Application of Fragment Screening by X-ray Crystallography to the Discovery of Aminopyridines as Inhibitors of β-Secretase§

2007 ◽  
Vol 50 (6) ◽  
pp. 1124-1132 ◽  
Author(s):  
Miles Congreve ◽  
David Aharony ◽  
Jeffrey Albert ◽  
Owen Callaghan ◽  
James Campbell ◽  
...  
2018 ◽  
Vol 19 (11) ◽  
pp. 3664 ◽  
Author(s):  
Ali Munawar ◽  
Steven Beelen ◽  
Ahmad Munawar ◽  
Eveline Lescrinier ◽  
Sergei Strelkov

The flavivirus family contains several important human pathogens, such as Zika virus (ZIKV), dengue, West Nile, and Yellow Fever viruses, that collectively lead to a large, global disease burden. Currently, there are no approved medicines that can target these viruses. The sudden outbreak of ZIKV infections in 2015–2016 posed a serious threat to global public health. While the epidemic has receded, persistent reservoirs of ZIKV infection can cause reemergence. Here, we have used X-ray crystallography-based screening to discover two novel sites on ZIKV NS3 helicase that can bind drug-like fragments. Both sites are structurally conserved in other flaviviruses, and mechanistically significant. The binding poses of four fragments, two for each of the binding sites, were characterized at atomic precision. Site A is a surface pocket on the NS3 helicase that is vital to its interaction with NS5 polymerase and formation of the flaviviral replication complex. Site B corresponds to a flexible, yet highly conserved, allosteric site at the intersection of the three NS3 helicase domains. Saturation transfer difference nuclear magnetic resonance (NMR) experiments were additionally used to evaluate the binding strength of the fragments, revealing dissociation constants (KD) in the lower mM range. We conclude that the NS3 helicase of flaviviruses is a viable drug target. The data obtained open opportunities towards structure-based design of first-in-class anti-ZIKV compounds, as well as pan-flaviviral therapeutics.


Author(s):  
Douglas R. Davies ◽  
Darren W. Begley ◽  
Robert C. Hartley ◽  
Bart L. Staker ◽  
Lance J. Stewart

2012 ◽  
Vol 18 (2) ◽  
pp. 147-159 ◽  
Author(s):  
Jerome Wielens ◽  
Stephen J. Headey ◽  
David I. Rhodes ◽  
Roger J. Mulder ◽  
Olan Dolezal ◽  
...  

Fragment screening is becoming widely accepted as a technique to identify hit compounds for the development of novel lead compounds. In neighboring laboratories, we have recently, and independently, performed a fragment screening campaign on the HIV-1 integrase core domain (IN) using similar commercially purchased fragment libraries. The two campaigns used different screening methods for the preliminary identification of fragment hits; one used saturation transfer difference nuclear magnetic resonance spectroscopy (STD-NMR), and the other used surface plasmon resonance (SPR) spectroscopy. Both initial screens were followed by X-ray crystallography. Using the STD-NMR/X-ray approach, 15 IN/fragment complexes were identified, whereas the SPR/X-ray approach found 6 complexes. In this article, we compare the approaches that were taken by each group and the results obtained, and we look at what factors could potentially influence the final results. We find that despite using different approaches with little overlap of initial hits, both approaches identified binding sites on IN that provided a basis for fragment-based lead discovery and further lead development. Comparison of hits identified in the two studies highlights a key role for both the conditions under which fragment binding is measured and the criteria selected to classify hits.


2015 ◽  
Vol 71 (a1) ◽  
pp. s258-s258
Author(s):  
Nicholas M. Pearce ◽  
Sebastian Kelm ◽  
Jiye Shi ◽  
Charlotte M. Deane ◽  
Frank von Delft

Author(s):  
James H. Thorpe ◽  
Ian D. Wall ◽  
Robert H. Sinnamon ◽  
Amy N. Taylor ◽  
Robert A. Stavenger

Direct soaking of protein crystals with small-molecule fragments grouped into complementary clusters is a useful technique when assessing the potential of a new crystal system to support structure-guided drug discovery. It provides a robustness check prior to any extensive crystal screening, a double check for assay binding cutoffs and structural data for binding pockets that may or may not be picked out in assay measurements. The structural output from this technique for three novel fragment molecules identified to bind to the antibacterial target Acinetobacter baumannii undecaprenyl pyrophosphate synthase are reported, and the different physicochemical requirements of a successful antibiotic are compared with traditional medicines.


2017 ◽  
Vol 61 (5) ◽  
pp. 465-473 ◽  
Author(s):  
Daniel Shiu-Hin Chan ◽  
Andrew J. Whitehouse ◽  
Anthony G. Coyne ◽  
Chris Abell

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.


2015 ◽  
Vol 21 (4) ◽  
pp. 414-421 ◽  
Author(s):  
Pawel Linke ◽  
Kwame Amaning ◽  
Melanie Maschberger ◽  
Francois Vallee ◽  
Valerie Steier ◽  
...  

Fragment-based lead discovery has proved to be an effective alternative to high-throughput screenings in identifying chemical matter that can be developed into robust lead compounds. The search for optimal combinations of biophysical techniques that can correctly and efficiently identify and quantify binding can be challenging due to the physicochemical properties of fragments. In order to minimize the time and costs of screening, optimal combinations of biophysical techniques with maximal information content, sensitivity, and robustness are needed. Here we describe an approach utilizing automated microscale thermophoresis (MST) affinity screening to identify fragments active against MEK1 kinase. MST identified multiple hits that were confirmed by X-ray crystallography but not detected by orthogonal methods. Furthermore, MST also provided information about ligand-induced aggregation and protein denaturation. The technique delivered a large number of binders while reducing experimentation time and sample consumption, demonstrating the potential of MST to execute and maximize the efficacy of fragment screening campaigns.


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