scholarly journals The ‘natural’ hybrid haemoglobin from mule. Interrelationships with its parent haemoglobins from horse and donkey

1992 ◽  
Vol 282 (2) ◽  
pp. 595-599 ◽  
Author(s):  
S G Condò ◽  
M Coletta ◽  
R Cicchetti ◽  
G Argentin ◽  
P Guerrieri ◽  
...  
Keyword(s):  
Free Energy ◽  
Binding Free Energy ◽  
Binding Mode ◽  
Natural Hybrid ◽  
Binding Properties ◽  
Inositol Hexakisphosphate ◽  
Physiological Conditions ◽  
General Terms ◽  
O2 Binding

The equilibrium O2-binding properties of the hybrid haemoglobin (Hb) present in vivo in erythrocytes from mule and of its parent Hbs from horse and donkey were compared with special reference to the effect of heterotropic ligands such as Cl-, D-glycerate 2,3-bisphosphate (DPG) and inositol hexakisphosphate. All these Hbs display a decreased effect by polyphosphates, confirming that what has been observed for horse Hb [Giardina, Brix, Clementi, Scatena, Nicoletti, Cicchetti, Argentin & Condò (1990) Biochem. J. 266, 897-900] is common to other equine species, at least from a qualitative standpoint. However, different quantitative aspects can be detected, which can be accounted for by a different role for the two types of chain in characterizing the binding free energy for the various heterotropic effectors. In particular, it is shown that the binding mode of DPG and inositol hexakisphosphate displays different features since long-range effects can be observed clearly for inositol hexakisphosphate but not for DPG. In general terms, in spite of a different intrinsic O2 affinity, the modulation of functional properties by third ligands leads these Hbs to behave, under physiological conditions, similarly to human HbA. It might represent an interesting example of how different species with similar functional needs find different ways to produce a similar functional behaviour.

Application of the ESMACS Binding Free Energy Protocol to a Highly Varied Ligand Dataset: Lactate Dehydogenase A

2019 ◽  
Author(s):  
David Wright ◽  
Fouad Husseini ◽  
Shunzhou Wan ◽  
Christophe Meyer ◽  
Herman Van Vlijmen ◽  
...  
Keyword(s):  
Free Energy ◽  
Surface Area ◽  
Binding Free Energy ◽  
Normal Mode Analysis ◽  
Binding Mode ◽  
Accessible Surface Area ◽  
Solvent Accessible Surface Area ◽  
Mode Analysis ◽  
Energy Calculation ◽  
Accessible Surface

<div>Here, we evaluate the performance of our range of ensemble simulation based binding free energy calculation protocols, called ESMACS (enhanced sampling of molecular dynamics with approximation of continuum solvent) for use in fragment based drug design scenarios. ESMACS is designed to generate reproducible binding affinity predictions from the widely used molecular mechanics Poisson-Boltzmann surface area (MMPBSA) approach. We study ligands designed to target two binding pockets in the lactate dehydogenase A target protein, which vary in size, charge and binding mode. When comparing to experimental results, we obtain excellent statistical rankings across this highly diverse set of ligands. In addition, we investigate three approaches to account for entropic contributions not captured by standard MMPBSA calculations: (1) normal mode analysis, (2) weighted solvent accessible surface area (WSAS) and (3) variational entropy. </div>

In-silico Design, ADMET Screening, MM-GBSA Binding Free Energy of Some Novel Isoxazole Substituted 9-Anilinoacridines as HER2 Inhibitors Targeting Breast Cancer

2019 ◽  
Vol 11 (2) ◽  
pp. 118-128 ◽  
Author(s):  
Rajagopal Kalirajan ◽  
Arumugasamy Pandiselvi ◽  
Byran Gowramma ◽  
Pandiyan Balachandran
Keyword(s):  
Breast Cancer ◽  
Free Energy ◽  
In Silico ◽  
Therapeutic Potential ◽  
Binding Free Energy ◽  
Breast Cancers ◽  
Molecular Docking Study ◽  
In Silico Admet

Background: Human Epidermal development factor Receptor-2 (HER2) is a membrane tyrosine kinase which is overexpressed and gene amplified in human breast cancers. HER2 amplification and overexpression have been linked to important tumor cell proliferation and survival pathways for 20% of instances of breast cancer. 9-aminoacridines are significant DNA-intercalating agents because of their antiproliferative properties. Objective: Some novel isoxazole substituted 9-anilinoacridines(1a-z) were designed by in-silico technique for their HER2 inhibitory activity. Docking investigations of compounds 1a-z are performed against HER2 (PDB id-3PP0) by using Schrodinger suit 2016-2. Methods: Molecular docking study for the designed molecules 1a-z are performed by Glide module, in-silico ADMET screening by QikProp module and binding free energy by Prime-MMGBSA module of Schrodinger suit. The binding affinity of designed molecules 1a-z towards HER2 was chosen based on GLIDE score. Results: Many compounds showed good hydrophobic communications and hydrogen bonding associations to hinder HER2. The compounds 1a-z, aside from 1z have significant Glide scores in the scope of - 4.91 to - 10.59 when compared with the standard Ethacridine (- 4.23) and Tamoxifen (- 3.78). The in-silico ADMET properties are inside the suggested about drug likeness. MM-GBSA binding of the most intense inhibitor is positive. Conclusion: The outcomes reveal that this study provides evidence for the consideration of isoxazole substituted 9-aminoacridine derivatives as potential HER2 inhibitors. The compounds, 1s,x,v,a,j,r with significant Glide scores may produce significant anti breast cancer activity and further in vitro and in vivo investigations may prove their therapeutic potential.

scholarly journals Interaction of Coumarin Phytoestrogens with ERα and ERβ: A Molecular Dynamics Simulation Study

Molecules ◽  
2020 ◽  
Vol 25 (5) ◽  
pp. 1165 ◽  
Author(s):  
Ting Wang ◽  
Yunfei Wang ◽  
Xuming Zhuang ◽  
Feng Luan ◽  
Chunyan Zhao ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Free Energy ◽  
Binding Free Energy ◽  
Human Life ◽  
Simulation Method ◽  
Binding Mode ◽  
Dynamics Simulation ◽  
Molecular Dynamics Methods ◽  
17Β Estradiol ◽  
The Stability

Coumarin phytoestrogens, as one of the important classes of phytoestrogens, have been proved to play an important role in various fields of human life. In this study, molecular simulation method including molecular docking and molecular dynamics methods were performed to explore the various effects between four classical coumarin phytoestrogens (coumestrol, 4-methoxycoumestrol, psoralen and isopsoralen), and estrogen receptors (ERα, ERβ), respectively. The calculated results not only proved that the four coumarin phytoestrogens have weaker affinity than 17β-estradiol to both ERα, and ERβ, but also pointed out that the selective affinity for ERβ is greater than ERα. In addition, the binding mode indicated that the formation of hydrogen bond and hydrophobic interaction have an important effect on the stability of the complexes. Further, the calculation and decomposition of binding free energy explored the main contribution interactions to the total free energy.

Application of the ESMACS Binding Free Energy Protocol to a Highly Varied Ligand Dataset: Lactate Dehydogenase A

2019 ◽  
Author(s):  
David Wright ◽  
Fouad Husseini ◽  
Shunzhou Wan ◽  
Christophe Meyer ◽  
Herman Van Vlijmen ◽  
...  
Keyword(s):  
Free Energy ◽  
Surface Area ◽  
Binding Free Energy ◽  
Normal Mode Analysis ◽  
Binding Mode ◽  
Accessible Surface Area ◽  
Solvent Accessible Surface Area ◽  
Mode Analysis ◽  
Energy Calculation ◽  
Accessible Surface

<div>Here, we evaluate the performance of our range of ensemble simulation based binding free energy calculation protocols, called ESMACS (enhanced sampling of molecular dynamics with approximation of continuum solvent) for use in fragment based drug design scenarios. ESMACS is designed to generate reproducible binding affinity predictions from the widely used molecular mechanics Poisson-Boltzmann surface area (MMPBSA) approach. We study ligands designed to target two binding pockets in the lactate dehydogenase A target protein, which vary in size, charge and binding mode. When comparing to experimental results, we obtain excellent statistical rankings across this highly diverse set of ligands. In addition, we investigate three approaches to account for entropic contributions not captured by standard MMPBSA calculations: (1) normal mode analysis, (2) weighted solvent accessible surface area (WSAS) and (3) variational entropy. </div>

scholarly journals Nelfinavir was predicted to be a potential inhibitor of 2019-nCov main protease by an integrative approach combining homology modelling, molecular docking and binding free energy calculation

2020 ◽  
Author(s):  
Zhijian Xu ◽  
Cheng Peng ◽  
Yulong Shi ◽  
Zhengdan Zhu ◽  
Kaijie Mu ◽  
...  
Keyword(s):  
Free Energy ◽  
Binding Free Energy ◽  
Homology Modelling ◽  
Binding Mode ◽  
Free Energy Calculations ◽  
Integrative Approach ◽  
Energy Calculation ◽  
Potential Inhibitor ◽  
Small Molecule Drugs ◽  
Main Protease

Abstract2019-nCov has caused more than 80 deaths as of 27 January 2020 in China, and infection cases have been reported in more than 10 countries. However, there is no approved drug to treat the disease. 2019-nCov Mpro is a potential drug target to combat the virus. We built homology models based on SARS Mpro structures, and docked 1903 small molecule drugs to the models. Based on the docking score and the 3D similarity of the binding mode to the known Mpro ligands, 4 drugs were selected for binding free energy calculations. Both MM/GBSA and SIE methods voted for nelfinavir, with the binding free energy of −24.69±0.52 kcal/mol and −9.42±0.04 kcal/mol, respectively. Therefore, we suggested that nelfinavir might be a potential inhibitor against 2019-nCov Mpro.

scholarly journals The HSP90 binding mode of a radicicol-like E-oxime determined by docking, binding free energy estimations, and NMR 15N chemical shifts

2009 ◽  
Vol 143 (3) ◽  
pp. 111-123 ◽  
Author(s):  
Martin Spichty ◽  
Antoine Taly ◽  
Franz Hagn ◽  
Horst Kessler ◽  
Sofia Barluenga ◽  
...  
Keyword(s):  
Free Energy ◽  
Binding Free Energy ◽  
Chemical Shifts ◽  
Binding Mode

scholarly journals Ligand deconstruction: Why some fragment binding positions are conserved and others are not

2015 ◽  
Vol 112 (20) ◽  
pp. E2585-E2594 ◽  
Author(s):  
Dima Kozakov ◽  
David R. Hall ◽  
Stefan Jehle ◽  
Lingqi Luo ◽  
Stefan O. Ochiana ◽  
...  
Keyword(s):  
Free Energy ◽  
Ligand Binding ◽  
Binding Free Energy ◽  
Hot Spot ◽  
Binding Mode ◽  
Binding Potential ◽  
Binding Modes ◽  
Affinity Ligand ◽  
Ligand Binding Sites ◽  
Free Energy Of Binding

Fragment-based drug discovery (FBDD) relies on the premise that the fragment binding mode will be conserved on subsequent expansion to a larger ligand. However, no general condition has been established to explain when fragment binding modes will be conserved. We show that a remarkably simple condition can be developed in terms of how fragments coincide with binding energy hot spots—regions of the protein where interactions with a ligand contribute substantial binding free energy—the locations of which can easily be determined computationally. Because a substantial fraction of the free energy of ligand binding comes from interacting with the residues in the energetically most important hot spot, a ligand moiety that sufficiently overlaps with this region will retain its location even when other parts of the ligand are removed. This hypothesis is supported by eight case studies. The condition helps identify whether a protein is suitable for FBDD, predicts the size of fragments required for screening, and determines whether a fragment hit can be extended into a higher affinity ligand. Our results show that ligand binding sites can usefully be thought of in terms of an anchor site, which is the top-ranked hot spot and dominates the free energy of binding, surrounded by a number of weaker satellite sites that confer improved affinity and selectivity for a particular ligand and that it is the intrinsic binding potential of the protein surface that determines whether it can serve as a robust binding site for a suitably optimized ligand.

scholarly journals Ligand binding to telomeric G-quadruplex DNA investigated by funnel-metadynamics simulations

2017 ◽  
Vol 114 (11) ◽  
pp. E2136-E2145 ◽  
Author(s):  
Federica Moraca ◽  
Jussara Amato ◽  
Francesco Ortuso ◽  
Anna Artese ◽  
Bruno Pagano ◽  
...  
Keyword(s):  
Free Energy ◽  
Ligand Binding ◽  
Rational Design ◽  
Binding Free Energy ◽  
Binding Mode ◽  
Dna Interaction ◽  
Accurate Estimate ◽  
Binding Modes ◽  
Binding Mechanism ◽  
Promoter Regions

G-quadruplexes (G4s) are higher-order DNA structures typically present at promoter regions of genes and telomeres. Here, the G4 formation decreases the replicative DNA at each cell cycle, finally leading to apoptosis. The ability to control this mitotic clock, particularly in cancer cells, is fascinating and passes through a rational understanding of the ligand/G4 interaction. We demonstrate that an accurate description of the ligand/G4 binding mechanism is possible using an innovative free-energy method called funnel-metadynamics (FM), which we have recently developed to investigate ligand/protein interaction. Using FM simulations, we have elucidated the binding mechanism of the anticancer alkaloid berberine to the human telomeric G4 (d[AG3(T2AG3)3]), computing also the binding free-energy landscape. Two ligand binding modes have been identified as the lowest energy states. Furthermore, we have found prebinding sites, which are preparatory to reach the final binding mode. In our simulations, the ions and the water molecules have been explicitly represented and the energetic contribution of the solvent during ligand binding evaluated. Our theoretical results provide an accurate estimate of the absolute ligand/DNA binding free energy (ΔGb0 = −10.3 ± 0.5 kcal/mol) that we validated through steady-state fluorescence binding assays. The good agreement between the theoretical and experimental value demonstrates that FM is a most powerful method to investigate ligand/DNA interaction and can be a useful tool for the rational design also of G4 ligands.

scholarly journals Influence of Mg2+ ions on the interaction between 3,5-dicaffeoylquinic acid and HTLV-I integrase

2012 ◽  
Vol 17 (1) ◽  
pp. 5 ◽  
Author(s):  
Ángela Peña ◽  
Juvenal Yosa ◽  
Yesid Cuesta-Astroz ◽  
Orlando Acevedo ◽  
Leonardo Lareo ◽  
...  
Keyword(s):  
Free Energy ◽  
Rational Design ◽  
Catalytic Domain ◽  
Binding Free Energy ◽  
Homology Model ◽  
Binding Mode ◽  
Antiretroviral Drugs ◽  
Type I ◽  
Interaction Sites ◽  
Dicaffeoylquinic Acid

<strong>Objective</strong>. Using molecular simulation, we studied the influence of Mg2+ ions on the binding mode of HTLV-I Integrase (IN) catalytic domain (modeled by homology) with the 3,5- Dicaffeoylquinic Acid (DCQA). HTLV-I Integrase homology model was built using template-like crystallographic data of the IN catalytic domain solved for Avian Sarcoma Virus (VSA, pdb: 1VSD). <strong>Materials and</strong> <strong>methods</strong>. In order to analyze the role of Mg2+ in the interaction or coupling between 3,5-DCQA and Integrase, three models were created: i) in the absence of Mg2+ ions, ii) with a Mg2+ ion coordinated at Asp15 and Asp72 and iii) model with two Mg2+ ions coordinated at Asp15-Asp72 and Asp72-Glu108. Coupling force and binding free energy between 3,5-DCQA and HTLV-I IN were assessed in the three models. <strong>Results</strong>. The lowest docking score and free energy binding were obtained for the second model. Mg2+ ion strongly affected the coupling of the inhibitor 3,5-DCQA with HTLV-I catalytic domain of Integrase, thus revealing a strong interaction in the ligand-protein complex regardless of the ligand-catalytic interaction sites for all three models. <strong>Conclusion</strong>. Altogether, these results strengthen the hypothesis that the presence of one Mg2+ ion could enhance the interaction in the complex by decreasing free energy, therefore increasing the affinity. Moreover, we propose 3, 5-DCQA as an important pharmacophore in the rational design of new antiretroviral drugs.<br /><br /><strong>Key words</strong>: 3,5 -Dicaffeoylquinic Acid, Human T-Lymphotropic Type I (HTLV-1), Integrase (IN), Homology Model, Molecular Docking, Binding Free Energy, Mg2+ Ions.

MOLECULAR DYNAMICS AND FREE ENERGY ANALYSES OF ERK2–PYRAZOLYLPYRROLE INHIBITORS INTERACTIONS: INSIGHT INTO STRUCTURE-BASED LIGAND DESIGN

2009 ◽  
Vol 08 (05) ◽  
pp. 887-908 ◽  
Author(s):  
JIN-HUI ZHAN ◽  
XI ZHAO ◽  
XU-RI HUANG ◽  
CHIA-CHUNG SUN
Keyword(s):  
Molecular Dynamics ◽  
Free Energy ◽  
Electrostatic Interactions ◽  
Binding Free Energy ◽  
Signal Transduction Pathway ◽  
Binding Mode ◽  
Inhibitory Effect ◽  
Dynamics Simulation ◽  
Protein Motions ◽  
Extracellular Signal

The extracellular signal-regulated protein kinase 2 (ERK2) is a pivotal member involving in Ras/Raf/MEK/ERK signal transduction pathway, acting as a central point where multiple signaling pathways coalesce to drive transcription. The pyrazolylpyrrole compounds as ATP competitive inhibitors of ERK2 can bind target with a special binding mode and have higher inhibitory potency than other ERK2-inhibitors. We investigated the interaction mode of ERK2-inhibitor using molecular dynamics simulation. The molecular mechanics Poisson–Boltzmann surface area approach is used to calculate the binding free energy of ERK2 with pyrazolylpyrrole inhibitors to analyze the factors of improving the affinity. The results indicated that the electrostatic interactions play the most important role in keeping the stabilization of ERK2-inhibitor. The structural analyses showed that the protein motions can be controlled by changing the structures of inhibitors; furthermore, the full use of available space in the binding site by improving the flexibilities of inhibitors and introducing hydrophobic groups can increase the inhibitory effect.

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