Computational Strategy Revealing the Structural Determinant of Ligand Selectivity towards Highly Similar Protein Targets

2019 ◽  
Vol 21 (1) ◽  
pp. 76-88
Author(s):  
Hanxun Wang ◽  
Yinli Gao ◽  
Jian Wang ◽  
Maosheng Cheng

Background: Poor selectivity of drug candidates may lead to toxicity and side effects accounting for as high as 60% failure rate, thus, the selectivity is consistently significant and challenging for drug discovery. Objective: To find highly specific small molecules towards very similar protein targets, multiple strategies are always employed, including (1) To make use of the diverse shape of binding pocket to avoid steric bump; (2) To increase binding affinities for favorite residues; (3) To achieve selectivity through allosteric regulation of target; (4) To stabalize the inactive conformation of protein target and (5) To occupy dual binding pockets of single target. Conclusion: In this review, we summarize computational strategies along with examples of their successful applications in designing selective ligands, with the aim to provide insights into everdiversifying drug development practice and inspire medicinal chemists to utilize computational strategies to avoid potential side effects due to low selectivity of ligands.

2019 ◽  
Vol 20 (6) ◽  
pp. 1444 ◽  
Author(s):  
Soria Iatmanen-Harbi ◽  
lucile Senicourt ◽  
Vassilios Papadopoulos ◽  
Olivier Lequin ◽  
Jean-Jacques Lacapere

The optimization of translocator protein (TSPO) ligands for Positron Emission Tomography as well as for the modulation of neurosteroids is a critical necessity for the development of TSPO-based diagnostics and therapeutics of neuropsychiatrics and neurodegenerative disorders. Structural hints on the interaction site and ligand binding mechanism are essential for the development of efficient TSPO ligands. Recently published atomic structures of recombinant mammalian and bacterial TSPO1, bound with either the high-affinity drug ligand PK 11195 or protoporphyrin IX, have revealed the membrane protein topology and the ligand binding pocket. The ligand is surrounded by amino acids from the five transmembrane helices as well as the cytosolic loops. However, the precise mechanism of ligand binding remains unknown. Previous biochemical studies had suggested that ligand selectivity and binding was governed by these loops. We performed site-directed mutagenesis to further test this hypothesis and measured the binding affinities. We show that aromatic residues (Y34 and F100) from the cytosolic loops contribute to PK 11195 access to its binding site. Limited proteolytic digestion, circular dichroism and solution two-dimensional (2-D) NMR using selective amino acid labelling provide information on the intramolecular flexibility and conformational changes in the TSPO structure upon PK 11195 binding. We also discuss the differences in the PK 11195 binding affinities and the primary structure between TSPO (TSPO1) and its paralogous gene product TSPO2.


Marine Drugs ◽  
2019 ◽  
Vol 17 (6) ◽  
pp. 377 ◽  
Author(s):  
Su Hui Seong ◽  
Pradeep Paudel ◽  
Jeong-Wook Choi ◽  
Dong Hyun Ahn ◽  
Taek-Jeong Nam ◽  
...  

Modulation of multiple protein targets with a single compound is essential for the effective treatment of central nervous system disorders. In our previous G protein-coupled receptor (GPCR) cell-based study, a selective human monoamine oxidase (hMAO)-A inhibitor, eckol, stimulated activity of dopamine D3 and D4 receptors. This result led to our interest in marine phlorotannin-mediated modulation of hMAO enzymes and related GPCRs in neuronal disorders. Here, we evaluate the multi-target effects of phloroglucinol, phlorofucofuroeckol-A (PFF-A), and dieckol by screening their modulatory activity against hMAO-A and -B and various neuronal GPCRs. Among the tested phlorotannins, PFF-A showed the strongest inhibitory activity against both hMAO isoforms, with higher selectivity toward hMAO-B than hMAO-A. Enzyme kinetics and docking data revealed that PFF-A noncompetitively acts on hMAOs into the alternative binding pocket of enzymes with allosteric functions. In a functional assay for GPCR screening, dieckol and PFF-A exhibited a multi-target combination of D3R/D4R agonism and D1/5HT1A/NK1 antagonism. In particular, they effectively stimulated D3R and D4R, compared to other GPCRs. Docking analysis confirmed that dieckol and PFF-A successfully docked into the conserved active sites of D3R and D4R and interacted with aspartyl and serine residues in the orthosteric binding pockets of the respective receptors. Based on our experimental and computational data, we established the structure-activity relationship between tested phlorotannins and target proteins, including hMAOs and GPCRs. Our current findings suggest that hMAO inhibitors dieckol and PFF-A, major phlorotannins of edible brown algae with multi-action on GPCRs, are potential agents for treatment of psychological disorders and Parkinson’s disease.


Pharmaceutics ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 315
Author(s):  
Katarina Kores ◽  
Janez Konc ◽  
Urban Bren

Thiazolidinediones form drugs that treat insulin resistance in type 2 diabetes mellitus. Troglitazone represents the first drug from this family, which was removed from use by the FDA due to its hepatotoxicity. As an alternative, rosiglitazone was developed, but it was under the careful watch of FDA for a long time due to suspicion, that it causes cardiovascular diseases, such as heart failure and stroke. We applied a novel inverse molecular docking protocol to discern the potential protein targets of both drugs. Troglitazone and rosiglitazone were docked into predicted binding sites of >67,000 protein structures from the Protein Data Bank and examined. Several new potential protein targets with successfully docked troglitazone and rosiglitazone were identified. The focus was devoted to human proteins so that existing or new potential side effects could be explained or proposed. Certain targets of troglitazone such as 3-oxo-5-beta-steroid 4-dehydrogenase, neutrophil collagenase, stromelysin-1, and VLCAD were pinpointed, which could explain its hepatoxicity, with additional ones indicating that its application could lead to the treatment/development of cancer. Results for rosiglitazone discerned its interaction with members of the matrix metalloproteinase family, which could lead to cancer and neurodegenerative disorders. The concerning cardiovascular side effects of rosiglitazone could also be explained. We firmly believe that our results deepen the mechanistic understanding of the side effects of both drugs, and potentially with further development and research maybe even help to minimize them. On the other hand, the novel inverse molecular docking protocol on the other hand carries the potential to develop into a standard tool to predict possible cross-interactions of drug candidates potentially leading to adverse side effects.


2018 ◽  
Vol 25 (21) ◽  
pp. 2503-2519 ◽  
Author(s):  
Anne Kokel ◽  
Marianna Torok

Background: Since the first isolation of antimicrobial peptides (AMPs) they have attracted extensive interest in medicinal chemistry. However, only a few AMP-based drugs are currently available on the market. Despite their effectiveness, biodegradability, and versatile mode of action that is less likely to induce resistance compared to conventional antibiotics, AMPs suffer from major issues that need to be addressed to broaden their use. Notably, AMPs can lack selectivity leading to side effects and cytotoxicity, and also exhibit in vivo instability. Several strategies are being actively considered to overcome the limitations that restrain the success of AMPs. Methods: In the current work, recent strategies reported for improving AMPs in the context of drug design and delivery were surveyed, and also their possible impact on patients and the environment was assessed. Results: As a major advantage AMPs possess an easily tunable skeleton offering opportunities to improve their properties. Strategic structural modifications and the beneficial properties of cyclic or branched AMPs in term of stability have been reported. The conjugation of AMPs with nanoparticles has also been explored to increase their in vivo stability. Other techniques such as the coupling of AMPs with specific antibodies aim to increase the selectivity of the potential drug towards the target. These strategies were evaluated for their effect on the environment highlighting green technologies. Conclusion: Although further research is needed taking into account both environmental and human health consequences of novel AMPs, several of these compounds are promising drug candidates for use in sustainable medicine.


2020 ◽  
Vol 27 (28) ◽  
pp. 4720-4740 ◽  
Author(s):  
Ting Yang ◽  
Xin Sui ◽  
Bing Yu ◽  
Youqing Shen ◽  
Hailin Cong

Multi-target drugs have gained considerable attention in the last decade owing to their advantages in the treatment of complex diseases and health conditions linked to drug resistance. Single-target drugs, although highly selective, may not necessarily have better efficacy or fewer side effects. Therefore, more attention is being paid to developing drugs that work on multiple targets at the same time, but developing such drugs is a huge challenge for medicinal chemists. Each target must have sufficient activity and have sufficiently characterized pharmacokinetic parameters. Multi-target drugs, which have long been known and effectively used in clinical practice, are briefly discussed in the present article. In addition, in this review, we will discuss the possible applications of multi-target ligands to guide the repositioning of prospective drugs.


Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1151
Author(s):  
Chenyun Guo ◽  
Zhihua Wu ◽  
Weiliang Lin ◽  
Hao Xu ◽  
Ting Chang ◽  
...  

Suramin was initially used to treat African sleeping sickness and has been clinically tested to treat human cancers and HIV infection in the recent years. However, the therapeutic index is low with numerous clinical side-effects, attributed to its diverse interactions with multiple biological macromolecules. Here, we report a novel binding target of suramin, human Raf1 kinase inhibitory protein (hRKIP), which is an important regulatory protein involved in the Ras/Raf1/MEK/ERK (MAPK) signal pathway. Biolayer interference technology showed that suramin had an intermediate affinity for binding hRKIP with a dissociation constant of 23.8 µM. Both nuclear magnetic resonance technology and molecular docking analysis revealed that suramin bound to the conserved ligand-binding pocket of hRKIP, and that residues K113, W173, and Y181 play crucial roles in hRKIP binding suramin. Furthermore, suramin treatment at 160 µM could profoundly increase the ERK phosphorylation level by around 3 times. Our results indicate that suramin binds to hRKIP and prevents hRKIP from binding with hRaf1, thus promoting the MAPK pathway. This work is beneficial to both mechanistically understanding the side-effects of suramin and efficiently improving the clinical applications of suramin.


Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3269 ◽  
Author(s):  
Lucas Defelipe ◽  
Juan Arcon ◽  
Carlos Modenutti ◽  
Marcelo Marti ◽  
Adrián Turjanski ◽  
...  

Simulations of molecular dynamics (MD) are playing an increasingly important role in structure-based drug discovery (SBDD). Here we review the use of MD for proteins in aqueous solvation, organic/aqueous mixed solvents (MDmix) and with small ligands, to the classic SBDD problems: Binding mode and binding free energy predictions. The simulation of proteins in their condensed state reveals solvent structures and preferential interaction sites (hot spots) on the protein surface. The information provided by water and its cosolvents can be used very effectively to understand protein ligand recognition and to improve the predictive capability of well-established methods such as molecular docking. The application of MD simulations to the study of the association of proteins with drug-like compounds is currently only possible for specific cases, as it remains computationally very expensive and labor intensive. MDmix simulations on the other hand, can be used systematically to address some of the common tasks in SBDD. With the advent of new tools and faster computers we expect to see an increase in the application of mixed solvent MD simulations to a plethora of protein targets to identify new drug candidates.


2020 ◽  
Author(s):  
Rafael Blasco ◽  
Julio Coll

<p>The non-structural protein 7 (nsp7) of Severe Acute Respiratory Syndrome (SARS) coronaviruses was selected as a new target to potentially interfere with viral replication. The nsp7s are one of the most conserved, unique and small coronavirus proteins having a critical, yet intriguing participation on the replication of the long viral RNA genome after complexing with nsp8 and nsp12. Despite the difficulties of having no previous binding pocket, two high-throughput virtual blind screening of 158240 natural compounds > 400 Da by AutoDock Vina against nsp7.1ysy identified 655 leads displaying predicted binding affinities between 10 to 1100 nM. The leads were then screened against 14 available conformations of nsp7 by both AutoDock Vina and seeSAR programs employing different binding score algorithms, to identify 20 consensus top-leads. Further <i>in silico</i> predictive analysis of physiological and toxicity ADMET criteria (chemical properties, adsorption, metabolism, toxicity) narrowed top-leads to a few drug-like ligands many of them showing steroid-like structures. A final optimization by search for structural similarity to the top drug-like ligand that were also commercially available, yielded a collection of predicted novel ligands with ~100-fold higher-affinity whose antiviral activity may be experimentally validated. Additionally, these novel nsp7-interacting ligands and/or their further optimized derivatives, may offer new tools to investigate the intriguing role of nsp7 on replication of coronaviruses.</p>


2021 ◽  
Author(s):  
Mohd. Suhail

<p><a>It has been a great challenge for scientists to develop an anti-covid drug/vaccine with fewer side effects, since the coronavirus began. Of course, the prescription of chiral drugs (chloroquine or hydroxychloroquine) has been proved wrong because these chiral drugs neither kill the virus nor eliminate it from the body, but block SARS-CoV-2 from binding to human cells. Another hurdle in front of the world, is not only the positive test of the patient recovered from coronavirus but also the second wave of Covid 19. Hence, the word demands such a drug or drug combination which not only prevents the entry of SARS-CoV-2 in the human cell but also eliminates it or its material from the body completely. The presented computational study explains (i) why the prescription of chiral drugs was not satisfactory (ii) what types of modification can make their prescription satisfactory (iii) the mechanism of action of chiral drugs (chloroquine and hydroxychloroquine) to block SARS-CoV-2 from binding to human cells, and (iv) the strength of mefloquine to eliminate SARS-CoV-2. As the main protease (M<b><sup>pro</sup></b>) of microbes is considered as an effective target for drug design and development, the binding affinities of mefloquine with the main proteases (M<sup>pros</sup>) of JC virus and SARS-CoV-2, were calculated, and then compared to know the eliminating strength of mefloquine against SARS-CoV-2. The main protease (M<sup>pro</sup>) of JC virus was taken because mefloquine has already shown a tremendous result of eliminating it from the body. The current study includes the docking results and literature data in support of the prescription of a combination of S-(+)-hydroxychloroquine and (+) mefloquine. Besides, the presented study also confirms that the prescription of only hydroxychloroquine would not be so effective as in combined form with mefloquine.</a></p>


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