1
|
Bianco PR. Insight into the biochemical mechanism of DNA helicases provided by bulk-phase and single-molecule assays. Methods 2021; 204:348-360. [PMID: 34896247 PMCID: PMC9534331 DOI: 10.1016/j.ymeth.2021.12.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 12/01/2021] [Accepted: 12/03/2021] [Indexed: 10/19/2022] Open
Abstract
There are multiple assays available that can provide insight into the biochemical mechanism of DNA helicases. For the first 22 years since their discovery, bulk-phase assays were used. These include gel-based, spectrophotometric, and spectrofluorometric assays that revealed many facets of these enzymes. From 2001, single-molecule studies have contributed additional insight into these DNA nanomachines to reveal details on energy coupling, step size, processivity as well as unique aspects of individual enzyme behavior that were masked in the averaging inherent in ensemble studies. In this review, important aspects of the study of helicases are discussed including beginning with active, nuclease-free enzyme, followed by several bulk-phase approaches that have been developed and still find widespread use today. Finally, two single-molecule approaches are discussed, and the resulting findings are related to the results obtained in bulk-phase studies.
Collapse
Affiliation(s)
- Piero R Bianco
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE 68198-6025, USA.
| |
Collapse
|
2
|
López-Alled CM, Park SJ, Lee DJ, Murfin LC, Kociok-Köhn G, Hann JL, Wenk J, James TD, Kim HM, Lewis SE. Azulene-based fluorescent chemosensor for adenosine diphosphate. Chem Commun (Camb) 2021; 57:10608-10611. [PMID: 34570136 DOI: 10.1039/d1cc04122c] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
AzuFluor® 435-DPA-Zn, an azulene fluorophore bearing two zinc(II)-dipicolylamine receptor motifs, exhibits fluorescence enhancement in the presence of adenosine diphosphate. Selectivity for ADP over ATP, AMP and PPi results from appropriate positioning of the receptor motifs, since an isomeric sensor cannot discriminate between ADP and ATP.
Collapse
Affiliation(s)
- Carlos M López-Alled
- Department of Chemistry, University of Bath, Bath, BA2 7AY, UK. .,Centre for Sustainable Circular Technologies, University of Bath, Bath, BA2 7AY, UK.
| | - Sang Jun Park
- Department of Energy Systems Research, Ajou University, Suwon 443-749, South Korea.
| | - Dong Joon Lee
- Department of Energy Systems Research, Ajou University, Suwon 443-749, South Korea.
| | - Lloyd C Murfin
- Department of Chemistry, University of Bath, Bath, BA2 7AY, UK.
| | - Gabriele Kociok-Köhn
- Material and Chemical Characterisation Facility (MC2), University of Bath, Bath, BA2 7AY, UK
| | - Jodie L Hann
- Department of Chemistry, University of Bath, Bath, BA2 7AY, UK.
| | - Jannis Wenk
- Centre for Sustainable Circular Technologies, University of Bath, Bath, BA2 7AY, UK. .,Department of Chemical Engineering, University of Bath, Bath, BA2 7AY, UK
| | - Tony D James
- Department of Chemistry, University of Bath, Bath, BA2 7AY, UK. .,Centre for Sustainable Circular Technologies, University of Bath, Bath, BA2 7AY, UK. .,School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang 453007, China
| | - Hwan Myung Kim
- Department of Energy Systems Research, Ajou University, Suwon 443-749, South Korea.
| | - Simon E Lewis
- Department of Chemistry, University of Bath, Bath, BA2 7AY, UK. .,Centre for Sustainable Circular Technologies, University of Bath, Bath, BA2 7AY, UK.
| |
Collapse
|
3
|
Measurement of Nucleotide Hydrolysis Using Fluorescent Biosensors for Phosphate. Methods Mol Biol 2021; 2263:289-318. [PMID: 33877604 DOI: 10.1007/978-1-0716-1197-5_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Assays for the detection of inorganic phosphate (Pi) are widely used to measure the activity of nucleotide hydrolyzing enzymes, such as ATPases and GTPases. The fluorescent biosensors for Pi, described here, are based on fluorescently labeled versions of E. coli phosphate-binding protein (PBP), which translates Pi binding into a large change in fluorescence intensity. In comparison with other Pi-detection systems, these biosensors are characterized by a high sensitivity (sub-micromolar Pi concentrations) and high time resolution (tens of milliseconds), and they are therefore particularly well suited for measurements of phosphate ester hydrolysis in real time. In this chapter, it is described how the Pi biosensors can be used to measure kinetics of ATPase and GTPase reactions, both under steady state and pre-steady state conditions. An example protocol is given for determining steady state kinetic parameters, Km and kcat, of the ATP-dependent chromatin remodeler Chd1, in a plate reader format. In addition, the measurement of Pi release kinetics under pre-steady state conditions is described, including a detailed experimental procedure for a single turnover measurement of ATP hydrolysis by the ABC-type ATPase SufBC using rapid mixing.
Collapse
|
4
|
Karatas H, Akbarzadeh M, Adihou H, Hahne G, Pobbati AV, Yihui Ng E, Guéret SM, Sievers S, Pahl A, Metz M, Zinken S, Dötsch L, Nowak C, Thavam S, Friese A, Kang C, Hong W, Waldmann H. Discovery of Covalent Inhibitors Targeting the Transcriptional Enhanced Associate Domain Central Pocket. J Med Chem 2020; 63:11972-11989. [PMID: 32907324 PMCID: PMC7586386 DOI: 10.1021/acs.jmedchem.0c01275] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
![]()
Transcriptional enhanced associate
domain (TEAD) transcription
factors together with coactivators and corepressors modulate the expression
of genes that regulate fundamental processes, such as organogenesis
and cell growth, and elevated TEAD activity is associated with tumorigenesis.
Hence, novel modulators of TEAD and methods for their identification
are in high demand. We describe the development of a new “thiol
conjugation assay” for identification of novel small molecules
that bind to the TEAD central pocket. The assay monitors prevention
of covalent binding of a fluorescence turn-on probe to a cysteine
in the central pocket by small molecules. Screening of a collection
of compounds revealed kojic acid analogues as TEAD inhibitors, which
covalently target the cysteine in the central pocket, block the interaction
with coactivator yes-associated protein with nanomolar apparent IC50 values, and reduce TEAD target gene expression. This methodology
promises to enable new medicinal chemistry programs aimed at the modulation
of TEAD activity.
Collapse
Affiliation(s)
- Hacer Karatas
- Department of Chemical Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn Straße 11, 44227 Dortmund, Germany
| | - Mohammad Akbarzadeh
- Department of Chemical Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn Straße 11, 44227 Dortmund, Germany
| | - Hélène Adihou
- Department of Chemical Biology, AstraZeneca-Max Planck Institute Satellite Unit, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany.,Medicinal Chemistry, Research and Early Development Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, SE-431 83 Gothenburg, Sweden
| | - Gernot Hahne
- Department of Chemical Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn Straße 11, 44227 Dortmund, Germany
| | - Ajaybabu V Pobbati
- Institute of Molecular and Cell Biology, A*STAR, 61 Biopolis Drive, 138673 Singapore, Singapore
| | - Elizabeth Yihui Ng
- Experimental Drug Development Centre (EDDC), Agency for Science, Technology and Research (A*STAR), 10 Biopolis Road, Chromos, #05-01, 138670, Singapore
| | - Stéphanie M Guéret
- Department of Chemical Biology, AstraZeneca-Max Planck Institute Satellite Unit, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany.,Medicinal Chemistry, Research and Early Development Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, SE-431 83 Gothenburg, Sweden
| | - Sonja Sievers
- Department of Chemical Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn Straße 11, 44227 Dortmund, Germany
| | - Axel Pahl
- Department of Chemical Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn Straße 11, 44227 Dortmund, Germany
| | - Malte Metz
- Department of Chemical Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn Straße 11, 44227 Dortmund, Germany
| | - Sarah Zinken
- Department of Chemical Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn Straße 11, 44227 Dortmund, Germany.,Faculty of Chemistry and Chemical Biology, Technical University Dortmund, Otto-Hahn-Straße 6, 44227 Dortmund, Germany
| | - Lara Dötsch
- Department of Chemical Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn Straße 11, 44227 Dortmund, Germany.,Faculty of Chemistry and Chemical Biology, Technical University Dortmund, Otto-Hahn-Straße 6, 44227 Dortmund, Germany
| | - Christine Nowak
- Department of Chemical Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn Straße 11, 44227 Dortmund, Germany
| | - Sasikala Thavam
- Department of Chemical Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn Straße 11, 44227 Dortmund, Germany
| | - Alexandra Friese
- Department of Chemical Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn Straße 11, 44227 Dortmund, Germany
| | - CongBao Kang
- Experimental Drug Development Centre (EDDC), Agency for Science, Technology and Research (A*STAR), 10 Biopolis Road, Chromos, #05-01, 138670, Singapore
| | - Wanjin Hong
- Institute of Molecular and Cell Biology, A*STAR, 61 Biopolis Drive, 138673 Singapore, Singapore
| | - Herbert Waldmann
- Department of Chemical Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn Straße 11, 44227 Dortmund, Germany.,Faculty of Chemistry and Chemical Biology, Technical University Dortmund, Otto-Hahn-Straße 6, 44227 Dortmund, Germany
| |
Collapse
|
5
|
Berni E, Le Henaff L, Jarrige L, Girard E, Jonusauskas G, Gosse I, Pinet S. Functionalized Ruthenium Complexes: Selective “Turn-on” Detection of Biologically Relevant Anionic Species. European J Org Chem 2017. [DOI: 10.1002/ejoc.201700586] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Emanuela Berni
- ISM; UMR 5255 CNRS; Univ. Bordeaux; 351 Cours de la libération 33400 Talence France
- ENSCBP; Bordeaux INP; 16 Avenue Pey Berland 33607 Pessac France
| | - Laurent Le Henaff
- ISM; UMR 5255 CNRS; Univ. Bordeaux; 351 Cours de la libération 33400 Talence France
- ENSCBP; Bordeaux INP; 16 Avenue Pey Berland 33607 Pessac France
| | - Lucie Jarrige
- ISM; UMR 5255 CNRS; Univ. Bordeaux; 351 Cours de la libération 33400 Talence France
- ENSCBP; Bordeaux INP; 16 Avenue Pey Berland 33607 Pessac France
| | - Emeline Girard
- ISM; UMR 5255 CNRS; Univ. Bordeaux; 351 Cours de la libération 33400 Talence France
- ENSCBP; Bordeaux INP; 16 Avenue Pey Berland 33607 Pessac France
| | - Gediminas Jonusauskas
- LOMA; UMR 5798; CNRS; Univ. Bordeaux; 351 Cours de la libération 33400 Talence France
| | - Isabelle Gosse
- ISM; UMR 5255 CNRS; Univ. Bordeaux; 351 Cours de la libération 33400 Talence France
- ENSCBP; Bordeaux INP; 16 Avenue Pey Berland 33607 Pessac France
| | - Sandra Pinet
- ISM; UMR 5255 CNRS; Univ. Bordeaux; 351 Cours de la libération 33400 Talence France
- ENSCBP; Bordeaux INP; 16 Avenue Pey Berland 33607 Pessac France
| |
Collapse
|
6
|
A novel photoelectrochemical immunosensor by integration of nanobody and ZnO nanorods for sensitive detection of nucleoside diphosphatase kinase-A. Anal Chim Acta 2017; 973:82-90. [PMID: 28502431 DOI: 10.1016/j.aca.2017.03.048] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 02/24/2017] [Accepted: 03/24/2017] [Indexed: 12/22/2022]
Abstract
Nucleoside diphosphatase kinase A (NDPK-A) is a metastasis-suppressor protein and a biomarker that act on a wide range cancer cells to inhibit the potential metastasis. Herein, we present a simple photoelectrochemical immunosensor based on ZnO nanorod arrays for the sensitive detection of NDPK-A. The ZnO nanorod arrays cosensitized with CdS nanoparticles and Mn2+ displayed a high and stable photocurrent response under irradiation. After anti-NPDK-A nanobodies were immobilized to the ZnO nanorod arrays, the proposed immunosensor can be utilized for detecting NPDK-A by monitoring the changes in the photocurrent signals of the electrode resulting from immunoreaction. Accordingly, the well-designed immunosensor exhibited a low limit of detection (LOD) of 0.3 pg mL-1 and a wide linear range from 0.5 pg mL-1 to 10 μg mL-1. The R2 of the regression curve is 0.99782. Meanwhile, the good stability, reproducibility and specificity of the resulting photoelectrochemical biosensor are demonstrated. In addition, the presented work would offer a novel and simple approach for the detection of immunoreactions and provide new insights in popularizing the diagnosis of NPDK-A.
Collapse
|
7
|
Huang F, Hao G, Wu F, Feng G. Fluorescence sensing of ADP over ATP and PPi in 100% aqueous solution. Analyst 2016. [PMID: 26213259 DOI: 10.1039/c5an01291k] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
An anthracene-bridged dinuclear zinc(ii)-dipicolylamine complex was found to show high selectivity for ADP with a significant fluorescence enhancement over ATP, PPi and other common analytes in 100% aqueous solution. This complex can be used for fluorescence detection of ADP in living cells and for monitoring the activity of kinases.
Collapse
Affiliation(s)
- Feihu Huang
- Key laboratory of Pesticide and Chemical Biology of Ministry of Education, College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan 430079, P. R. China.
| | | | | | | |
Collapse
|
8
|
Shi L, Hu P, Ren Y, Feng G. An unexpected highly selective mononuclear zinc complex for adenosine diphosphate (ADP). Chem Commun (Camb) 2014; 49:11704-6. [PMID: 24192643 DOI: 10.1039/c3cc47437b] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
A simple and readily available mononuclear zinc complex, which appends two anthracene groups, was unexpectedly found to show high selectivity for ADP with a unique increased fluorescence response in neutral aqueous solution.
Collapse
Affiliation(s)
- Lei Shi
- Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan 430079, P. R. China.
| | | | | | | |
Collapse
|
9
|
Coupling of two non-processive myosin 5c dimers enables processive stepping along actin filaments. Sci Rep 2014; 4:4907. [PMID: 24809456 PMCID: PMC4014986 DOI: 10.1038/srep04907] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 04/11/2014] [Indexed: 11/09/2022] Open
Abstract
Myosin 5c (Myo5c) is a low duty ratio, non-processive motor unable to move continuously along actin filaments though it is believed to participate in secretory vesicle trafficking in vertebrate cells. Here, we measured the ATPase kinetics of Myo5c dimers and tested the possibility that the coupling of two Myo5c molecules enables processive movement. Steady-state ATPase activity and ADP dissociation kinetics demonstrated that a dimer of Myo5c-HMM (double-headed heavy meromyosin 5c) has a 6-fold lower Km for actin filaments than Myo5c-S1 (single-headed myosin 5c subfragment-1), indicating that the two heads of Myo5c-HMM increase F-actin-binding affinity. Nanometer-precision tracking analyses showed that two Myo5c-HMM dimers linked with each other via a DNA scaffold and moved processively along actin filaments. Moreover, the distance between the Myo5c molecules on the DNA scaffold is an important factor for the processive movement. Individual Myo5c molecules in two-dimer complexes move stochastically in 30-36 nm steps. These results demonstrate that two dimers of Myo5c molecules on a DNA scaffold increased the probability of rebinding to F-actin and enabled processive steps along actin filaments, which could be used for collective cargo transport in cells.
Collapse
|
10
|
Fluorescent biosensors: design and application to motor proteins. EXPERIENTIA SUPPLEMENTUM (2012) 2014; 105:25-47. [PMID: 25095989 DOI: 10.1007/978-3-0348-0856-9_2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Reagentless biosensors are single molecular species that report the concentration of a specific target analyte, while having minimal impact on the system being studied. This chapter reviews such biosensors with emphasis on the ones that use fluorescence as readout and can be used for real-time assays of concentration changes with reasonably high time resolution and sensitivity. Reagentless biosensors can be designed with different types of recognition elements, particularly specific binding proteins and nucleic acids, including aptamers. Different ways are described in which a fluorescence signal can be used to report the target concentration. These include the use of single, environmentally sensitive fluorophores; FRET pairs, often used in genetically encoded biosensors; and pairs of identical fluorophores that undergo reversible stacking interactions to change fluorescence intensity. The applications of these biosensors in different types of real-time assays with motor proteins are described together with some specific examples. These encompass regulation and mechanism of motor proteins, using both steady-state assays and single-turnover measurements.
Collapse
|
11
|
Jeong HJ, Ohmuro-Matsuyama Y, Ohashi H, Ohsawa F, Tatsu Y, Inagaki M, Ueda H. Detection of vimentin serine phosphorylation by multicolor Quenchbodies. Biosens Bioelectron 2013; 40:17-23. [DOI: 10.1016/j.bios.2012.06.030] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Revised: 06/07/2012] [Accepted: 06/17/2012] [Indexed: 10/28/2022]
|
12
|
Abstract
The development of novel fluorescence methods for the detection of key biomolecules is of great interest, both in basic research and in drug discovery. Particularly relevant and widespread molecules in cells are ADP and GDP, which are the products of a large number of cellular reactions, including reactions catalysed by nucleoside triphosphatases and kinases. Previously, biosensors for ADP were developed in this laboratory, based on fluorophore adducts with the bacterial actin homologue ParM. It is shown in the present study that one of these biosensors, tetramethylrhodamine–ParM, can also monitor GDP. The biosensor can be used to measure micromolar concentrations of GDP on the background of millimolar concentrations of GTP. The fluorescence response of the biosensor is fast, the response time being <0.2 s. Thus the biosensor allows real-time measurements of GTPase and GTP-dependent kinase reactions. Applications of the GDP biosensor are exemplified with two different GTPases, measuring the rates of GTP hydrolysis and nucleotide exchange.
Collapse
|
13
|
Toseland CP, Webb MR. Fluorescence tools to measure helicase activity in real time. Methods 2010; 51:259-68. [DOI: 10.1016/j.ymeth.2010.02.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2009] [Revised: 02/03/2010] [Accepted: 02/12/2010] [Indexed: 11/16/2022] Open
|
14
|
Abstract
ATP-driven translocation of helicases along DNA can be assayed in several ways. Reagentless biosensors, based on fluorophore-protein adducts, provide convenient ways for real-time assays of both the separation of dsDNA and the hydrolysis of ATP. Single-stranded DNA can be assayed using a modified single-stranded DNA-binding protein (SSB), and phosphate production during ATP hydrolysis can be measured by a modified phosphate-binding protein. Advantages and limitations of these approaches are compared with those of other types of measurements.
Collapse
Affiliation(s)
- Martin R Webb
- MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London, UK
| |
Collapse
|
15
|
Hackney DD. When is weaker better? Design of an ADP sensor with weak ADP affinity, but still selective against ATP. ACS Chem Biol 2010; 5:353-4. [PMID: 20394442 DOI: 10.1021/cb1000839] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A simple ADP biosensor would be of broad usefulness in monitoring the large number of metabolic processes that produce ADP. Several new systems have been recently described including one in the current issue of ACS Chemical Biology that provides a simple readout of the ADP concentration without significant interference by ATP.
Collapse
Affiliation(s)
- David D. Hackney
- Department of Biological Sciences, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213
| |
Collapse
|
16
|
Kunzelmann S, Webb MR. A biosensor for fluorescent determination of ADP with high time resolution. J Biol Chem 2009; 284:33130-8. [PMID: 19801632 PMCID: PMC2785155 DOI: 10.1074/jbc.m109.047118] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Nearly every cellular process requires the presence of ATP. This is reflected in the vast number of enzymes like kinases or ATP hydrolases, both of which cleave the terminal phosphate from ATP, thereby releasing ADP. Despite the fact that ATP hydrolysis is one of the most fundamental reactions in biological systems, there are only a few methods available for direct measurements of enzymatic-driven ATP conversion. Here we describe the development of a reagentless biosensor for ADP, the common product of all ATPases and kinases, which allows the real-time detection of ADP, produced enzymatically. The biosensor is derived from a bacterial actin homologue, ParM, as protein framework. A single fluorophore (a diethylaminocoumarin), attached to ParM at the edge of the nucleotide binding site, couples ADP binding to a >3.5-fold increase in fluorescence intensity. The labeled ParM variant has high affinity for ADP (0.46 μm) and a fast signal response, controlled by the rate of ADP binding to the sensor (0.65 μm−1s−1). Amino acids in the active site were mutated to reduce ATP affinity and achieve a >400-fold discrimination against triphosphate binding. A further mutation ensured that the final sensor did not form filaments and, as a consequence, has extremely low ATPase activity. The broad applicability of N-[2-(1-maleimidyl)ethyl]-7-diethylaminocoumarin-3-carboxamide (MDCC)-ParM as a sensitive probe for ADP is demonstrated in real-time kinetic assays on two different ATPases and a protein kinase.
Collapse
Affiliation(s)
- Simone Kunzelmann
- MRC National Institute for Medical Research, Mill Hill, London NW7 1AA, United Kingdom
| | | |
Collapse
|
17
|
West TG, Hild G, Siththanandan VB, Webb MR, Corrie JE, Ferenczi MA. Time course and strain dependence of ADP release during contraction of permeabilized skeletal muscle fibers. Biophys J 2009; 96:3281-94. [PMID: 19383472 PMCID: PMC2718302 DOI: 10.1016/j.bpj.2009.01.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2008] [Revised: 12/17/2008] [Accepted: 01/08/2009] [Indexed: 10/20/2022] Open
Abstract
A phosphorylated, single cysteine mutant of nucleoside diphosphate kinase, labeled with N-[2-(iodoacetamido)ethyl]-7-diethylaminocoumarin-3-carboxamide (P approximately NDPK-IDCC), was used as a fluorescence probe for time-resolved measurement of changes in [MgADP] during contraction of single permeabilized rabbit psoas fibers. The dephosphorylation of the phosphorylated protein by MgADP occurs within the lattice environment of permeabilized fibers with a second-order rate constant at 12 degrees C of 10(5) M(-1) s(-1). This dephosphorylation is accompanied by a change in coumarin fluorescence. We report the time course of P approximately NDPK-IDCC dephosphorylation during the period of active isometric force redevelopment after quick release of fiber strain at pCa(2+) of 4.5. After a rapid length decrease of 0.5% was applied to the fiber, the extra NDPK-IDCC produced during force recovery, above the value during the approximately steady state of isometric contraction, was 2.7 +/- 0.6 microM and 4.7 +/- 1.5 microM at 12 and 20 degrees C, respectively. The rates of P approximately NDPK-IDCC dephosphorylation during force recovery were 28 and 50 s(-1) at 12 and 20 degrees C, respectively. The time courses of isometric force and P approximately NDPK-IDCC dephosphorylation were simulated using a seven-state reaction scheme. Relative isometric force was modeled by changes in the occupancy of strongly bound A.M.ADP.P(i) and A.M.ADP states. A strain-sensitive A.M.ADP isomerization step was rate-limiting (3-6 s(-1)) in the cross-bridge turnover during isometric contraction. At 12 degrees C, the A.M.ADP.P(i) and the pre- and postisomerization A.M.ADP states comprised 56%, 38%, and 7% of the isometric force-bearing AM states, respectively. At 20 degrees C, the force-bearing A.M.ADP.P(i) state was a lower proportion of the total force-bearing states (37%), whereas the proportion of postisomerization A.M.ADP states was higher (19%). The simulations suggested that release of cross-bridge strain caused rapid depopulation of the preisomerization A.M.ADP state and transient accumulation of MgADP in the postisomerization A.M.ADP state. Hence, the strain-sensitive isomerization of A.M.ADP seems to explain the rate of change of P approximately NDPK-IDCC dephosphorylation during force recovery. The temperature-dependent isometric distribution of myosin states is consistent with the previous observation of a small decrease in amplitude of the P(i) transient during force recovery at 20 degrees C and the current observation of an increase in amplitude of the ADP-sensitive NDPK-IDCC transient.
Collapse
Affiliation(s)
- Timothy G. West
- Imperial College London, Molecular Medicine Section, National Heart and Lung Institute, London, United Kingdom
| | - Gabor Hild
- Imperial College London, Molecular Medicine Section, National Heart and Lung Institute, London, United Kingdom
- Department of Biophysics, University of Pécs, Pécs, Hungary
| | - Verl B. Siththanandan
- Laboratory of Molecular Physiology, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - Martin R. Webb
- MRC National Institute for Medical Research, London, United Kingdom
| | - John E.T. Corrie
- MRC National Institute for Medical Research, London, United Kingdom
| | - Michael A. Ferenczi
- Imperial College London, Molecular Medicine Section, National Heart and Lung Institute, London, United Kingdom
| |
Collapse
|
18
|
Reichling LJ, Lebakken CS, Riddle SM, Vedvik KL, Robers MB, Kopp LM, Bruinsma R, Vogel KW. Pharmacological characterization of purified recombinant mTOR FRB-kinase domain using fluorescence-based assays. ACTA ACUST UNITED AC 2008; 13:238-44. [PMID: 18354135 DOI: 10.1177/1087057108314609] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The mammalian target of rapamycin (mTOR) is a serine/threonine kinase involved in nutrient sensing and cell growth and is a validated target for oncology and immunosuppression. Two modes of direct small-molecule inhibition of mTOR activity are known: targeting of the kinase active site and a unique mode in which the small molecule rapamycin, in complex with FKBP12 (the 12-kDa FK506 binding protein), binds to the FRB (FKBP12/rapamycin binding) domain of mTOR and inhibits kinase activity through a poorly defined mechanism. To facilitate the study of these processes, the authors have expressed and purified a truncated version of mTOR that contains the FRB and kinase domains and have developed homogeneous fluorescence-based assays to study mTOR activity. They demonstrate the utility of these assays in studies of active site-directed and FRB domain-directed mTOR inhibition. The results suggest that these assays can replace traditional radiometric or Western blot-based assays.
Collapse
|
19
|
Sainlos M, Imperiali B. Tools for investigating peptide-protein interactions: peptide incorporation of environment-sensitive fluorophores through SPPS-based 'building block' approach. Nat Protoc 2008; 2:3210-8. [PMID: 18079721 DOI: 10.1038/nprot.2007.443] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
This protocol presents the synthesis and peptide incorporation of environment-sensitive fluorescent amino acids derived from the dimethylamino-phthalimide family. The procedure uses anhydride precursors of 4-dimethylaminophthalimide (4-DMAP) or 6-dimethylaminonaphthalimide (6-DMN), whose syntheses are described in a related protocol by these authors. In this study, the corresponding fluorescent amino acids can be readily obtained in Fmoc-protected form for convenient use as building blocks in solid phase peptide synthesis (SPPS). The time required to complete the procedure depends on the size and the number of peptides targeted. Alternatively, the chromophores can be incorporated directly after SPPS via on-resin derivatization of peptides, which is an option described in a related protocol by these authors.
Collapse
Affiliation(s)
- Matthieu Sainlos
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139-4307, USA
| | | |
Collapse
|
20
|
Takagi Y, Yang Y, Fujiwara I, Jacobs D, Cheney RE, Sellers JR, Kovács M. Human myosin Vc is a low duty ratio, nonprocessive molecular motor. J Biol Chem 2008; 283:8527-37. [PMID: 18201966 DOI: 10.1074/jbc.m709150200] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Myosin Vc is the product of one of the three genes of the class V myosin found in vertebrates. It is widely found in secretory and glandular tissues, with a possible involvement in transferrin trafficking. Transient and steady-state kinetic studies of human myosin Vc were performed using a truncated, single-headed construct. Steady-state actin-activated ATPase measurements revealed a V(max) of 1.8 +/- 0.3 s(-1) and a K(ATPase) of 43 +/- 11 microm. Unlike previously studied vertebrate myosin Vs, the rate-limiting step in the actomyosin Vc ATPase pathway is the release of inorganic phosphate (~1.5 s(-1)), rather than the ADP release step (~12.0-16.0 s(-1)). Nevertheless, the ADP affinity of actomyosin Vc (K(d) = 0.25 +/- 0.02 microm) reflects a higher ADP affinity than seen in other myosin V isoforms. Using the measured kinetic rates, the calculated duty ratio of myosin Vc was approximately 10%, indicating that myosin Vc spends the majority of the actomyosin ATPase cycle in weak actin-binding states, unlike the other vertebrate myosin V isoforms. Consistent with this, a fluorescently labeled double-headed heavy meromyosin form showed no processive movements along actin filaments in a single molecule assay, but it did move actin filaments at a velocity of approximately 24 nm/s in ensemble assays. Kinetic simulations reveal that the high ADP affinity of actomyosin Vc may lead to elevations of the duty ratio of myosin Vc to as high as 64% under possible physiological ADP concentrations. This, in turn, may possibly imply a regulatory mechanism that may be sensitive to moderate changes in ADP concentration.
Collapse
Affiliation(s)
- Yasuharu Takagi
- Laboratory of Molecular Physiology, NHLBI, NIH, Bethesda, MD 20892-8015, USA
| | | | | | | | | | | | | |
Collapse
|
21
|
Spangler C, Schaeferling M, Wolfbeis OS. Fluorescent probes for microdetermination of inorganic phosphates and biophosphates. Mikrochim Acta 2007. [DOI: 10.1007/s00604-007-0897-6] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
22
|
Abstract
The elementary steps in complex biochemical reaction schemes (isomerization, dissociation, and association reactions) ultimately determine how fast any system can react in responding to incoming signals and in adapting to new conditions. Many of these steps have associated rate constants that result in subsecond responses to incoming signals or externally applied changes. This chapter is concerned with the techniques that have been developed to study such rapidly reacting systems in vitro and to determine the values of the rate constants for the individual steps. We focus principally on two classes of techniques: (1) flow techniques, in which two solutions are mixed within a few milliseconds and the ensuing reaction monitored over milliseconds to seconds, and (2) relaxation techniques, in which a small perturbation to an existing equilibrium is applied within a few microseconds and the response of the system is followed over microseconds to hundreds of milliseconds. These reactions are most conveniently monitored by recording the change in some optical signal, such as absorbance or fluorescence. We discuss the instrumentation that is (commercially) available to study fast reactions and describe a number of optical probes (chromophores) that can be used to monitor the changes. We discuss the experimental design appropriate for the different experimental techniques and reaction mechanisms, as well as the fundamental theoretical concepts behind the analysis of the data obtained.
Collapse
Affiliation(s)
- John F Eccleston
- Division of Physical Biochemistry, MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, United Kingdom
| | | | | |
Collapse
|
23
|
Webb MR. Development of fluorescent biosensors for probing the function of motor proteins. MOLECULAR BIOSYSTEMS 2007; 3:249-56. [PMID: 17372653 DOI: 10.1039/b614154d] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Biosensors are becoming widely used both in basic research and in screening assays and reagentless sensors with fluorescent reporter groups attached to proteins form one class. This article describes the development of sensors for two small molecules, driven in particular by the need for high sensitivity and time resolution to probe mechanistic aspects of ATP-coupled motor proteins. The biosensors are for the products of the ATPase reaction, ADP and inorganic phosphate. The interplay between the possibilities for design and understanding the mechanism of the signal are discussed. Examples are described of how these sensors have been applied to understanding myosin and helicase motors.
Collapse
Affiliation(s)
- Martin R Webb
- MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London, UK NW7 1AA.
| |
Collapse
|
24
|
Klumpp M, Boettcher A, Becker D, Meder G, Blank J, Leder L, Forstner M, Ottl J, Mayr LM. Readout Technologies for Highly Miniaturized Kinase Assays Applicable to High-Throughput Screening in a 1536-Well Format. ACTA ACUST UNITED AC 2006; 11:617-33. [PMID: 16760365 DOI: 10.1177/1087057106288444] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
This article discusses the development of homogeneous, miniaturized assays for the identification of novel kinase inhibitors from very large compound collections. In particular, the suitability of time-resolved fluorescence resonance energy transfer (TR-RET) based on phospho-specific antibodies, an antibody-independent fluorescence polarization (FP) approach using metal-coated beads (IMAP™ technology), and the determination of adenosine triphosphate consumption through chemiluminescence is evaluated. These readouts are compared with regard to assay sensitivity, compound interference, reagent consumption, and performance in a 1536-well format, and practical considerations for their application in primary screening or in the identification of kinase substrates are discussed. All of the tested technologies were found to be suitable for miniaturized high-throughput screening (HTS) in principle, but each of them has distinct limitations and advantages. Therefore, the target-specific selection of the most appropriate readout technology is recommended to ensure maximal relevance of HTS campaigns.
Collapse
Affiliation(s)
- Martin Klumpp
- Novartis Institute for Biomedical Research, Basel, Switzerland.
| | | | | | | | | | | | | | | | | |
Collapse
|
25
|
West TG, Ferenczi MA, Woledge RC, Curtin NA. Influence of ionic strength on the time course of force development and phosphate release by dogfish muscle fibres. J Physiol 2005; 567:989-1000. [PMID: 16037082 PMCID: PMC1474231 DOI: 10.1113/jphysiol.2005.087106] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
We measured the effects of ionic strength (IS), 200 (standard) and 400 mmol l(-1) (high), on force and ATP hydrolysis during isometric contractions of permeabilized white fibres from dogfish myotomal muscle at their physiological temperature, 12 degrees C. One goal was to test the validity of our kinetic scheme that accounts for energy release, work production and ATP hydrolysis. Fibres were activated by flash photolysis of the P(3)-1-(2 nitrophenyl) ethyl ester of ATP (NPE-caged ATP), and time-resolved phosphate (P(i)) release was detected with the fluorescent protein MDCC-PBP, N-(2[1-maleimidyl]ethyl)-7-diethylamino-coumarin-3-carboxamide phosphate binding protein. High IS slowed the transition from rest to contraction, but as the fibres approached the isometric force plateau they showed little IS sensitivity. By 0.5 s of contraction, the force and the rate of P(i) release at standard and high IS values were not significantly different. A five-step reaction mechanism was used to account for the observed time courses of force and P(i) release in all conditions explored here. Only the rate constants for reactions of ATP, ADP and P(i) with the contractile proteins varied with IS, thus suggesting that the actin-myosin interactions are largely non-ionic. Our reaction scheme also fits previous results for intact fibres.
Collapse
Affiliation(s)
- Timothy G West
- Imperial College London, Division of Biomedical Sciences, Biological Nanoscience, UK.
| | | | | | | |
Collapse
|
26
|
Tóth J, Kovács M, Wang F, Nyitray L, Sellers JR. Myosin V from Drosophila reveals diversity of motor mechanisms within the myosin V family. J Biol Chem 2005; 280:30594-603. [PMID: 15980429 DOI: 10.1074/jbc.m505209200] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Myosin V is the best characterized vesicle transporter in vertebrates, but it has been unknown as to whether all members of the myosin V family share a common, evolutionarily conserved mechanism of action. Here we show that myosin V from Drosophila has a strikingly different motor mechanism from that of vertebrate myosin Va, and it is a nonprocessive, ensemble motor. Our steady-state and transient kinetic measurements on single-headed constructs reveal that a single Drosophila myosin V molecule spends most of its mechanochemical cycle time detached from actin, therefore it has to function in processive units that comprise several molecules. Accordingly, in in vitro motility assays, double-headed Drosophila myosin V requires high surface concentrations to exhibit a continuous translocation of actin filaments. Our comparison between vertebrate and fly myosin V demonstrates that the well preserved function of myosin V motors in cytoplasmic transport can be accomplished by markedly different underlying mechanisms.
Collapse
Affiliation(s)
- Judit Tóth
- Laboratory of Molecular Physiology, NHLBI, National Institutes of Health, Bethesda, Maryland 20892-1762, USA
| | | | | | | | | |
Collapse
|
27
|
Hutter MC, Helms V. The mechanism of phosphorylation of natural nucleosides and anti-HIV analogues by nucleoside diphosphate kinase is independent of their sugar substituents. Chembiochem 2002; 3:643-51. [PMID: 12324998 DOI: 10.1002/1439-7633(20020703)3:7<643::aid-cbic643>3.0.co;2-l] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The reaction mechanism of the phosphoryl transfer catalyzed by dinucleoside diphosphate kinase from Dictyostelium discoideum is investigated by semiempirical AM1 molecular orbital computation of an active site model system on the basis of various X-ray crystallographic structures. The computational results suggest that the phosphoryl transfer from adenosine triphosphate to the His122 residue is accompanied by the simultaneous shift of a proton from the histidine residue to one of the oxygen atoms of the gamma phosphate group. This involves a doubly protonated His122 residue whilst this residue is neutral in its ternary complex with ADP and the transition state analogue AlF(3). The proposed mechanism is thus analogous to that of phosphoryl transfer by cyclic adenosine monophosphate dependent protein kinase and uridine/cytidine monophosphate kinase as found in our earlier work and clarifies the role of the ribose 3'-OH group. Furthermore, the energetics of phosphoryl transfer onto other nucleoside analogues such as 3'-azido-3'-deoxythymidine-diphosphate and 2',3'-dideoxy-2',3'-didehydro-thymidine-diphosphate are investigated. The calculated reaction barriers for the phosphorylation of the diphosphates by the enzyme are all within a range of 13.1 kJ mol(-1), which suggests that variations in the activation energies alone cannot account for the experimentally observed differences in enzymatic activity. Consequences for the design of new anti-HIV nucleoside analogues are discussed. Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2268/2002/f360_s.pdf or from the author.
Collapse
Affiliation(s)
- Michael C Hutter
- Theoretical Biophysics Max-Planck-Institute of Biophysics Kennedyallee 70, 60596 Frankfurt, Germany
| | | |
Collapse
|