scholarly journals Revealing the selective mechanisms of inhibitors to PARP-1 and PARP-2 via multiple computational methods

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9241
Author(s):  
Hongye Hu ◽  
Buran Chen ◽  
Danni Zheng ◽  
Guanli Huang

Background Research has shown that Poly-ADP-ribose polymerases 1 (PARP-1) is a potential therapeutic target in the clinical treatment of breast cancer. An increasing number of studies have focused on the development of highly selective inhibitors that target PARP-1 over PARP-2, its closest isoform, to mitigate potential side effects. However, due to the highly conserved and similar binding sites of PARP-1 and PARP-2, there is a huge challenge for the discovery and design of PARP-1 inhibitors. Recently, it was reported that a potent PARP-1 inhibitor named NMS-P118 exhibited greater selectivity to PARP-1 over PARP-2 compared with a previously reported drug (Niraparib). However, the mechanisms underlying the effect of this inhibitor remains unclear. Methods In the present study, classical molecular dynamics (MD) simulations and accelerated molecular dynamics (aMD) simulations combined with structural and energetic analysis were used to investigate the structural dynamics and selective mechanisms of PARP-1 and PARP-2 that are bound to NMS-P118 and Niraparib with distinct selectivity. Results The results from classical MD simulations indicated that the selectivity of inhibitors may be controlled by electrostatic interactions, which were mainly due to the residues of Gln-322, Ser-328, Glu-335, and Tyr-455 in helix αF. The energetic differences were corroborated by the results from aMD simulations. Conclusion This study provides new insights about how inhibitors specifically bind to PARP-1 over PARP-2, which may help facilitate the design of highly selective PARP-1 inhibitors in the future.

Processes ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 1749
Author(s):  
Yuqi Zhang ◽  
Li Chen ◽  
Xiaoyu Wang ◽  
Yanyan Zhu ◽  
Yongsheng Liu ◽  
...  

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is a type of Ribonucleic Acid (RNA) coronavirus and it has infected and killed many people around the world. It is reported that the receptor binding domain of the spike protein (S_RBD) of the SARS-CoV-2 virus is responsible for attachment to human angiotensin converting enzyme II (ACE2). Many researchers are attempting to search potential inhibitors for fighting SARS-CoV-2 infection using theoretical or experimental methods. In terms of experimental and theoretical research, Cefuroxime, Erythromycin, Lincomycin and Ofloxacin are the potential inhibitors of SARS-CoV-2. However, the interactive mechanism of the protein SARS-CoV-2 and the inhibitors are still elusive. Here, we investigated the interactions between S_RBD and the inhibitors using molecular dynamics (MD) simulations. Interestingly, we found that there are two binding sites of S_RBD for the four small molecules. In addition, our analysis also illustrated that hydrophobic and π-π stacking interactions play crucial roles in the interactions between S_RBD and the small molecules. In our work, we also found that small molecules with glycosyl group have more effect on the conformation of S_RBD than other inhibitors, and they are also potential inhibitors for the genetic variants of SARS-CoV-2. This study provides in silico-derived mechanistic insights into the interactions of S_RBD and inhibitors, which may provide new clues for fighting SARS-CoV-2 infection.


2019 ◽  
Author(s):  
Qiang Shao ◽  
Jinan Wang ◽  
Weiliang Zhu

AbstractIn this work, the combined influence of urea and KI on protein native structure is quantitatively investigated through the comparative molecular dynamics simulations on the structural dynamics of a polypeptide of TRPZIP4 in a series of urea/KI mixed solutions (urea concentration: 4M, KI salt concentration: 0M-6M). The observed enhanced denaturing ability of urea/KI mixture can be explained by direct interactions of urea/K+/water towards protein (electrostatic and vdW interactions from urea and electrostatic interactions from K+ and water) and indirect influence of KI on the strengthened interaction of urea towards protein backbone and side-chain. The latter indirect influence is fulfilled through the weakening of hydrogen bonding network among urea and water by the appearance of K+–water and I—urea interactions. As a result, the denaturing ability enhancement of urea and KI mixed solution is induced by the collaborative behavior of urea and KI salt.


2020 ◽  
Author(s):  
Shahin Sowlati-Hashjin ◽  
Paola Carbone ◽  
Mikko Karttunen

AbstractPolyhexamethylene biguanide (PHMB) is a cationic polymer with antimicrobial and antiviral properties. It has been commonly accepted that the antimicrobial activity is due the ability of PHMB to perforate the bacterial phospholipid membrane leading ultimately to its death. In this study we show by the means of atomistic molecular dynamics (MD) simulations that while the PHMB molecules attach to the surface of the phospholipid bilayer and partially penetrate it, they do not cause any pore formation at least within the microsecond simulation times. The polymers initially adsorb onto the membrane surface via the favourable electrostatic interactions between the phospholipid headgroups and the biguanide groups, and then partially penetrate the membrane slightly disrupting its structure. This, however, does not lead to the formation of any pores. The microsecond-scale simulations reveal that it is unlikely for PHMB to spontaneously pass through the phospholipid membrane. Our findings suggest that PHMB translocation across the bilayer may take place through binding to the phospholipids. Once inside the cell, the polymer can effectively ‘bind’ to DNA through extensive interactions with DNA phosphate backbone, which can potentially block the DNA replication process or activate DNA repair pathways.TOC Graphic


2021 ◽  
Author(s):  
kalyan immadisetty ◽  
Peter Kekenes-Huskey

The ATP activated P2X4 receptor plays a prominent role in pain perception and modulation and thus may constitute an alternative therapeutic target for controlling pain. Given the biomedical relevance of P2X4 receptors, and poor understanding of molecular mechanisms that describe its gating by ATP, a fundamental understanding of the functional mechanism of these channels is warranted. Through classical all-atom molecular dynamics (MD) simulations we investigated the number of ATP molecules required to open (activate) the receptor for it to conduct ions. Since crystal structures of human P2X4 are not yet available, the crystal structures of highly-homologous zebrafish P2X4 (zfP2X4) structures were utilized for this study. It has been identified that at least two ATP molecules are required to prevent the open state receptor from collapsing back to a closed state. Additionally, we have discovered two metal binding sites, one at the intersection of the three monomers in the ectodomain (MBS1) and the second one near the ATP binding site (MBS2), both of which are occupied by the potassium ions. This observation draws its comparison to the gulf coast P2X receptor that it possesses the same two metal binding sites, however, MBS1 and MBS2 in this receptor are occupied by zinc and magnesium, respectively.


Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2917-2917
Author(s):  
Tai-Sung Lee ◽  
Steven Potts ◽  
Hagop Kantarjian ◽  
Jorge Cortes ◽  
Francis Giles ◽  
...  

Abstract Molecular dynamics (MD) simulations on the complex of imatinib with the wild-type, T315I, and other 10 P-loop mutants of the tyrosine kinase Bcr-Abl have been performed to study the imatinib resistance mechanism at the atomic level. MD simulations show that large scale computational simulations could offer insight information that a static structure or simple homology modeling methods cannot provide for studying the Bcr-Abl imatinib resistance problem, especially in the case of conformational changes due to remote mutations. By utilizing the Molecular Mechanics/Poisson-Boltzmann surface area (MM-PBSA) techniques and analyzing the interactions between imatinib and individual residues, imatinib resistance mechanisms not previously thought have been revealed. Non-directly contacted P-loop mutations either unfavorably change the direct electrostatic interactions with imatinib, or cause the conformational changes influencing the contact energies between imatinib and other non-P-loop residues. We demonstrate that imatinib resistance of T315I mainly comes from the breakdown of the interactions between imatinib and E286 and M290, contradictory to previously suggested that the missing hydrogen bonding is the main contribution. We also demonstrate that except for the mutations of the direct contact residues, such as L248 and Y253, the unfavorable electrostatic interaction between P-loop and imatinib is the main reason for resistance for the P-loop mutations. Furthermore, in Y255H, protonation of the histidin is essential for rendering this mutation resistant to Gleevec. Our results demonstrate that MD is a powerful way to verify and predict clinical response or resistance to imatinib and other potential drugs.


2015 ◽  
Vol 48 (4) ◽  
pp. 479-487 ◽  
Author(s):  
Kalli Kappel ◽  
Yinglong Miao ◽  
J. Andrew McCammon

AbstractElucidating the detailed process of ligand binding to a receptor is pharmaceutically important for identifying druggable binding sites. With the ability to provide atomistic detail, computational methods are well poised to study these processes. Here, accelerated molecular dynamics (aMD) is proposed to simulate processes of ligand binding to a G-protein-coupled receptor (GPCR), in this case the M3 muscarinic receptor, which is a target for treating many human diseases, including cancer, diabetes and obesity. Long-timescale aMD simulations were performed to observe the binding of three chemically diverse ligand molecules: antagonist tiotropium (TTP), partial agonist arecoline (ARc) and full agonist acetylcholine (ACh). In comparison with earlier microsecond-timescale conventional MD simulations, aMD greatly accelerated the binding of ACh to the receptor orthosteric ligand-binding site and the binding of TTP to an extracellular vestibule. Further aMD simulations also captured binding of ARc to the receptor orthosteric site. Additionally, all three ligands were observed to bind in the extracellular vestibule during their binding pathways, suggesting that it is a metastable binding site. This study demonstrates the applicability of aMD to protein–ligand binding, especially the drug recognition of GPCRs.


2017 ◽  
Author(s):  
Yeping Sun ◽  
Po Tian

ABSTRACTA conventional picture for major histocompatibility complex class I (MHCI) antigen presentation is that the terminal anchor residues of the antigenic peptide bind to the pockets at the bottom of the MHC cleft, leaving the central peptide residues exposed for T cell antigen receptor (TCR) recognition. However, in the present study, we show that in canonical or accelerated molecular dynamics (MD) simulations, the peptide terminus in some immunodominant peptide-MHCI (pMHCI) complexes can detach from their binding pockets and stretch outside the MHC cleft. These pMHCI complexes include the complex of the H-2Kb and the lymphocytic choriomeningitis virus (LCMV) gp33 peptide, and the complex of the HLA-A*0201 and the influenza A virus M1 peptide. The detached peptide terminus becomes the most prominent spot at the pMHC interface, and so can serves as a novel TCR recognition target. Thus, peptide terminus detaching may be a novel mechanism for MHC antigen presentation.


2021 ◽  
Vol 8 ◽  
Author(s):  
Shraddha Parate ◽  
Shailima Rampogu ◽  
Gihwan Lee ◽  
Jong Chan Hong ◽  
Keun Woo Lee

Protein-protein interactions are indispensable physiological processes regulating several biological functions. Despite the availability of structural information on protein-protein complexes, deciphering their complex topology remains an outstanding challenge. Raf kinase inhibitory protein (RKIP) has gained substantial attention as a favorable molecular target for numerous pathologies including cancer and Alzheimer’s disease. RKIP interferes with the RAF/MEK/ERK signaling cascade by endogenously binding with C-Raf (Raf-1 kinase) and preventing its activation. In the current investigation, the binding of RKIP with C-Raf was explored by knowledge-based protein-protein docking web-servers including HADDOCK and ZDOCK and a consensus binding mode of C-Raf/RKIP structural complex was obtained. Molecular dynamics (MD) simulations were further performed in an explicit solvent to sample the conformations for when RKIP binds to C-Raf. Some of the conserved interface residues were mutated to alanine, phenylalanine and leucine and the impact of mutations was estimated by additional MD simulations and MM/PBSA analysis for the wild-type (WT) and constructed mutant complexes. Substantial decrease in binding free energy was observed for the mutant complexes as compared to the binding free energy of WT C-Raf/RKIP structural complex. Furthermore, a considerable increase in average backbone root mean square deviation and fluctuation was perceived for the mutant complexes. Moreover, per-residue energy contribution analysis of the equilibrated simulation trajectory by HawkDock and ANCHOR web-servers was conducted to characterize the key residues for the complex formation. One residue each from C-Raf (Arg398) and RKIP (Lys80) were identified as the druggable “hot spots” constituting the core of the binding interface and corroborated by additional long-time scale (300 ns) MD simulation of Arg398Ala mutant complex. A notable conformational change in Arg398Ala mutant occurred near the mutation site as compared to the equilibrated C-Raf/RKIP native state conformation and an essential hydrogen bonding interaction was lost. The thirteen binding sites assimilated from the overall analysis were mapped onto the complex as surface and divided into active and allosteric binding sites, depending on their location at the interface. The acquired information on the predicted 3D structural complex and the detected sites aid as promising targets in designing novel inhibitors to block the C-Raf/RKIP interaction.


2020 ◽  
Author(s):  
Josh Smith ◽  
Jim Pfaendtner

AbstractProtein bound uremic toxins (PBUTs) are known to bind strongly with the primary drug carrying sites of human serum albumin (HSA), Sudlow site I and Sudlow site II. A detailed energetic and structural description of PBUT interactions with these binding sites would provide useful insight into the design of materials that specifically displace and capture PBUTs. In this work, we used molecular dynamics (MD) simulations to study in atomistic detail 4 PBUTs bound in Sudlow site II. Specifically, we used the experimentally resolved X-ray structure of simulated indoxyl sulfate (IS) bound to Sudlow site II (PBD ID: 2BXH) to generate initial binding poses for p-cresyl sulfate (pCS), indole-3-acetic acid (IAA), and hippuric acid (HA). We calculated the interaction energy between toxin and protein in MD simulations and performed mean shift clustering on the collection of molecular structures from MD to identify the primary binding modes of each toxin. We find that all 4 toxins are primarily stabilized by electrostatic interactions between their anionic moiety and the hydrophilic residues in Sudlow site II. We observed transience in the strongest toxin-protein interaction, a charge-pairing with the positively charged R410 residue. We confirm the finding that the primary binding pose of IS in Sudlow site II is stabilized by a hydrogen bond with the carbonyl oxygen of L430, and find that this is also true for IAA. We provide insight into the chemical functional groups that might be incorporated to improve the specificity of synthetic materials for PBUT capture. This work represents a next step toward the de novo design of solutions to the problem of PBUT management in CKD patients.Significance StatementIn spite of their implication in poor clinical outcomes, surprisingly little information is available about the structure and mechanisms that govern the binding of protein bound uremic toxins to their primary carrier human serum albumin. To date, only the structure of indoxyl sulfate has been determined by experiment. This paper describes a comprehensive characterization of four toxins that are known to bind Sudlow site II using molecular dynamics simulations. Based on the experimental structure of indoxyl sulfate bound to HSA, the binding mode within Sudlow site II of three additional PBUTs was determined. The structures, energetic and mechanistic analysis provide substantial new information for the nephrology community about these toxins as well as new protocols to aid future studies of PBUTs.


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