scholarly journals Interactions of Sea Anemone Toxins with Insect Sodium Channel—Insights from Electrophysiology and Molecular Docking Studies

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1302
Author(s):  
Beata Niklas ◽  
Milena Jankowska ◽  
Dalia Gordon ◽  
László Béress ◽  
Maria Stankiewicz ◽  
...  

Animal venoms are considered as a promising source of new drugs. Sea anemones release polypeptides that affect electrical activity of neurons of their prey. Voltage dependent sodium (Nav) channels are the common targets of Av1, Av2, and Av3 toxins from Anemonia viridis and CgNa from Condylactis gigantea. The toxins bind to the extracellular side of a channel and slow its fast inactivation, but molecular details of the binding modes are not known. Electrophysiological measurements on Periplaneta americana neuronal preparation revealed differences in potency of these toxins to increase nerve activity. Av1 and CgNa exhibit the strongest effects, while Av2 the weakest effect. Extensive molecular docking using a modern SMINA computer method revealed only partial overlap among the sets of toxins’ and channel’s amino acid residues responsible for the selectivity and binding modes. Docking positions support earlier supposition that the higher neuronal activity observed in electrophysiology should be attributed to hampering the fast inactivation gate by interactions of an anemone toxin with the voltage driven S4 helix from domain IV of cockroach Nav channel (NavPaS). Our modelling provides new data linking activity of toxins with their mode of binding in site 3 of NavPaS channel.

Author(s):  
Suman Rohilla ◽  
Ranju Bansal ◽  
Puneet Chauhan ◽  
Sonja Kachler ◽  
Karl-Norbert Klotz

Background: Adenosine receptors (AR) have emerged as competent and innovative nondopaminergic targets for the development of potential drug candidates and thus constitute an effective and safer treatment approach for Parkinson’s disease (PD). Xanthine derivatives are considered as potential candidates for the treatment Parkinson’s disease due to their potent A2A AR antagonistic properties. Objective: The objectives of the work are to study the impact of substituting N7-position of 8-m/pchloropropoxyphenylxanthine structure on in vitro binding affinity of compounds with various AR subtypes, in vivo antiparkinsonian activity and binding modes of newly synthesized xanthines with A2A AR in molecular docking studies. Methods: Several new 7-substituted 8-m/p-chloropropoxyphenylxanthine analogues have been prepared. Adenosine receptor binding assays were performed to study the binding interactions with various subtypes and perphenazine induced rat catatonia model was used for antiparkinsonian activity. Molecular docking studies were performed using Schrödinger molecular modeling interface. Results: 8-para-substituted xanthine 9b bearing an N7-propyl substituent displayed the highest affinity towards A2A AR (Ki = 0.75 µM) with moderate selectivity versus other AR subtypes. 7-Propargyl analogue 9d produced significantly longlasting antiparkinsonian effects and also produced potent and selective binding affinity towards A2A AR. In silico docking studies further highlighted the crucial structural components required to develop xanthine derived potential A2A AR ligands as antiparkinsonian agents. Conclusion: A new series of 7-substituted 8-m/p-chloropropoxyphenylxanthines having good affinity for A2A AR and potent antiparkinsonian activity has been developed.


2021 ◽  
Vol 14 (7) ◽  
pp. 685
Author(s):  
Sandra Amanda Kozieł ◽  
Monika Katarzyna Lesiów ◽  
Daria Wojtala ◽  
Edyta Dyguda-Kazimierowicz ◽  
Dariusz Bieńko ◽  
...  

A group of cytotoxic half-sandwich iridium(III) complexes with aminomethyl(diphenyl)phosphine derived from fluoroquinolone antibiotics exhibit the ability to (i) accumulate in the nucleus, (ii) induce apoptosis, (iii) activate caspase-3/7 activity, (iv) induce the changes in cell cycle leading to G2/M phase arrest, and (v) radicals generation. Herein, to elucidate the cytotoxic effects, we investigated the interaction of these complexes with DNA and serum proteins by gel electrophoresis, fluorescence spectroscopy, circular dichroism, and molecular docking studies. DNA binding experiments established that the complexes interact with DNA by moderate intercalation and predominance of minor groove binding without the capability to cause a double-strand cleavage. The molecular docking study confirmed two binding modes: minor groove binding and threading intercalation with the fluoroquinolone part of the molecule involved in pi stacking interactions and the Ir(III)-containing region positioned within the major or minor groove. Fluorescence spectroscopic data (HSA and apo-Tf titration), together with molecular docking, provided evidence that Ir(III) complexes can bind to the proteins in order to be transferred. All the compounds considered herein were found to bind to the tryptophan residues of HSA within site I (subdomain II A). Furthermore, Ir(III) complexes were found to dock within the apo-Tf binding site, including nearby tyrosine residues.


2018 ◽  
Vol 7 (12) ◽  
pp. 551 ◽  
Author(s):  
Shailima Rampogu ◽  
Doneti Ravinder ◽  
Smita Pawar ◽  
Keun Lee

Cervical cancer is regarded as one of the major burdens noticed in women next to breast cancer. Although, human papilloma viruses (HPVs) are regarded as the principal causative agents, they require certain other factors such as oestrogen hormone to induce cervical cancer. Aromatase is an enzyme that converts androgens into oestrogens and hindering this enzyme could subsequently hamper the formation of oestrogen thereby alleviating the disease. Accordingly, in the current investigation, a structure based pharmacophore was generated considering two proteins bearing the Protein Data Bank (PDB) codes 3EQM (pharm 1) and 3S7S (pharm 2), respectively. The two models were employed as the 3D query to screen the in-house built natural compounds database. The obtained 51 compounds were escalated to molecular docking studies to decipher on the binding affinities and to predict the quintessential binding modes which were affirmed by molecular dynamics (MD) simulations. The compound has induced dose-dependent down regulation of PP2B, Nitric oxide synthase-2 (NOS2), and Interleukin 6 (IL-6) genes in the HeLa cells and has modulated the expression of apoptotic genes such as Bax, Bcl2, and caspases-3 at different concentrations. These results guide us to comprehend that the identified aromatase inhibitor was effective against the cervical cancer cells and additionally could server as scaffolds in designing new drugs.


Author(s):  
Sanchaita Rajkhowa ◽  
Ramesh C. Deka

Molecular docking is a key tool in structural biology and computer-assisted drug design. Molecular docking is a method which predicts the preferred orientation of a ligand when bound in an active site to form a stable complex. It is the most common method used as a structure-based drug design. Here, the authors intend to discuss the various types of docking methods and their development and applications in modern drug discovery. The important basic theories such as sampling algorithm and scoring functions have been discussed briefly. The performances of the different available docking software have also been discussed. This chapter also includes some application examples of docking studies in modern drug discovery such as targeted drug delivery using carbon nanotubes, docking of nucleic acids to find the binding modes and a comparative study between high-throughput screening and structure-based virtual screening.


Molecules ◽  
2020 ◽  
Vol 25 (8) ◽  
pp. 1789 ◽  
Author(s):  
Julia Krzywik ◽  
Witold Mozga ◽  
Maral Aminpour ◽  
Jan Janczak ◽  
Ewa Maj ◽  
...  

Colchicine is a well-known compound with strong antiproliferative activity that has had limited use in chemotherapy because of its toxicity. In order to create more potent anticancer agents, a series of novel colchicine derivatives have been obtained by simultaneous modification at C7 (amides and sulfonamides) and at C10 (methylamino group) positions and characterized by spectroscopic methods. All the synthesized compounds have been tested in vitro to evaluate their cytotoxicity toward A549, MCF-7, LoVo, LoVo/DX and BALB/3T3 cell lines. Additionally, the activity of the studied compounds was investigated using computational methods involving molecular docking of the colchicine derivatives to β-tubulin. The majority of the obtained derivatives exhibited higher cytotoxicity than colchicine, doxorubicin or cisplatin against tested cancer cell lines. Furthermore, molecular modeling studies of the obtained compounds revealed their possible binding modes into the colchicine binding site of tubulin.


2021 ◽  
Vol 59 (4) ◽  
pp. 441
Author(s):  
Hoàng Thị Kim Dung ◽  
Hoang-Phuc Nguyen ◽  
Thi-Kim-Chi Huynh

Discovering and developing drugs to treat Alzheimer's disease (AD) have been a crucial target for many decades. According to a large number of later studies, acetylcholinesterase (AChE) plays an important role in AD treatment. On the other hand, flavonoids are natural compounds that possessed a wide variety of bioactivities, including the inhibitory activity on AChE. In this study, we reported the structure and activity relationship of flavone and flavanone derivatives that semi-synthesized and synthesized from flower buds of Styphnolobium japonicum (Leguminosae) and citrus peels against AChE. The results showed that the introducing of the new functional groups that leads to increasing 3-folds better AChE inhibition of compound Q2 and Q4 than that of the original. The molecular docking study was investigated in order to illuminate the experimental results and find their binding modes.


2020 ◽  
Vol 71 (5) ◽  
pp. 163-181
Author(s):  
Madalina Marina Hrubaru ◽  
Carmellina Daniela Badiceanu ◽  
Anthony Chinonso Ekennia ◽  
Sunday N. Okafor ◽  
Cristian Enache ◽  
...  

Alzheimer�s is a progresive neurodegenerative disease that interferes with human cognitive ability, memory and behavior. The inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes are major therapeutic routes for the treatment of Alzheimer disease. In the study, nevel bis-polymethylenquinoline-bis-carboxamides (3a-f) and bis-polymethylenquinoline-bis-carboxylic acids (5a-b) having as precursor benzidine, were obtained in good yields by Pfitzinger condensation reactions of bis-isatines with corresponding cyclanones. The compounds were characterized by elemental analysis, FT-IR, NMR and mass spectrometry. Furthermore, the compounds were subjected to molecular docking dynamics simulations to ascertain their potentials as inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Molecular docking simulations showed varied binding activities towards the two binding sites of acetylcholinesterase: 4EY7 and 1OCD, and human butyrylcholinesterase: 1P0I. Compounds 3e and 5b demostrated strong binding affinities with 1P0I, 1OCD and 4EY7 biotargets similar to the binding modes of donepezil and tacrine (co-crystallized inhibitors of acetylcholinesterase) and butyrate (co-crystallized inhibitors of butyrylcholinesterase).


2020 ◽  
Vol 20 (9) ◽  
pp. 788-800 ◽  
Author(s):  
Sobhi M. Gomha ◽  
Zeinab A. Muhammad ◽  
Elham Ezz El-Arab ◽  
Amira M. Elmetwally ◽  
Abdelaziz A. El-Sayed ◽  
...  

Objective: The reaction of bis(4-amino-4H-1,2,4-triazole-3-thiol) with hydrazonoyl halides and α-halo-ketones gave a new series of bis-1,2,4-triazolo[3,4-b]thiadiazine derivatives. Methods: The structure of the new products was established on the basis of their elemental and spectral data (mass, 1H NMR, 13C NMR and IR) and an alternate method. Results: Several of the synthesized products were subjected to in vitro anticancer screening against human hepatocellular carcinoma (HepG-2) and the results showed that compounds 16, 14 and 12 have promising activities (IC50 value of 24.8±9.1, 28.3±0.5, and 31±2.9μM, respectively) compared with Harmine reference drug (IC50 value of 22.4±1.11 μM). Conclusion: Moreover, molecular docking studies were performed to analyze the binding modes of the discovered hits into the active site of DYRK1A using iGEMDOCK.


2020 ◽  
Vol 12 (1) ◽  
pp. 83-87
Author(s):  
Rolly Yadav ◽  
Anwesh Pandey ◽  
Nidhi Awasthi ◽  
Anamika Shukla

The combination of experimental and computational strategies has been of great value in the identification and development of metabolism of drugs. Nowadays modern drug design, molecular docking methods are helpful in exploring the ligand conformations adopted within the binding sites of macro-molecular targets such as DNA, proteins, and enzymes, there by reducing cost, time and wayward efforts of chemist. Since the development of the algorithms in the 1980s, molecular docking became an important tool in drug discovery like investigation of crucial molecular events, including ligand binding modes and the corresponding intermolecular interactions that stabilize the ligand-receptor complex, can be conveniently performed. In present study we have tried to investigate the drug binding pocket of various cytochrome (CYP) enzymes found in humans. All structures of drugs are optimized at B3LYP/6-31** level of theory using Gaussian program suite. Docking of substrate-enzyme duo was done using AUTODOCK 4.0. Computational docking revealed that almost all drugs have same binding pocket with varied binding affinities due to change in interactions and interacting distance from heme prosthetic moiety with transition metal iron as chelating ion.


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