Label-Free Inhibition in Solution Assays for Fragment Screening

2015 ◽  
pp. 119-132
Author(s):  
Stefan Geschwindner
Keyword(s):  
Label Free ◽  
Fragment Screening

scholarly journals Label-Free Primary Screening and Affinity Ranking of Fragment Libraries Using Parallel Analysis of Protein Panels

2008 ◽  
Vol 13 (3) ◽  
pp. 202-209 ◽  
Author(s):  
Markku D. Hämäläinen ◽  
Andrei Zhukov ◽  
Maria Ivarsson ◽  
Tomas Fex ◽  
Johan Gottfries ◽  
...  
Keyword(s):  
Binding Site ◽  
Parallel Analysis ◽  
Label Free ◽  
Glutathione S Transferase ◽  
Chip Surface ◽  
Fragment Screening ◽  
Fragment Library ◽  
Direct Binding ◽  
Resonance Detection ◽  
Fragment Libraries

The authors present fragment screening data obtained using a label-free parallel analysis approach where the binding of fragment library compounds to 4 different target proteins can be screened simultaneously using surface plasmon resonance detection. They suggest this method as a first step in fragment screening to identify and select binders, reducing the demanding requirements on subsequent X-ray or nuclear magnetic resonance studies, and as a valuable “clean-up” tool to eliminate unwanted promiscuous binders from libraries. A small directed fragment library of known thrombin binders and a general 500-compound fragment library were used in this study. Thrombin, blocked thrombin, carbonic anhydrase, and glutathione-S-transferase were immobilized on the sensor chip surface, and the direct binding of the fragments was studied in real time. Only 12 µg of each protein is needed for screening of a 3000-compound fragment library. For screening, a binding site-blocked target as reference facilitates the identification of binding site-selective hits and the signals from other reference proteins for the elimination of false positives. The scope and limitations of this screening approach are discussed for both target-directed and general fragment libraries. ( Journal of Biomolecular Screening 2008:202-209)

scholarly journals Mass spectrometry for fragment screening

2017 ◽  
Vol 61 (5) ◽  
pp. 465-473 ◽  
Author(s):  
Daniel Shiu-Hin Chan ◽  
Andrew J. Whitehouse ◽  
Anthony G. Coyne ◽  
Chris Abell
Keyword(s):  
Drug Discovery ◽  
High Sensitivity ◽  
Titration Calorimetry ◽  
Label Free ◽  
X Ray ◽  
X Ray Crystallography ◽  
Fragment Screening ◽  
Differential Scanning Fluorimetry ◽  
Biophysical Techniques

Fragment-based approaches in chemical biology and drug discovery have been widely adopted worldwide in both academia and industry. Fragment hits tend to interact weakly with their targets, necessitating the use of sensitive biophysical techniques to detect their binding. Common fragment screening techniques include differential scanning fluorimetry (DSF) and ligand-observed NMR. Validation and characterization of hits is usually performed using a combination of protein-observed NMR, isothermal titration calorimetry (ITC) and X-ray crystallography. In this context, MS is a relatively underutilized technique in fragment screening for drug discovery. MS-based techniques have the advantage of high sensitivity, low sample consumption and being label-free. This review highlights recent examples of the emerging use of MS-based techniques in fragment screening.

scholarly journals Label Free Fragment Screening Using Surface Plasmon Resonance as a Tool for Fragment Finding – Analyzing Parkin, a Difficult CNS Target

PLoS ONE ◽  
2013 ◽  
Vol 8 (7) ◽  
pp. e66879 ◽  
Author(s):  
Karin Regnström ◽  
Jiangli Yan ◽  
Lan Nguyen ◽  
Kari Callaway ◽  
Yanli Yang ◽  
...  
Keyword(s):  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Label Free ◽  
Fragment Screening

scholarly journals Label-free DNA-methylation detection by direct ds-DNA fragment screening using poly-purine hairpins

2018 ◽  
Vol 120 ◽  
pp. 47-54 ◽  
Author(s):  
César S. Huertas ◽  
Anna Aviñó ◽  
Cristina Kurachi ◽  
Albert Piqué ◽  
Juan Sandoval ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Label Free ◽  
Fragment Screening ◽  
Free Dna ◽  
Dna Fragment

Label-free, mass-sensitive single-molecule imaging using interferometric scattering microscopy

2020 ◽  
Author(s):  
Nikolas Hundt
Keyword(s):  
Single Molecule ◽  
Cellular Systems ◽  
Single Molecule Imaging ◽  
Label Free ◽  
Measurement Sensitivity ◽  
Mass Distributions ◽  
Quantitative Measurements ◽  
Contrast Mechanism ◽  
Cellular Components ◽  
Scattering Signal

Abstract Single-molecule imaging has mostly been restricted to the use of fluorescence labelling as a contrast mechanism due to its superior ability to visualise molecules of interest on top of an overwhelming background of other molecules. Recently, interferometric scattering (iSCAT) microscopy has demonstrated the detection and imaging of single biomolecules based on light scattering without the need for fluorescent labels. Significant improvements in measurement sensitivity combined with a dependence of scattering signal on object size have led to the development of mass photometry, a technique that measures the mass of individual molecules and thereby determines mass distributions of biomolecule samples in solution. The experimental simplicity of mass photometry makes it a powerful tool to analyse biomolecular equilibria quantitatively with low sample consumption within minutes. When used for label-free imaging of reconstituted or cellular systems, the strict size-dependence of the iSCAT signal enables quantitative measurements of processes at size scales reaching from single-molecule observations during complex assembly up to mesoscopic dynamics of cellular components and extracellular protrusions. In this review, I would like to introduce the principles of this emerging imaging technology and discuss examples that show how mass-sensitive iSCAT can be used as a strong complement to other routine techniques in biochemistry.

A microfluidic device with integrated impedance detection for λ-DNA

2003 ◽  
Vol 773 ◽  
Author(s):  
Myung-Il Park ◽  
Jonging Hong ◽  
Dae Sung Yoon ◽  
Chong-Ook Park ◽  
Geunbae Im
Keyword(s):  
Microfluidic Device ◽  
Electrochemical Impedance ◽  
Direct Detection ◽  
Full Potential ◽  
Label Free ◽  
Buffer Solution ◽  
Detection Systems ◽  
Significant Difference ◽  
Detection Of Biomolecules ◽  
Impedance Magnitude

AbstractThe large optical detection systems that are typically utilized at present may not be able to reach their full potential as portable analysis tools. Accurate, early, and fast diagnosis for many diseases requires the direct detection of biomolecules such as DNA, proteins, and cells. In this research, a glass microchip with integrated microelectrodes has been fabricated, and the performance of electrochemical impedance detection was investigated for the biomolecules. We have used label-free λ-DNA as a sample biomolecule. By changing the distance between microelectrodes, the significant difference between DW and the TE buffer solution is obtained from the impedance-frequency measurements. In addition, the comparison for the impedance magnitude of DW, the TE buffer, and λ-DNA at the same distance was analyzed.

Covalent-Fragment Screening of Brd4 Identifies a Ligandable Site Orthogonal to the Acetyl-Lysine Binding Sites

2019 ◽  
Author(s):  
Michael Olp ◽  
Daniel Sprague ◽  
Stefan Kathman ◽  
Ziyang Xu ◽  
Alexandar Statsyuk ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Binding Site ◽  
Binding Sites ◽  
Computational Prediction ◽  
Chemical Probes ◽  
Computational Docking ◽  
Fragment Screening ◽  
Covalent Inhibitors ◽  
Bet Protein ◽  
Proof Of Principle

<p>Brd4, a member of the bromodomain and extraterminal domain (BET) family, has emerged as a promising epigenetic target in cancer and inflammatory disorders. All reported BET family ligands bind within the bromodomain acetyl-lysine binding sites and competitively inhibit BET protein interaction with acetylated chromatin. Alternative chemical probes that act orthogonally to the highly-conserved acetyl-lysine binding sites may exhibit selectivity within the BET family and avoid recently reported toxicity in clinical trials of BET bromodomain inhibitors. Here, we report the first identification of a ligandable site on a bromodomain outside the acetyl-lysine binding site. Inspired by our computational prediction of hotspots adjacent to non-homologous cysteine residues within the <i>C</i>-terminal Brd4 bromodomain (Brd4-BD2), we performed a mid-throughput mass spectrometry screen to identify cysteine-reactive fragments that covalently and selectively modify Brd4. Subsequent mass spectrometry, NMR and computational docking analyses of electrophilic fragment hits revealed a novel ligandable site near Cys356 that is unique to Brd4 among all human bromodomains. This site is orthogonal to the Brd4-BD2 acetyl-lysine binding site as Cys356 modification did not impact binding of the pan-BET bromodomain inhibitor JQ1 in fluorescence polarization assays. Finally, we tethered covalent fragments to JQ1 and performed NanoBRET assays to provide proof of principle that this orthogonal site can be covalently targeted in intact human cells. Overall, we demonstrate the potential of targeting sites orthogonal to bromodomain acetyl-lysine binding sites to develop bivalent and covalent inhibitors that displace Brd4 from chromatin.</p>

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