CALCULATION OF PROTEIN–LIGAND BINDING FREE ENERGY USING SMOOTH REACTION PATH GENERATION (SRPG) METHOD: A COMPARISON OF THE EXPLICIT WATER MODEL, GB/SA MODEL AND DOCKING SCORE FUNCTION

Author(s):  
DAISUKE MITOMO ◽  
YOSHIFUMI FUKUNISHI ◽  
JUNICHI HIGO ◽  
HARUKI NAKAMURA
2020 ◽  
Author(s):  
E. Prabhu Raman ◽  
Thomas J. Paul ◽  
Ryan L. Hayes ◽  
Charles L. Brooks III

<p>Accurate predictions of changes to protein-ligand binding affinity in response to chemical modifications are of utility in small molecule lead optimization. Relative free energy perturbation (FEP) approaches are one of the most widely utilized for this goal, but involve significant computational cost, thus limiting their application to small sets of compounds. Lambda dynamics, also rigorously based on the principles of statistical mechanics, provides a more efficient alternative. In this paper, we describe the development of a workflow to setup, execute, and analyze Multi-Site Lambda Dynamics (MSLD) calculations run on GPUs with CHARMm implemented in BIOVIA Discovery Studio and Pipeline Pilot. The workflow establishes a framework for setting up simulation systems for exploratory screening of modifications to a lead compound, enabling the calculation of relative binding affinities of combinatorial libraries. To validate the workflow, a diverse dataset of congeneric ligands for seven proteins with experimental binding affinity data is examined. A protocol to automatically tailor fit biasing potentials iteratively to flatten the free energy landscape of any MSLD system is developed that enhances sampling and allows for efficient estimation of free energy differences. The protocol is first validated on a large number of ligand subsets that model diverse substituents, which shows accurate and reliable performance. The scalability of the workflow is also tested to screen more than a hundred ligands modeled in a single system, which also resulted in accurate predictions. With a cumulative sampling time of 150ns or less, the method results in average unsigned errors of under 1 kcal/mol in most cases for both small and large combinatorial libraries. For the multi-site systems examined, the method is estimated to be more than an order of magnitude more efficient than contemporary FEP applications. The results thus demonstrate the utility of the presented MSLD workflow to efficiently screen combinatorial libraries and explore chemical space around a lead compound, and thus are of utility in lead optimization.</p>


2021 ◽  
Author(s):  
Yuriy Khalak ◽  
Gary Tresdern ◽  
Matteo Aldeghi ◽  
Hannah Magdalena Baumann ◽  
David L. Mobley ◽  
...  

The recent advances in relative protein-ligand binding free energy calculations have shown the value of alchemical methods in drug discovery. Accurately assessing absolute binding free energies, although highly desired, remains...


2020 ◽  
Vol 100 ◽  
pp. 107648 ◽  
Author(s):  
Nguyen Thi Mai ◽  
Ngo Thi Lan ◽  
Thien Y Vu ◽  
Phuong Thi Mai Duong ◽  
Nguyen Thanh Tung ◽  
...  

2015 ◽  
Vol 143 (4) ◽  
pp. 045104 ◽  
Author(s):  
Corrinne M. Welch ◽  
Aerial N. Camden ◽  
Stephen A. Barr ◽  
Gary M. Leuty ◽  
Gary S. Kedziora ◽  
...  

2020 ◽  
Author(s):  
Son Tung Ngo ◽  
Nguyen Minh Tam ◽  
Pham Minh Quan ◽  
Trung Hai Nguyen

COVID-19 pandemic has killed millions of people worldwide since its outbreak in Dec 2019. The pandemic is caused by the SARS-CoV-2 virus whose main protease (Mpro) is a promising drug target since it plays a key role in viral proliferation and replication. Currently, designing an effective therapy is an urgent task, which requires accurately estimating ligand-binding free energy to the SARS-CoV-2 Mpro. However, it should be noted that the accuracy of a free energy method probably depends on the protein target. A highly accurate approach for some targets may fail to produce a reasonable correlation with experiment when a novel enzyme is considered as a drug target. Therefore, in this context, the ligand-binding affinity to SARS-CoV-2 Mpro was calculated via various approaches. The Autodock Vina (Vina) and Autodock4 (AD4) packages were manipulated to preliminary investigate the ligand-binding affinity and pose to the SARS-CoV-2 Mpro. The binding free energy was then refined using the fast pulling of ligand (FPL), linear interaction energy (LIE), molecular mechanics-Poission Boltzmann surface area (MM-PBSA), and free energy perturbation (FEP) methods. The benchmark results indicated that for docking calculations, Vina is more accurate than AD4 and for free energy methods, FEP is the most accurate followed by LIE, FPL and MM-PBSA (FEP > LIE > FPL > MM-PBSA). Moreover, the binding mechanism was also revealed by atomistic simulations. The vdW interaction is the dominant factor. The residues <i>Thr25</i>, <i>Thr26</i>, <i>His41</i>, <i>Ser46</i>, <i>Asn142</i>, <i>Gly143</i>, <i>Cys145</i>, <i>Glu166</i>, and <i>Gln189</i> are essential elements affecting on the binding process. Furthermore, the <i>Ser46</i> and related residues probably are important elements affecting the enlarge/dwindle of the SARS-CoV-2 Mpro binding cleft. The benchmark probably guide for further investigations using computational approaches.


2020 ◽  
Author(s):  
Mohammad Kawsar Sharif Siam ◽  
Mohammad Umer Sharif Shohan ◽  
Zaira Zafroon

AbstractMycobacterium tuberculosis, the leading bacterial killer disease worldwide, causes Human tuberculosis (TB). Due to the growing problem of drug resistant Mycobacterium tuberculosis strains, new anti-TB drugs are urgently needed. Natural sources such as plant extracts have long played an important role in tuberculosis management and can be used as a template to design new drugs. A wide screening of natural sources is time consuming but the process can be significantly sped up using molecular docking. In this study, we used a molecular docking approach to investigate the interactions between selected natural constituents and three proteins MtPanK, MtDprE1 and MtKasA involved in the physiological functions of Mycobacterium tuberculosis which are necessary for the bacteria to survive and cause disease. The molecular docking score, a score that accounts for the binding affinity between a ligand and a target protein, for each protein was calculated against 150 chemical constituents of different classes to estimate the binding free energy. The docking scores represent the binding free energy. The best docking scores indicates the highest ligand protein binding which is indicated by the lowest energy value. Among the natural constituents, Shermilamine B showed a docking score of - 8.5kcal/mol, Brachystamide B showed a docking score of −8.6 kcal/mol with MtPanK, Monoamphilectine A showed a score of −9.8kcal/mol with MtDprE1.These three compounds showed docking scores which were superior to the control inhibitors and represent the opportunity of in vitro biological evaluation and anti-TB drug design. Consequently, all these compounds belonged to the alkaloid class. Specific interactions were studied to further understand the nature of intermolecular bonds between the most active ligands and the protein binding site residues which proved that among the constituents monoamphilectine A and Shermilamine B show more promise as Anti-TB drugs. Furthermore, the ADMET properties of these compounds or ligands showed that they have no corrosive or carcinogenic parameters.Graphical Abstract


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