to a "B type protein". It was found that the 33-kDa protein fluorescence is very different from most B type proteins containing both tryptophan and tyrosine residues. For most B type proteins studied so far, the fluorescence emission is dominated by the tryptophan emission, with the tyrosine emission hardly being detected when excited at 280 nm. However, for the present 33-kDa protein, both tyrosine and tryptophan fluorescence emissions were observed, the fluorescence emission being dominated by the tyrosine residue emission upon a 280 nm excitation. The maximum emission wavelength of the 33-kDa protein tryptophan fluorescence was at 317 nm, indicating that the single tryptophan residue is buried in a very strong hydrophobic region. Such a strong hydrophobic environment is rarely observed in proteins when using tryptophan fluorescence experiments. All parameters of the protein tryptophan fluorescence such as quantum yield, fluorescence decay, and absorption spectrum including the fourth derivative spectrum were explored both in the native and pressure-denatured forms.
Collapse
Affiliation(s)
- Kangcheng Ruan
- Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Science Chinese Academy of Sciences, 320, Yue-Yang Road, Shanghai 200031, China.
| | | | | | | | | | | | | |
Collapse
|
14
|
Pari K, Sundari CS, Chandani S, Balasubramanian D. beta-carbolines that accumulate in human tissues may serve a protective role against oxidative stress. J Biol Chem 2000; 275:2455-62. [PMID: 10644699 DOI: 10.1074/jbc.275.4.2455] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
beta-Carbolines are tricyclic nitrogen heterocycles formed in plants and animals as Maillard reaction products between amino acids and reducing sugars or aldehydes. They are being detected increasingly in human tissues, and their physiological roles need to be understood. Two beta-carboline carboxylates have been reported to accumulate in the human eye lens. We report here on the identification of another beta-carboline, namely 1-methyl-1-vinyl -2, 3,4-trihydro-beta-carboline-3-carboxylic acid, in the lenses of some cataract patients from India. Analysis of these three lenticular beta-carbolines using photodynamic and antioxidant assays shows all of them to be inert as sensitizers and effective as antioxidants; they quench singlet oxygen, superoxide and hydroxyl radicals and inhibit the oxidative formation of higher molecular weight aggregates of the test protein, eye lens gamma-crystallin. Such antioxidative ability of beta-carbolines is of particular relevance to the lens, which faces continual photic and oxidative stress. The beta-carboline diacid IV is also seen to display an unexpected ability of inhibiting the thermal coagulation of gamma-crystallin and the dithiothreitol-induced precipitation of insulin. These results offer experimental support to earlier suggestions that one of the roles that the beta-carbolines have is to offer protection against oxidative stress to the human tissues where they accumulate.
Collapse
Affiliation(s)
- K Pari
- Centre for Cellular and Molecular Biology, Hyderabad 500 007, L. V. Prasad Eye Institute, Hyderabad 500 034, India
| | | | | | | |
Collapse
|
15
|
Chattopadhyay A, Rukmini R, Mukherjee S. Photophysics of a neurotransmitter: ionization and spectroscopic properties of serotonin. Biophys J 1996; 71:1952-60. [PMID: 8889169 PMCID: PMC1233661 DOI: 10.1016/s0006-3495(96)79393-1] [Citation(s) in RCA: 78] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The neurotransmitter serotonin plays a modulatory role in the regulation of various cognitive and behavioral functions such as sleep, mood, pain, depression, anxiety, and learning by binding to a number of serotonin receptors present upon the cell surface. The spectroscopic properties of serotonin and their modulation with ionization state have been studied. Results show that serotonin fluorescence, as measured by its intensity, emission maximum, and lifetime, is pH dependent. These results are further supported by absorbance changes that show very similar pH dependence. Changes in fluorescence intensity and absorbance as a function of pH are consistent with a pK(a) of 10.4 +/- 0.2. The ligand-binding site for serotonin receptors is believed to be located in one of the transmembrane domains of the receptors. To develop a basis for monitoring the binding of serotonin to its receptors, its fluorescence in nonpolar media has been studied. No significant binding or partitioning of serotonin to membranes under physiological conditions was observed. Serotonin fluorescence in solvents of lower polarity is characterized by an enhancement in intensity and a blue shift in emission maximum, although the solvatochromism is much less pronounced than in tryptophan. In view of the multiple roles played by the serotonergic systems in the central and peripheral nervous systems, these results are relevant to future studies of serotonin and its binding to its receptors.
Collapse
Affiliation(s)
- A Chattopadhyay
- Centre for Cellular and Molecular Biology, Hyderabad, India.
| | | | | |
Collapse
|
16
|
Ben-Kasus T, Markel A, Torchinsky YM, Phillips RS, Parola AH. Interactions of Escherichia coli tryptophanase with quasisubstrates and monovalent cations studied by the circular dichroism and fluorescence methods. BIOCHIMICA ET BIOPHYSICA ACTA 1996; 1294:147-52. [PMID: 8645732 DOI: 10.1016/0167-4838(96)00004-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The reaction of tryptophanase and its W330F and W248F mutant forms with quasi-substrates forming an external pyridoxal phosphate aldimine or quinonoid is accompanied by the appearance of a positive circular dichroism (CD) peak at 290 nm. The peak seems to arise from a Tyr residue undergoing reorientation during the reaction. The peak does not appear upon formation of non-covalent Michaelis complexes of the enzyme with quasi-substrates such as indolepropionate, beta-phenyllactate and alpha-methylphenylalanine. The non-covalent complexes and external aldimines exhibit similar absorption spectra but can be distinguished by their CD and by the intensity of their fluorescence. Formation of the non-covalent complexes leads to an increase in positive CD at 420 nm while formation of the external aldimines leads to disappearance of the positive CD at 420 nm and its replacement by negative CD; it also leads to strong quenching of the coenzyme fluorescence at 500 nm. The quantum yield of fluorescence of the external aldimines is 6-times lower than that of the internal aldimine. Activating cations (K+, NH4+) strongly diminish the intensity of a negative protein CD band at 275 nm. From a comparison of the intensity of this band in the spectra of the wild-type holo- and apoenzyme and in the tryptophan mutants, it was deduced that the band belongs to a Tyr residue, which may be a part of the cation-binding site or located in its immediate vicinity.
Collapse
Affiliation(s)
- T Ben-Kasus
- Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | | | | | | | | |
Collapse
|
17
|
Reddy PS, Chatterji D. Evidence for a pyrimidine-nucleotide-specific initiation site (the i site) on Escherichia coli RNA polymerase. Proximity relationship with the inhibitor binding domain. EUROPEAN JOURNAL OF BIOCHEMISTRY 1994; 225:737-45. [PMID: 7957189 DOI: 10.1111/j.1432-1033.1994.00737.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Escherichia coli RNA polymerase has two sites, the i and i + 1, for the binding of the first two substrates. The i site is template- and Mg(2+)-independent and purine-nucleotide-specific, whereas the i + 1 site is template- and Mg(2+)-dependent and shows no nucleotide preference. The specificity of the i site for purine nucleotides is well in accord with the fact that most promoters initiate with a purine nucleotide. But there are a few promoters that initiate with a pyrimidine nucleotide. Dinucleotide synthesis at these promoters is completely inhibited by rifampicin. Earlier studies have failed to identify an i site for pyrimidine nucleotides. In this paper, using a fluorescent analog of UTP, namely uridine 5'-[gamma-(5-sulfonic acid)naphthylamidate]-triphosphate, abbreviated as UTP[AmNS], we are able to show its binding to RNA polymerase, with a Kd of 0.8 microM, in the absence of Mg2+ and template. This suggests the presence of an i pyrimidine nucleotide site. The fact that UTP-[AmNS] is capable of initiating RNA synthesis from the i site is further evidenced by the abortive transcription analyses at the lac promoter. Fluorescence titration studies performed in the presence and absence of purine initiator molecules indicate that this site is different from the i purine site. Scatchard analysis of the above data indicates the presence of a single binding site for UTP[AmNS] in the absence of Mg2+. Moreover UTP[AmNS] binds to the core enzyme with a Kd of 3.0 microM implying that, unlike the i purine nucleotide site, the sigma protein confers a tighter binding of UTP-[AmNS] to the low-Kd site. Forster's energy transfer measurements using UTP[AmNS] as the donor and rifampicin as the acceptor have been used for estimation of the distance of the i pyrimidine nucleotide site from the rifampicin site. From these measurements, we infer that there is no direct interference of rifampicin with the first phosphodiester bond between two pyrimidine nucleotides.
Collapse
Affiliation(s)
- P S Reddy
- Centre for Cellular and Molecular Biology, Hyderabad, India
| | | |
Collapse
|
18
|
Guo L, Heinzinger NK, Stevenson M, Schopfer LM, Salhany JM. Inhibition of gp120-CD4 interaction and human immunodeficiency virus type 1 infection in vitro by pyridoxal 5'-phosphate. Antimicrob Agents Chemother 1994; 38:2483-7. [PMID: 7530934 PMCID: PMC284769 DOI: 10.1128/aac.38.10.2483] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Pyridoxal 5'-phosphate and related compounds were tested for their ability to inhibit gp120-CD4 interaction and human immunodeficiency virus infection in vitro. The results show that pyridoxal 5'-phosphate is a unique CD4 antagonist whose antiviral potency derives from the presence of both lysine-reactive and anionic substituents.
Collapse
Affiliation(s)
- L Guo
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha 68198-5120
| | | | | | | | | |
Collapse
|
19
|
Johnson DA, Nuss JM. The histrionicotoxin-sensitive ethidium binding site is located outside of the transmembrane domain of the nicotinic acetylcholine receptor: a fluorescence study. Biochemistry 1994; 33:9070-7. [PMID: 8049208 DOI: 10.1021/bi00197a007] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A novel, relatively photostable, long-wavelength fluorescent membrane probe, N-(Texas Red sulfonyl)-5(and 6)-dodecanoylamine (C12-Texas Red), was synthesized and used as an electronic energy acceptor for Förster fluorescence resonance energy transfer (FRET) between ethidium bound to a histrionicotoxin-sensitive binding site on the Torpedo nicotinic acetylcholine receptor (AChR) and the lipid membrane surface. FRET from membrane-partitioned 5-(N-dodecanoylamino)fluorescein (C12-fluorescein) to the membrane-partitioned C12-Texas Red was also determined with a parallel set of cuvettes to (1) compare FRET results with a donor in a known position in the membrane and (2) assess the surface density of the membrane-partitioned C12-Texas Red. Stern-Volmer analysis of the FRET results showed that C12-Texas Red quenched membrane-partitioned C12-fluorescein fluorescence 2.9 times more effectively than it quenched the receptor-bound ethidium fluorescence even though the Förster critical distances for the two donor-acceptor pairs were very similar (49.9 and 54.3 A, respectively). Analysis of the ethidium to C12-Texas Red FRET as a function of acceptor surface density with the assumptions that the donor is attached along the major axis of symmetry of a cylindrical protein embedded perpendicularly into the membrane (On-Axis FRET model) suggested that the distance of closest approach between the receptor-bound ethidium and the membrane surface was approximately 52 A. Because the minimum distance between the surface of the lipid-membrane domain and the major symmetry axis of the AChR is approximately 28 A, the FRET results strongly suggest that the ethidium binding site is not located near the entrance of the luminal transmembrane domain is generally assumed.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- D A Johnson
- Division of Biomedical Sciences, University of California, Riverside 92521-0121
| | | |
Collapse
|
20
|
Kumar KP, Reddy PS, Chatterji D. Proximity relationship between the active site of Escherichia coli RNA polymerase and rifampicin binding domain: a resonance energy-transfer study. Biochemistry 1992; 31:7519-26. [PMID: 1510938 DOI: 10.1021/bi00148a012] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Escherichia coli RNA polymerase has two subsites, i and i + 1, for the binding of the first two substrates, and the first phosphodiester bond is formed between them during the initiation of transcription. Various studies have shown earlier that the inhibitor rifampicin has little effect, if any, on the formation of this phosphodiester bond. On an earlier occasion, we measured the distance of the i nucleotide from the rifampicin binding site on RNA polymerase using Forster's energy-transfer mechanism [Kumar & Chatterji (1990) Biochemistry 29,317]. In this paper, the 1-aminonaphthalene-5-sulfonic acid (AmNS) derivative of UTP in the presence of 10 mM MgCl2 was used as an energy donor, and its distance from rifampicin was estimated. The modified nucleotide (gamma-AmNS)-UTP binds to RNA polymerase with a Kd of 3 microM and has one binding site in the presence of Mg(II) ion. Fluorescence titration studies performed with or without an initiator indicated that (gamma-AmNS)-UTP exclusively binds to RNA polymerase at the (i + 1) site in the presence of Mg(II). Rifampicin was found to form a 1:1 complex with RNA polymerase bound to labeled UTP. Rifampicin and (gamma-AmNS)-UTP have a substantial spectral overlap with an energy-transfer efficiency close to 50%. Labeled UTP shows a decrease in its excited-state lifetime when bound to the enzyme; the transfer efficiency calculated from lifetime measurements was found to be lower than that estimated from steady-state spectral analysis. Time-resolved emission spectral analysis was carried out to differentiate between the free and bound UTP over the enzyme surface.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- K P Kumar
- Centre for Cellular and Molecular Biology, Hyderabad, India
| | | | | |
Collapse
|
21
|
Valenzuela C, Kerr J, Johnson D. Quinacrine binds to the lipid-protein interface of the Torpedo acetylcholine receptor: a fluorescence study. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)42433-7] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
|
22
|
Doi Y, Hashimoto T, Yamaguchi H, Vertut-Doï A. Modification of gelsolin with 4-fluoro-7-nitrobenz-2-oxa-1,3-diazole. EUROPEAN JOURNAL OF BIOCHEMISTRY 1991; 199:277-83. [PMID: 1649046 DOI: 10.1111/j.1432-1033.1991.tb16121.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Pig plasma gelsolin was modified with the fluorescent reagent 4-fluoro-7-nitrobenz-2-oxa-1,3-diazole (NBD-F) for lysyl residues. The relationship between the gelsolin activity and the degree of NBD labeling suggested that a single lysyl residue, which reacted five times slower than the other reactive lysyl residues, was essential for the activity. Taking advantage of the slow reactivity of the essential residue, active NBD-gelsolin was prepared. Limited cleavage of NBD-gelsolin by chymotrypsin indicated that the fluorescent reagents were randomly incorporated into all fragments observed. When NBD-gelsolin formed a gelsolin/actin (1:2) complex in the presence of micromolar Ca2+, the fluorescence spectra of NBD-gelsolin were red-shifted by 5 nm and the intensity decreased by 30%. However, on binding to phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2), the fluorescence spectra were blue-shifted by 5 nm with a concomitant increase in intensity by 20%. The addition of PtdIns(4,5)P2 to the NBD-gelsolin actin (1:2) complex restored the fluorescence spectra to that obtained in the presence of PtdIns(4,5)P2 alone. These results indicated that NBD-gelsolin, selectively labeled on lysyl residues not essential for activity, can be a useful probe to monitor the binding of PtdIns(4,5)P2 and actin.
Collapse
Affiliation(s)
- Y Doi
- Department of Food Science, Kyoto Women's University, Japan
| | | | | | | |
Collapse
|
23
|
Azevedeo JR, Johnson DA. Temperature-dependent lateral and transverse distribution of the epidermal growth factor receptor in A431 plasma membranes. J Membr Biol 1990; 118:215-24. [PMID: 2077131 DOI: 10.1007/bf01868605] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
To elucidate further the structure and molecular dynamics of the epidermal growth factor receptor, temperature-dependent aggregation and extracellular protrusion of the epidermal growth factor receptor in isolated plasma membranes from A431 cells were examined by fluorescence energy-transfer techniques. Epidermal growth factor was labeled at the amino terminus with either fluorescein isothiocyanate or tetramethylrhodamine isothiocyanate. A radionuclide receptor displacement assay demonstrated the bioactivity of these derivatives. Aggregation of the epidermal growth factor receptor was measured by determining the increase in fluorescence energy transfer between receptor-bound fluorescein and tetramethylrhodamine-labeled epidermal growth factor. Energy transfer between receptor-bound fluorescent derivatives was reversibly greater at 37 than 4 degrees C, indicating temperature-dependent aggregation of the receptor. The extracellular protrusion of the epidermal growth factor receptor was calculated from the magnitude of energy transfer between receptor-bound fluorescein labeled epidermal growth factor and 5-(N-dodecanoylamino)-eosin partitioned into the lipid membrane at 4 and 37 degrees C. No significant change in the distance of closest approach between the N-terminus of epidermal growth factor and the plasma membrane was observed at 4 degrees C (69 +/- 2 A) and 37 degrees C (67 +/- 2 A). Thus, the extracellular protrusion of the occupied epidermal growth factor receptor did not change detectably upon receptor aggregation.
Collapse
Affiliation(s)
- J R Azevedeo
- Division of Biomedical Sciences, University of California, Riverside 92521-0121
| | | |
Collapse
|
24
|
Tsai AL, Hsu MJ, Wu KK. Characterization of the interaction between prostacyclin and human serum albumin using a fluorescent analogue, 2,6-dichloro-4-aminophenol iloprost. BIOCHIMICA ET BIOPHYSICA ACTA 1989; 993:74-82. [PMID: 2478194 DOI: 10.1016/0304-4165(89)90145-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
We synthesized a fluorescent probe, 2,6-dichloro-4-aminophenol iloprost or dichlorohydroxyphenylamide of iloprost (DCHPA-iloprost) by reacting the stable prostacyclin analog, iloprost (ZK 35 374), with 2,6-dichloro-4-aminophenol with a yield of 60%. This probe exhibited an optical spectrum which overlapped with the emission spectrum of the sole tryptophan of human serum albumin (HSA). Energy transfer from the tryptophan residue to the phenol moiety of DCHPA-iloprost was observed. We utilized this donor-quenching phenomenon to quantitate the binding stoichiometry and affinity as well as the association rate of DCHPA-iloprost binding to HSA. As DCHPA-iloprost showed similar binding characteristics similar to those of iloprost and prostacyclin and competed with iloprost for HSA binding sites, we used DCHPA-iloprost as a probe to locate the binding domain of prostacyclin (PGI2) in HSA. The distance between the tryptophan indole and the phenol group of DCHPA-iloprost was estimated to be 15-18 A. Because iloprost binding to HSA was competitive with warfarin and not with free fatty acid, we propose that PGI2 binds to the 'domain 2' of HSA was competitive with warfarin and not with free fatty acid, we propose that PGI2 binds to the 'domain 2' of HSA molecules. A possible molecular mechanism by which HSA reduces the chemical degradation of PGI2 and stabilizes its activity could be derived from this model.
Collapse
Affiliation(s)
- A L Tsai
- Department of Internal Medicine, University of Texas Health Science Center, Houston 77225
| | | | | |
Collapse
|
25
|
First EA, Taylor SS. Selective modification of the catalytic subunit of cAMP-dependent protein kinase with sulfhydryl-specific fluorescent probes. Biochemistry 1989; 28:3598-605. [PMID: 2742857 DOI: 10.1021/bi00434a067] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The catalytic subunit of cAMP-dependent protein kinase contains only two cysteine residues, and the side chains of both Cys 199 and Cys 343 are accessible. Modification of the catalytic subunit by a variety of sulfhydryl-specific reagents leads to the loss of enzymatic activity. The differential reactivity of the two sulfhydryl groups at pH 6.5 has been utilized to selectively modify each cysteine with the following fluorescent probes: 3,6,7-trimethyl-4-(bromomethyl)-1,5-diazabicyclo[3.3.0]octa-3,6-diene- 2,8-dione, N-(iodoacetyl)-N'-(5-sulfo-1-naphthyl)ethylenediamine, and 4-[N-[(iodoacetoxy)ethyl]-N-methyl-amino]-7-nitrobenz-2-oxa-1,3-diazole. The most reactive cysteine is Cys 199, and exclusive modification of this residue was achieved with each reagent at pH 6.5. Modification of Cys 343 required reversible blocking of Cys 199 with 5,5'-dithiobis(2-nitrobenzoic acid) followed by reaction of Cys 343 with the fluorescent probe at pH 8.3. Treatment of this modified catalytic subunit with reducing reagent restored catalytic activity by unblocking Cys 199. In contrast, catalytic subunit that was selectively labeled at Cys 199 by the fluorescent probes was catalytically inactive. Even though Cys 199 is presumably close to the interaction site between the regulatory subunit and the catalytic subunit, all of the modified C-subunits retained the capacity to aggregate with the type II regulatory subunit in the absence of cAMP, and the resulting holoenzymes were dissociated in the presence of cAMP.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- E A First
- Department of Chemistry, University of California, San Diego, La Jolla 92093
| | | |
Collapse
|
26
|
|
27
|
Fluorescence resonance energy transfer studies on the proximity relationship between the intrinsic metal ion and substrate binding sites of Escherichia coli RNA polymerase. J Biol Chem 1987. [DOI: 10.1016/s0021-9258(18)45180-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
|
28
|
Herman BA, Fernandez SM. Fluorescent pyrene derivative of concanavalin A: preparation and spectroscopic characterization. Biochemistry 1982; 21:3271-5. [PMID: 7115668 DOI: 10.1021/bi00257a004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
|
29
|
Herman BA, Fernandez SM. A fluorescent coumarin derivative of alpha-bungarotoxin. Synthesis and spectroscopic characterization. Biochem Biophys Res Commun 1981; 103:1112-9. [PMID: 7332577 DOI: 10.1016/0006-291x(81)90923-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
|
30
|
Mikes V, Kovár J. Interaction of liposomes with homologous series of fluorescent berberine derivatives. New cationic probes for measuring membrane potential. BIOCHIMICA ET BIOPHYSICA ACTA 1981; 640:341-51. [PMID: 7213690 DOI: 10.1016/0005-2736(81)90557-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The interaction of liposomes with a series of fluorescent berberine derivatives having different alkyl chain lengths has been investigated. The hydrophobicity of the binding site on the phospholipid membrane increases and mobility decreases with the length of the alkyl chain. If lauryl sulphate micelles are used to bind berberines, the hydrophobicity of the binding site is the same for all derivatives. The dye series represents a model with constant charge and growing lipophilicity. Both electrostatic forces and lipophilicity play an important role in binding. By virtue of the excellent sensitivity of the dyes to medium polarity, berberines prove to be suitable probes for measuring membrane potential, but only in cases when a negative charge is generated in the liposomal interior. The fluorescent response is a linear function of the potential magnitude.
Collapse
|
31
|
Bergqvist Y, Frisk-Holmberg M. Sensitive method for the determination of chloroquine and its metabolite desethyl-chloroquine in human plasma and urine by high-performance liquid chromatography. JOURNAL OF CHROMATOGRAPHY 1980; 221:119-27. [PMID: 7451613 DOI: 10.1016/s0378-4347(00)81013-0] [Citation(s) in RCA: 82] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
A method has been developed for the rapid quantitative analysis of chloroquine and its metabolite desethyl-chloroquine in plasma, blood and urine using high-performance liquid chromatography. An ethylene dichloride extract of the alkalinized biological samples was extracted with dilute acid and chromatographed on a reversed-phase column. Phosphate buffer in acetonitrile was used as the mobile phase with perchlorate as the counter-ion. Ultraviolet absorption at 254 or 340 nm or fluorescence detection was used. The fluorescence spectra and the fluorescence quantum yield of the substances were determined. Chloroquine and desethyl-chloroquine concentrations in the range of 10 nmol/l (UV-detection) and of 0.5 nmol/l (fluorescence detection) could be accurately measured with a relative standard deviation of 12%. The method should be adequate for therapeutic and pharmacokinetic studies.
Collapse
|
32
|
Brand JG, Cagan RH. Fluorescence characteristics of native and denatured monellin. BIOCHIMICA ET BIOPHYSICA ACTA 1977; 493:178-87. [PMID: 880312 DOI: 10.1016/0005-2795(77)90270-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
|
33
|
Weiner RE, Ettinger MJ, Kosman DJ. Fluorescence properties of the copper enzyme galactose oxidase and its tryptophan-modified derivatives. Biochemistry 1977; 16:1602-6. [PMID: 557987 DOI: 10.1021/bi00627a012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Galactose oxidase contains a single nonblue Cu(II) atom and 18 tryptophan residues per molecule. Removal of the copper atom reveals that it has an approximately 29% quenching effect on the relative quantum yield of fluorescence. While saturating concentrations of the sugar substrate of galactose oxidase also reduce the quantum yield, the second substrate, oxygen, has no significant effect on fluorescence in the absence of the sugar substrate. N-Bromosuccinimide (NBS) inactivates galactose oxidase as two tryptophans are oxidized (Kosman, D. J., Ettinger, M. J., Bereman, R. D., and Giordano, R. S. (1977), Biochemistry, 16). Oxidation of two tryptophans also leads to a disproportionately large decrease in fluorescence intensity. A 23% reduction in quantum yield with blue-shift occurs with oxidation of 0.85 tryptophan equiv and a further 25% quenching is obtained as the reaction proceeds to 2.0 residues oxidized. Fluorescence experiments with the modified enzyme show that it contains at least one tryptophan residue which is unreactive towards NBS, but which also interacts with the Cu(II) atom and substrate. These results taken together substantiate the postulate that one or more tryptophan residues, the Cu(II) atom, and the sugar substrate mutually interact within the native enzyme. Energy-transfer calculations suggest that this residue(s) which must be within a relatively hydrophobic environment is at least 12 A from the Cu(II) atom.
Collapse
|
34
|
Dolara P, Franconi F, Manghi N. The effect of phalloidin on natural and U.V. denatured bovine serum albumin. PHARMACOLOGICAL RESEARCH COMMUNICATIONS 1977; 9:339-47. [PMID: 559309 DOI: 10.1016/s0031-6989(77)80040-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
|
35
|
Pearce KN. A fluorescence study of the temperature-dependent polymerization of bovine beta-casein A1. EUROPEAN JOURNAL OF BIOCHEMISTRY 1975; 58:23-9. [PMID: 241633 DOI: 10.1111/j.1432-1033.1975.tb02344.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The intrinsic fluorescence properties of bovine beta-casein A1 solutions have been studied under a variety of conditions. The protein shows both tyrosine and tryptophan fluorescence emission, the former being more pronounced at low temperature (5 degrees C) and in the presence of urea. Approximate relative quantum yields for the tyrosine and tryptophan residues were determined using free tyrosine and free tryptophan respectively as standards. The tryptophan emission intensity of beta-casein shows an increase with temperature indicating a temperature-dependent transition of the protein. Two-state analysis of the emission-intensity--temperature data yielded positive enthalpy and entropy values for the transition over a range of protein concentrations (0.018--0.18%). A marked protein concentration effect was apparent which indicated that the transition was a consequence of polymerization rather than a prerequisite for polymerization. The size of the polymers appeared to be concentration-dependent. Decreased ionic strength and increased pH both caused a reduction in the increase in emission intensity when the temperature was increased. At higher pH both the enthalpy and the entropy for the transition were reduced. Experimental precision was insufficient to allow the effect of decreased ionic strength on these parameters to be determined. Many of the properties of the temperature-dependent transition can be explained if the transition is considered to be one of micelle formation.
Collapse
|
36
|
Kempe TD, Stark GR. Pyridoxal 5'-phosphate, a fluorescent probe in the active site of aspartate transcarbamylase. J Biol Chem 1975. [DOI: 10.1016/s0021-9258(19)41011-9] [Citation(s) in RCA: 40] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
|
37
|
Keeler JD, Sharma RP. Interaction of promazine with bovine serum albumin and hexadecyltrimethylammonium bromide using light absorption and fluorometric techniques. Biochem Pharmacol 1974; 23:2679-87. [PMID: 4473035 DOI: 10.1016/0006-2952(74)90038-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|
38
|
|
39
|
|
40
|
Udenfriend S, Stein S, Böhlen P, Dairman W, Leimgruber W, Weigele M. Fluorescamine: a reagent for assay of amino acids, peptides, proteins, and primary amines in the picomole range. Science 1972; 178:871-2. [PMID: 5085985 DOI: 10.1126/science.178.4063.871] [Citation(s) in RCA: 1973] [Impact Index Per Article: 37.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Fluorescamine is a new reagent for the detection of primary amines in the picomole range. Its reaction with amines is almost instantaneous at room temperature in aqueous media. The products are highly fluorescent, whereas the reagent and its degradation products are nonfluorescent. Applications are discussed.
Collapse
|
41
|
Cortijo M, Shaltiel S. On the microenvironment of the pyridoxamine 5-phosphate residue in NaBH 4 -reduced glycogen phosphorylase b. Absorption and fluorescence studies. EUROPEAN JOURNAL OF BIOCHEMISTRY 1972; 29:134-42. [PMID: 4673365 DOI: 10.1111/j.1432-1033.1972.tb01967.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
|
42
|
Honikel KO, Madsen NB. Comparison of the Absorbance Spectra and Fluorescence Behavior of Phosphorylase b with that of Model Pyridoxal Phosphate Derivatives in Various Solvents. J Biol Chem 1972. [DOI: 10.1016/s0021-9258(19)45615-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
|
43
|
Forrey AW, Olsgaard RB, Nolan C, Fischer EH. Synthesis and properties of alpha and epsilon pyridoxyl lysines and their phosphorylated derivatives. Biochimie 1971; 53:269-81. [PMID: 5564218 DOI: 10.1016/s0300-9084(71)80093-7] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
|
44
|
|
45
|
Cortijo M, Shaltiel S. A built-in fluorescent probe in NaBH4-reduced glycogen phosphorylase. Biochem Biophys Res Commun 1970; 39:212-6. [PMID: 5439510 DOI: 10.1016/0006-291x(70)90780-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
|
46
|
Chen RF. Fluorescent protein-dye conjugates. II. Gamma globulin conjugated with various dyes. Arch Biochem Biophys 1969; 133:263-76. [PMID: 4186001 DOI: 10.1016/0003-9861(69)90454-8] [Citation(s) in RCA: 79] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
|
47
|
Chen RF. Fluorescent protein--dye conjugates. I. Heterogeneity of sites on serum albumin labeled by dansyl chloride. Arch Biochem Biophys 1968; 128:163-75. [PMID: 5677176 DOI: 10.1016/0003-9861(68)90019-2] [Citation(s) in RCA: 43] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
|
48
|
Goldberg ME, York S, Stryer L. Fluorescence studies of substrate and subunit interactions of the beta-2 protein of Escherichia coli tryptophan synthetase. Biochemistry 1968; 7:3662-7. [PMID: 4878703 DOI: 10.1021/bi00850a045] [Citation(s) in RCA: 85] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
|
49
|
Miles EW, Hatanaka M, Crawford IP. A new thiol-dependent transamination reaction catalyzed by the B protein of Escherichia coli tryptophan synthetase. Biochemistry 1968; 7:2742-53. [PMID: 4877071 DOI: 10.1021/bi00848a008] [Citation(s) in RCA: 65] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
|
50
|
Chen RF. Fluorescence of protonated excited-state forms of 5-hydroxytryptamine (serotonin) and related indoles. Proc Natl Acad Sci U S A 1968; 60:598-605. [PMID: 5303878 PMCID: PMC225089 DOI: 10.1073/pnas.60.2.598] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
|