The structure of chitinases and prospects for structure-based drug design

1995 ◽  
Vol 73 (S1) ◽  
pp. 1142-1146 ◽  
Author(s):  
Jon D. Robertus ◽  
P. John Hart ◽  
Arthur F. Monzingo ◽  
Edward Marcotte ◽  
Thomas Hollis
Keyword(s):  
Drug Design ◽  
Small Molecules ◽  
Mechanism Of Action ◽  
Active Site ◽  
Antifungal Agents ◽  
Structure Based Drug Design ◽  
X Ray ◽  
Class Ii Chitinase ◽  
Transition State Geometry ◽  
Chitinase Inhibitors

Many fungi, including pathogenic strains, require proper chitin metabolism to assure normal cell wall replication. Chitinase hydrolyzes chitin; inhibition of endogenous chitinases or application of extracellular chitinases can disrupt fungal division. It is possible that chitinase inhibitors could be used as antifungal agents. We have solved the X-ray structure of a class II chitinase from barley and proposed a mechanism of action. The enzyme has a structural core similar to lysozyme and probably acts in a similar catalytic manner. The enzyme structure can, in principle, be used to identify small molecules that will bind avidly to the active site and act as inhibitors. Those inhibitors that embody transition state geometry are likely to be particularly effective. Key words: chitinase, mechanism of action, drug design.

scholarly journals Crystallographic and electrophilic fragment screening of the SARS-CoV-2 main protease

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Alice Douangamath ◽  
Daren Fearon ◽  
Paul Gehrtz ◽  
Tobias Krojer ◽  
Petra Lukacik ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Drug Design ◽  
Active Site ◽  
Large Scale ◽  
Structure Based Drug Design ◽  
Dimer Interface ◽  
X Ray ◽  
Fragment Screening ◽  
Viral Proteases ◽  
Main Protease

Abstract COVID-19, caused by SARS-CoV-2, lacks effective therapeutics. Additionally, no antiviral drugs or vaccines were developed against the closely related coronavirus, SARS-CoV-1 or MERS-CoV, despite previous zoonotic outbreaks. To identify starting points for such therapeutics, we performed a large-scale screen of electrophile and non-covalent fragments through a combined mass spectrometry and X-ray approach against the SARS-CoV-2 main protease, one of two cysteine viral proteases essential for viral replication. Our crystallographic screen identified 71 hits that span the entire active site, as well as 3 hits at the dimer interface. These structures reveal routes to rapidly develop more potent inhibitors through merging of covalent and non-covalent fragment hits; one series of low-reactivity, tractable covalent fragments were progressed to discover improved binders. These combined hits offer unprecedented structural and reactivity information for on-going structure-based drug design against SARS-CoV-2 main protease.

scholarly journals Crystallographic and electrophilic fragment screening of the SARS-CoV-2 main protease

2020 ◽  
Author(s):  
Alice Douangamath ◽  
Daren Fearon ◽  
Paul Gehrtz ◽  
Tobias Krojer ◽  
Petra Lukacik ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Drug Design ◽  
Active Site ◽  
Large Scale ◽  
Structure Based Drug Design ◽  
Dimer Interface ◽  
X Ray ◽  
Fragment Screening ◽  
Viral Proteases ◽  
Main Protease

SummaryCOVID-19, caused by SARS-CoV-2, lacks effective therapeutics. Additionally, no antiviral drugs or vaccines were developed against the closely related coronavirus, SARS-CoV-1 or MERS-CoV, despite previous zoonotic outbreaks. To identify starting points for such therapeutics, we performed a large-scale screen of electrophile and non-covalent fragments through a combined mass spectrometry and X-ray approach against the SARS-CoV-2 main protease, one of two cysteine viral proteases essential for viral replication. Our crystallographic screen identified 71 hits that span the entire active site, as well as 3 hits at the dimer interface. These structures reveal routes to rapidly develop more potent inhibitors through merging of covalent and non-covalent fragment hits; one series of low-reactivity, tractable covalent fragments was progressed to discover improved binders. These combined hits offer unprecedented structural and reactivity information for on-going structure-based drug design against SARS-CoV-2 main protease.

scholarly journals Toward the Identification of Potential α-Ketoamide Covalent Inhibitors for SARS-CoV-2 Main Protease: Fragment-Based Drug Design and MM-PBSA Calculations

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 1004
Author(s):  
Mahmoud A. El Hassab ◽  
Mohamed Fares ◽  
Mohammed K. Abdel-Hamid Amin ◽  
Sara T. Al-Rashood ◽  
Amal Alharbi ◽  
...  
Keyword(s):  
Drug Design ◽  
Active Site ◽  
Binding Free Energy ◽  
Stable Complex ◽  
Active Site Residues ◽  
Structure Based Drug Design ◽  
Enzyme Active Site ◽  
Potential Inhibitor ◽  
Main Protease ◽  
Covalent Docking

Since December 2019, the world has been facing the outbreak of the SARS-CoV-2 pandemic that has infected more than 149 million and killed 3.1 million people by 27 April 2021, according to WHO statistics. Safety measures and precautions taken by many countries seem insufficient, especially with no specific approved drugs against the virus. This has created an urgent need to fast track the development of new medication against the virus in order to alleviate the problem and meet public expectations. The SARS-CoV-2 3CL main protease (Mpro) is one of the most attractive targets in the virus life cycle, which is responsible for the processing of the viral polyprotein and is a key for the ribosomal translation of the SARS-CoV-2 genome. In this work, we targeted this enzyme through a structure-based drug design (SBDD) protocol, which aimed at the design of a new potential inhibitor for Mpro. The protocol involves three major steps: fragment-based drug design (FBDD), covalent docking and molecular dynamics (MD) simulation with the calculation of the designed molecule binding free energy at a high level of theory. The FBDD step identified five molecular fragments, which were linked via a suitable carbon linker, to construct our designed compound RMH148. The mode of binding and initial interactions between RMH148 and the enzyme active site was established in the second step of our protocol via covalent docking. The final step involved the use of MD simulations to test for the stability of the docked RMH148 into the Mpro active site and included precise calculations for potential interactions with active site residues and binding free energies. The results introduced RMH148 as a potential inhibitor for the SARS-CoV-2 Mpro enzyme, which was able to achieve various interactions with the enzyme and forms a highly stable complex at the active site even better than the co-crystalized reference.

scholarly journals Modeling and synthesis of antiplasmodial chromones, chromanones and chalcones based on natural products of Kenya

2018 ◽  
Vol 16 (1) ◽  
pp. 8-21
Author(s):  
MANYIM SCOLASTICA ◽  
ALBERT J. NDAKALA ◽  
SOLOMON DERESE
Keyword(s):  
Natural Products ◽  
Drug Design ◽  
Active Site ◽  
Docking Studies ◽  
Moderate Activity ◽  
Vigorous Activity ◽  
Structure Based Drug Design ◽  
Web Based ◽  
Ic50 Values ◽  
Accessible Form

Scolastica M, Ndakala AJ, Derese S. 2018. Modeling and synthesis of antiplasmodial chromones, chromanones and chalcones based on natural products of Kenya. Biofarmasi J Nat Prod Biochem 16: 8-21. Despite numerous research that has been done on plants of Kenya resulting in the isolation of thousands of natural products, data on these natural products are not systematically organized in a readily accessible form. This has urged the construction of a web-based database of natural products of Kenya. The database is named Mitishamba and is hosted at http://mitishamba.uonbi.ac.ke. The Mitishamba database was queried for chromones, chromanones, and chalcones that were subjected to structure-based drug design using Fred (OpenEye) docking utility program with 1TV5 PDB structure of the PfDHODH receptor to identify complex of ligands that bind with the active site. Ligand-based drug design (Shape and electrostatics comparison) was also done on the ligands against query A77 1726 (38) (the ligand that co-crystallized with PfDHODH receptor) using ROCS and EON programs, respectively, of OpenEye suite. There was a substantial similarity among the top performing ligands in the docking studies with shape and electrostatic comparison that led to the identification of compounds of interest which were targeted for synthesis and antiplasmodial assay. In this study, a chromanone (7-hydroxy-2-(4-methoxyphenyl) chroman-4-one (48)) and two intermediate chalcones (2',4'-dihydroxy-4-methoxychalcone (45) and 2’,4’-dihydroxy-4-chlorochalcone (47)), were synthesized and subjected to antiplasmodial assay. Among these substances, 45 showed vigorous activity, whereas 47 and 48 had moderate activity against the chloroquine resistant K1 strain of P. falciparum with IC50 values of 4.56±1.66, 17.62 ± 5.94 and 18.01 ±1.66 µg/ml, respectively. Since the synthesized compounds showed antiplasmodial potential, there is a need for further computational refinement of these compounds to optimize their antiplasmodial activity.

scholarly journals The critical role of QM/MM X-ray refinement and accurate tautomer/protomer determination in structure-based drug design

2020 ◽  
Author(s):  
Oleg Y. Borbulevych ◽  
Roger I. Martin ◽  
Lance M. Westerhoff
Keyword(s):  
Drug Design ◽  
Critical Role ◽  
Pharmaceutical Research ◽  
Energy Functional ◽  
Structural Refinement ◽  
Structure Based Drug Design ◽  
X Ray ◽  
X Ray Crystallography ◽  
Refinement Method ◽  
The Impact

Abstract Conventional protein:ligand crystallographic refinement uses stereochemistry restraints coupled with a rudimentary energy functional to ensure the correct geometry of the model of the macromolecule—along with any bound ligand(s)—within the context of the experimental, X-ray density. These methods generally lack explicit terms for electrostatics, polarization, dispersion, hydrogen bonds, and other key interactions, and instead they use pre-determined parameters (e.g. bond lengths, angles, and torsions) to drive structural refinement. In order to address this deficiency and obtain a more complete and ultimately more accurate structure, we have developed an automated approach for macromolecular refinement based on a two layer, QM/MM (ONIOM) scheme as implemented within our DivCon Discovery Suite and "plugged in" to two mainstream crystallographic packages: PHENIX and BUSTER. This implementation is able to use one or more region layer(s), which is(are) characterized using linear-scaling, semi-empirical quantum mechanics, followed by a system layer which includes the balance of the model and which is described using a molecular mechanics functional. In this work, we applied our Phenix/DivCon refinement method—coupled with our XModeScore method for experimental tautomer/protomer state determination—to the characterization of structure sets relevant to structure-based drug design (SBDD). We then use these newly refined structures to show the impact of QM/MM X-ray refined structure on our understanding of function by exploring the influence of these improved structures on protein:ligand binding affinity prediction (and we likewise show how we use post-refinement scoring outliers to inform subsequent X-ray crystallographic efforts). Through this endeavor, we demonstrate a computational chemistry ↔ structural biology (X-ray crystallography) "feedback loop" which has utility in industrial and academic pharmaceutical research as well as other allied fields.

The Complex of a Bivalent Derivative of Galanthamine withTorpedoAcetylcholinesterase Displays Drastic Deformation of the Active-Site Gorge:  Implications for Structure-Based Drug Design

2004 ◽  
Vol 126 (47) ◽  
pp. 15405-15411 ◽  
Author(s):  
Harry M. Greenblatt ◽  
Catherine Guillou ◽  
Daniel Guénard ◽  
Anat Argaman ◽  
Simone Botti ◽  
...  
Keyword(s):  
Drug Design ◽  
Active Site ◽  
Structure Based Drug Design

scholarly journals Solving an X-Ray Structure of a Bio-Artificial Neurotransmitter Receptor Designed for the Naked-Eye Recognition of Dopamine

2020 ◽  
Author(s):  
Thibaud Rossel ◽  
Bing Zhang ◽  
Raphael Gobat
Keyword(s):  
Chemical Synthesis ◽  
Small Molecules ◽  
Active Site ◽  
Chemical Sensor ◽  
Selective Detection ◽  
Neurotransmitter Receptor ◽  
X Ray ◽  
Naked Eye ◽  
Coordination Spheres ◽  
Eye Recognition

The literature is constellated with a wide variety of chemosensors against a plethora of analytes. This seminal library is used to inspire chemists to improve them using chemical synthesis. However, their optimization via chemical synthesis is a difficult task which takes time without the guarantee of final success.We show here that combinatorial chemistry,the use of first and second coordination spheres and the displacement of indicators united within a protein cavity offers an easy-to-assemble colorimetric bio-chemical sensor. It consists only of commercial chemicals. This colorimetric sensor is highly modular, cheap and evolvable. Its X-ray structure reveals the composition of its active site. This allows to design it rationally for the recognition of dopamine with the naked eye. Our bio-sensor therefore resembles a biological receptor for the recognition of neurotransmitters. Its immediate high adaptability and ability to be evolved can be useful for the selective detection of a wide variety of analytes going from small molecules to microorganisms. This discovery therefore makes it possible to dream of new biotechnological or new immunotherapeutic applications.<br>

scholarly journals Structure-Based Drug Design of an Inhibitor of the SARS-CoV-2 (COVID-19) Main Protease Using Free Software: A Tutorial for Students and Scientists

2020 ◽  
Author(s):  
Sheng Zhang ◽  
Maj Krumberger ◽  
Michael A. Morris ◽  
Chelsea Marie T. Parrocha ◽  
James H. Griffin ◽  
...  
Keyword(s):  
Drug Design ◽  
Cyclic Peptide ◽  
Free Software ◽  
New Drugs ◽  
Peptide Inhibitor ◽  
Drug Candidate ◽  
Crystallographic Structure ◽  
Structure Based Drug Design ◽  
X Ray ◽  
Main Protease

This paper describes the structure-based design of a preliminary drug candidate against COVID-19 using free software and publicly available X-ray crystallographic structures. The goal of this tutorial is to disseminate skills in structure-based drug design and to allow others to unleash their own creativity to design new drugs to fight the current pandemic. The tutorial begins with the X-ray crystallographic structure of the main protease (M<sup>pro</sup>) of the SARS coronavirus (SARS-CoV) bound to a peptide substrate and then uses the UCSF Chimera software to modify the substrate to create a cyclic peptide inhibitor within the M<sup>pro</sup> active site. Finally, the tutorial uses the molecular docking software AutoDock Vina to show the interaction of the cyclic peptide inhibitor with both SARS-CoV M<sup>pro</sup> and the highly homologous SARS-CoV-2 M<sup>pro</sup>. The supporting information (supplementary material) provides an illustrated step-by-step protocol, as well as a video showing the inhibitor design process, to help readers design their own drug candidates for COVID-19 and the coronaviruses that will cause future pandemics. An accompanying preprint in bioRxiv [https://doi.org/10.1101/2020.08.03.234872] describes the synthesis of the cyclic peptide and the experimental validation as an inhibitor of SARS-CoV-2 M<sup>pro</sup>.

scholarly journals Computational Identification of Stearic Acid as a Potential PDK1 Inhibitor and In Vitro Validation of Stearic Acid as Colon Cancer Therapeutic in Combination with 5-Fluorouracil

2021 ◽  
Vol 20 ◽  
pp. 117693512110659
Author(s):  
Jonathan Mitchel ◽  
Pratima Bajaj ◽  
Ketki Patil ◽  
Austin Gunnarson ◽  
Emilie Pourchet ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Drug Design ◽  
Stearic Acid ◽  
Mechanism Of Action ◽  
Colorectal Adenocarcinoma ◽  
Metabolic Reprogramming ◽  
Colorectal Cancers ◽  
Structure Based Drug Design ◽  
Computational Structure ◽  
Efficacious Treatment

Background: Colorectal cancer is the third largest cause of cancer-related mortality worldwide. Although current treatments with chemotherapeutics have allowed for management of colorectal cancer, additional novel treatments are essential. Intervening with the metabolic reprogramming observed in cancers called “Warburg Effect,” is one of the novel strategies considered to combat cancers. In the metabolic reprogramming pathway, pyruvate dehydrogenase kinase (PDK1) plays a pivotal role. Identification and characterization of a PDK1 inhibitor is of paramount importance. Further, for efficacious treatment of colorectal cancers, combinatorial regimens are essential. To this end, we opted to identify a PDK1 inhibitor using computational structure-based drug design FINDSITEcomb and perform combinatorial studies with 5-FU for efficacious treatment of colorectal cancers. Methods: Using computational structure-based drug design FINDSITEcomb, stearic acid (SA) was identified as a possible PDK1 inhibitor. Elucidation of the mechanism of action of SA was performed using flow cytometry, clonogenic assays. Results: When the growth inhibitory potential of SA was tested on colorectal adenocarcinoma (DLD-1) cells, a 50% inhibitory concentration (IC50) of 60 µM was recorded. Moreover, SA inhibited the proliferation potential of DLD-1 cells as shown by the clonogenic assay and there was a sustained response even after withdrawal of the compound. Elucidation of the mechanism of action revealed, that the inhibitory effect of SA was through the programmed cell death pathway. There was increase in the number of apoptotic and multicaspase positive cells. SA also impacted the levels of the cell survival protein Bcl-2. With the aim of achieving improved treatment for colorectal cancer, we opted to combine 5-fluorouracil (5-FU), the currently used drug in the clinic, with SA. Combining SA with 5-FU, revealed a synergistic effect in which the IC50 of 5-FU decreased from 25 to 6 µM upon combination with 60 µM SA. Further, SA did not inhibit non-tumorigenic NIH-3T3 proliferation. Conclusions: We envision that this significant decrease in the IC50 of 5-FU could translate into less side effects of 5-FU and increase the efficacy of the treatment due to the multifaceted action of SA. The data generated from the current studies on the inhibition of colorectal adenocarcinoma by SA discovered by the use of the computational program as well as synergistic action with 5-FU should open up novel therapeutic options for the management of colorectal adenocarcinomas.

scholarly journals Crystal structures of human ENPP1 in apo and bound forms

2020 ◽  
Vol 76 (9) ◽  
pp. 889-898 ◽  
Author(s):  
Matthew L. Dennis ◽  
Janet Newman ◽  
Olan Dolezal ◽  
Meghan Hattarki ◽  
Regina N. Surjadi ◽  
...  
Keyword(s):  
Immune System ◽  
Drug Design ◽  
Crystal Structures ◽  
Cyclic Gmp ◽  
Therapeutic Target ◽  
Structure Based Drug Design ◽  
X Ray ◽  
Crystallization System ◽  
Causes Of Mortality ◽  
Cancerous Cells

Cancer is one of the leading causes of mortality in humans, and recent work has focused on the area of immuno-oncology, in which the immune system is used to specifically target cancerous cells. Ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) is an emerging therapeutic target in human cancers owing to its role in degrading cyclic GMP-AMP (cGAMP), an agonist of the stimulator of interferon genes (STING). The available structures of ENPP1 are of the mouse enzyme, and no structures are available with anything other than native nucleotides. Here, the first X-ray crystal structures of the human ENPP1 enzyme in an apo form, with bound nucleotides and with two known inhibitors are presented. The availability of these structures and a robust crystallization system will allow the development of structure-based drug-design campaigns against this attractive cancer therapeutic target.

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