Mechanical Unfolding of TNfn3: The Unfolding Pathway of a fnIII Domain Probed by Protein Engineering, AFM and MD Simulation

2005 ◽  
Vol 350 (4) ◽  
pp. 776-789 ◽  
Author(s):  
Sean P. Ng ◽  
Ross W.S. Rounsevell ◽  
Annette Steward ◽  
Christian D. Geierhaas ◽  
Philip M. Williams ◽  
...  
2019 ◽  
Vol 476 (24) ◽  
pp. 3835-3847 ◽  
Author(s):  
Aliyath Susmitha ◽  
Kesavan Madhavan Nampoothiri ◽  
Harsha Bajaj

Most Gram-positive bacteria contain a membrane-bound transpeptidase known as sortase which covalently incorporates the surface proteins on to the cell wall. The sortase-displayed protein structures are involved in cell attachment, nutrient uptake and aerial hyphae formation. Among the six classes of sortase (A–F), sortase A of S. aureus is the well-characterized housekeeping enzyme considered as an ideal drug target and a valuable biochemical reagent for protein engineering. Similar to SrtA, class E sortase in GC rich bacteria plays a housekeeping role which is not studied extensively. However, C. glutamicum ATCC 13032, an industrially important organism known for amino acid production, carries a single putative sortase (NCgl2838) gene but neither in vitro peptide cleavage activity nor biochemical characterizations have been investigated. Here, we identified that the gene is having a sortase activity and analyzed its structural similarity with Cd-SrtF. The purified enzyme showed a greater affinity toward LAXTG substrate with a calculated KM of 12 ± 1 µM, one of the highest affinities reported for this class of enzyme. Moreover, site-directed mutation studies were carried to ascertain the structure functional relationship of Cg-SrtE and all these are new findings which will enable us to perceive exciting protein engineering applications with this class of enzyme from a non-pathogenic microbe.


Acta Naturae ◽  
2010 ◽  
Vol 2 (3) ◽  
pp. 47-61 ◽  
Author(s):  
V I Tishkov ◽  
S S Savin ◽  
A S Yasnaya

2020 ◽  
Author(s):  
Sahar Qazi ◽  
Mustafa Alhaji Isa ◽  
Adam Mustapha ◽  
Khalid Raza ◽  
Ibrahim Alkali Allamin ◽  
...  

<p>The Severe Acute Respiratory Syndrome 2 (SARS-CoV-2) is an infectious virus that causes mild to severe life-threatening upper respiratory tract infection. The virus emerged in Wuhan, China in 2019, and later spread across the globe. Its genome has been completely sequenced and based on the genomic information, the virus possessed 3C-Like Main Protease (3CLpro), an essential multifunctional enzyme that plays a vital role in the replication and transcription of the virus by cleaving polyprotein at eleven various sites to produce different non-structural proteins. This makes the protein an important target for drug design and discovery. Herein, we analyzed the interaction between the 3CLpro and potential inhibitory compounds identified from the extracts of <i>Zingiber offinale</i> and <i>Anacardium occidentale</i> using in silico docking and Molecular Dynamics (MD) Simulation. The crystal structure of SARS-CoV-2 main protease in complex with 02J (5-Methylisoxazole-3-carboxylic acid) and PEJ (composite ligand) (PDB Code: 6LU7,2.16Å) retrieved from Protein Data Bank (PDB) and subject to structure optimization and energy minimization. A total of twenty-nine compounds were obtained from the extracts of <i>Zingiber offinale </i>and the leaves of <i>Anacardium occidentale. </i>These compounds were screened for physicochemical (Lipinski rule of five, Veber rule, and Egan filter), <i>Pan</i>-Assay Interference Structure (PAINS), and pharmacokinetic properties to determine the Pharmaceutical Active Ingredients (PAIs). Of the 29 compounds, only nineteen (19) possessed drug-likeness properties with efficient oral bioavailability and less toxicity. These compounds subjected to molecular docking analysis to determine their binding energies with the 3CLpro. The result of the analysis indicated that the free binding energies of the compounds ranged between ˗5.08 and -10.24kcal/mol, better than the binding energies of 02j (-4.10kcal/mol) and PJE (-5.07kcal.mol). Six compounds (CID_99615 = -10.24kcal/mol, CID_3981360 = 9.75kcal/mol, CID_9910474 = -9.14kcal/mol, CID_11697907 = -9.10kcal/mol, CID_10503282 = -9.09kcal/mol and CID_620012 = -8.53kcal/mol) with good binding energies further selected and subjected to MD Simulation to determine the stability of the protein-ligand complex. The results of the analysis indicated that all the ligands form stable complexes with the protein, although, CID_9910474 and CID_10503282 had a better stability when compared to other selected phytochemicals (CID_99615, CID_3981360, CID_620012, and CID_11697907). </p>


2020 ◽  
Author(s):  
Sahar Qazi ◽  
Mustafa Alhaji Isa ◽  
Adam Mustapha ◽  
Khalid Raza ◽  
Ibrahim Alkali Allamin ◽  
...  

<p>The Severe Acute Respiratory Syndrome 2 (SARS-CoV-2) is an infectious virus that causes mild to severe life-threatening upper respiratory tract infection. The virus emerged in Wuhan, China in 2019, and later spread across the globe. Its genome has been completely sequenced and based on the genomic information, the virus possessed 3C-Like Main Protease (3CLpro), an essential multifunctional enzyme that plays a vital role in the replication and transcription of the virus by cleaving polyprotein at eleven various sites to produce different non-structural proteins. This makes the protein an important target for drug design and discovery. Herein, we analyzed the interaction between the 3CLpro and potential inhibitory compounds identified from the extracts of <i>Zingiber offinale</i> and <i>Anacardium occidentale</i> using in silico docking and Molecular Dynamics (MD) Simulation. The crystal structure of SARS-CoV-2 main protease in complex with 02J (5-Methylisoxazole-3-carboxylic acid) and PEJ (composite ligand) (PDB Code: 6LU7,2.16Å) retrieved from Protein Data Bank (PDB) and subject to structure optimization and energy minimization. A total of twenty-nine compounds were obtained from the extracts of <i>Zingiber offinale </i>and the leaves of <i>Anacardium occidentale. </i>These compounds were screened for physicochemical (Lipinski rule of five, Veber rule, and Egan filter), <i>Pan</i>-Assay Interference Structure (PAINS), and pharmacokinetic properties to determine the Pharmaceutical Active Ingredients (PAIs). Of the 29 compounds, only nineteen (19) possessed drug-likeness properties with efficient oral bioavailability and less toxicity. These compounds subjected to molecular docking analysis to determine their binding energies with the 3CLpro. The result of the analysis indicated that the free binding energies of the compounds ranged between ˗5.08 and -10.24kcal/mol, better than the binding energies of 02j (-4.10kcal/mol) and PJE (-5.07kcal.mol). Six compounds (CID_99615 = -10.24kcal/mol, CID_3981360 = 9.75kcal/mol, CID_9910474 = -9.14kcal/mol, CID_11697907 = -9.10kcal/mol, CID_10503282 = -9.09kcal/mol and CID_620012 = -8.53kcal/mol) with good binding energies further selected and subjected to MD Simulation to determine the stability of the protein-ligand complex. The results of the analysis indicated that all the ligands form stable complexes with the protein, although, CID_9910474 and CID_10503282 had a better stability when compared to other selected phytochemicals (CID_99615, CID_3981360, CID_620012, and CID_11697907). </p>


Author(s):  
Acharya Balkrishna ◽  
Rashmi Mittal ◽  
Vedpriya Arya

Background:: COVID-19 caused by SARS-CoV-2 has been declared as global pandemic by WHO. Comprehensive analysis of this unprecedented outbreak may help to fight against the disease and may play a pivotal role in decreasing the mortality rate linked with it. Papain like protease (PLpro), a multifunctional polyprotein facilitates the replication of SARS-CoV-2 and evades it from the host immunological response by antagonizing cytokines, interferons and may be considered as potential drug target to combat the current pandemic. Methods:: Natural moieties obtained from medicinal plants were analysed for their potency to target PLpro of SARS-CoV-2 by molecular docking study and were compared with synthetic analogs named as remdesivir, chloroquine and favipiravir. The stability of complexes of top hits was analysed by MD Simulation and interaction energy was calculated. Furthermore, average RMSD values were computed and deepsite ligand binding pockets were predicted using Play Molecule. Drug like abilities of these moieties were determined using ADMET and bond distance between the ligand and active site was assessed to predict the strength of interaction. Results:: Nimbocinol (-7.6 Kcal/mol) and sage (-7.3 Kcal/mol) exhibited maximum BA against PLpro SARS-CoV-2 as evident from molecular docking study which was found to be even better than remdesivir (-6.1 Kcal/mol), chloroquine (-5.3 Kcal/mol) and favipiravir (-5.7 Kcal/mol). Both nimbocinol-PLpro and sage-PLpro SARS-CoV-2 complex exhibited stable conformation during MD Simulation of 101ns at 310 K and potential, kinetic and electrostatic interaction energies were computed which was observed to be concordant with results of molecular docking study. RMSD average values were found to be 0.496 ± 0.015 Å and 0.598 ± 0.023 Å for nimbocinol and sage respectively thus revealing that both the deviation and fluctuations during MD Simulation were observed to be least. Deepsite prediction disclosed that both compounds occupied cryptic pockets in receptor and non-bond distance analysis revealed the formation of hydrogen bonds during ligand-receptor interaction. ADMET exploration further validated the drug like properties of these compounds. Conclusion:: Present study revealed that active constituents of Azadirachta indica and Salvia officinalis can be potentially used to target SARS-CoV-2 by hindering its replication process.


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