scholarly journals Molecular Dynamics Simulations of Adsorption of Amino Acid Side Chain Analogues and a Titanium Binding Peptide on the TiO2 (100) Surface

2015 ◽  
Vol 119 (32) ◽  
pp. 18126-18139 ◽  
Author(s):  
Erik G. Brandt ◽  
Alexander P. Lyubartsev
Keyword(s):  
Molecular Dynamics ◽  
Amino Acid ◽  
Molecular Dynamics Simulations ◽  
Side Chain ◽  
Amino Acid Side Chain ◽  
Binding Peptide ◽  
Dynamics Simulations

scholarly journals Molecular Dynamics Simulations of a Cytochrome P450 from Tepidiphilus thermophilus (P450-TT) Reveal How Its Substrate-Binding Channel Opens

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3614
Author(s):  
Abayomi S. Faponle ◽  
Anupom Roy ◽  
Ayodeji A. Adelegan ◽  
James W. Gauld
Keyword(s):  
Crystal Structure ◽  
Molecular Dynamics ◽  
Cytochrome P450 ◽  
Amino Acid ◽  
Molecular Dynamics Simulations ◽  
Organic Molecules ◽  
Side Chain ◽  
Relative Solvent Accessibility ◽  
Amino Acid Residues ◽  
Dynamics Simulations

Cytochrome P450s (P450) are important enzymes in biology with useful biochemical reactions in, for instance, drug and xenobiotics metabolisms, biotechnology, and health. Recently, the crystal structure of a new member of the CYP116B family has been resolved. This enzyme is a cytochrome P450 (CYP116B46) from Tepidiphilus thermophilus (P450-TT) and has potential for the oxy-functionalization of organic molecules such as fatty acids, terpenes, steroids, and statins. However, it was thought that the opening to its hitherto identified substrate channel was too small to allow organic molecules to enter. To investigate this, we performed molecular dynamics simulations on the enzyme. The results suggest that the crystal structure is not relaxed, possibly due to crystal packing effects, and that its tunnel structure is constrained. In addition, the simulations revealed two key amino acid residues at the mouth of the channel; a glutamyl and an arginyl. The glutamyl’s side chain tightens and relaxes the opening to the channel in conjunction with the arginyl’s, though the latter’s side chain is less dramatically changed after the initial relaxation of its conformations. Additionally, it was observed that the effect of increased temperature did not considerably affect the dynamics of the enzyme fold, including the relative solvent accessibility of the amino acid residues that make up the substrate channel wall even as compared to the changes that occurred at room temperature. Interestingly, the substrate channel became distinguishable as a prominent tunnel that is likely to accommodate small- to medium-sized organic molecules for bioconversions. That is, P450-TT has the ability to pass appropriate organic substrates to its active site through its elaborate substrate channel, and notably, is able to control or gate any molecules at the opening to this channel.

Schistosomal Sulfotransferase Interaction with Oxamniquine Involves Hybrid Mechanism of Induced-fit and Conformational Selection

2020 ◽  
Vol 16 (4) ◽  
pp. 451-459 ◽  
Author(s):  
Fortunatus C. Ezebuo ◽  
Ikemefuna C. Uzochukwu
Keyword(s):  
Molecular Dynamics ◽  
Amino Acid ◽  
Binding Energy ◽  
Binding Site ◽  
Conformational Dynamics ◽  
Side Chain ◽  
Amino Acid Residues ◽  
Conformational Selection ◽  
Hybrid Mechanism ◽  
Dynamics Simulations

Background: Sulfotransferase family comprises key enzymes involved in drug metabolism. Oxamniquine is a pro-drug converted into its active form by schistosomal sulfotransferase. The conformational dynamics of side-chain amino acid residues at the binding site of schistosomal sulfotransferase towards activation of oxamniquine has not received attention. Objective: The study investigated the conformational dynamics of binding site residues in free and oxamniquine bound schistosomal sulfotransferase systems and their contribution to the mechanism of oxamniquine activation by schistosomal sulfotransferase using molecular dynamics simulations and binding energy calculations. Methods: Schistosomal sulfotransferase was obtained from Protein Data Bank and both the free and oxamniquine bound forms were subjected to molecular dynamics simulations using GROMACS-4.5.5 after modeling it’s missing amino acid residues with SWISS-MODEL. Amino acid residues at its binding site for oxamniquine was determined and used for Principal Component Analysis and calculations of side-chain dihedrals. In addition, binding energy of the oxamniquine bound system was calculated using g_MMPBSA. Results: The results showed that binding site amino acid residues in free and oxamniquine bound sulfotransferase sampled different conformational space involving several rotameric states. Importantly, Phe45, Ile145 and Leu241 generated newly induced conformations, whereas Phe41 exhibited shift in equilibrium of its conformational distribution. In addition, the result showed binding energy of -130.091 ± 8.800 KJ/mol and Phe45 contributed -9.8576 KJ/mol. Conclusion: The results showed that schistosomal sulfotransferase binds oxamniquine by relying on hybrid mechanism of induced fit and conformational selection models. The findings offer new insight into sulfotransferase engineering and design of new drugs that target sulfotransferase.

scholarly journals New CHARMM force field parameters for dehydrated amino acid residues, the key to lantibiotic molecular dynamics simulations

RSC Advances ◽  
2014 ◽  
Vol 4 (89) ◽  
pp. 48621-48631 ◽  
Author(s):  
Eleanor R. Turpin ◽  
Sam Mulholland ◽  
Andrew M. Teale ◽  
Boyan B. Bonev ◽  
Jonathan D. Hirst
Keyword(s):  
Molecular Dynamics ◽  
Amino Acid ◽  
Force Field ◽  
Molecular Dynamics Simulations ◽  
Amino Acid Residues ◽  
Charmm Force Field ◽  
Force Field Parameters ◽  
Dynamics Simulations

scholarly journals A Novel Quali-Quantitative Defect of VWF

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 1032-1032
Author(s):  
Tom Van De Berg ◽  
Alice Todaro ◽  
Joyce van Beers ◽  
Kanin Wichapong ◽  
Floor Heubel-Moenen ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Amino Acid ◽  
Genetic Analysis ◽  
Molecular Dynamics Simulations ◽  
Mrna Level ◽  
Bleeding Tendency ◽  
Unknown Significance ◽  
Dynamics Simulations ◽  
Von Willebrand

Abstract Background Von Willebrand Factor (VWF) is a multimeric protein largely involved in both primary and secondary hemostasis. The diagnosis and classification of von Willebrand Disease (VWD) patients can be challenging. In this poster we explore the genetic defects and their structural consequences in a VWD patient with a disproportionately high bleeding phenotype for her VWD severity. A 31-year old female, initially diagnosed with VWD type 1, presented herself with a bleeding tendency (ISTH-BAT 13) disproportionate to the severity of her VWD with antigen levels of 36%. Additional analysis showed decreased FVIII-binding at 28%. The combination of both quantitative and functional defects of VWF was an indication for further genetic analysis in order to better define the subtype of VWD. Aims Genetic and structural analysis of VWF in a patient with a disproportionally high bleeding phenotype with regard to a mild decrease in VWF antigen. Methods Routine laboratory analysis for VWD was performed. Genetic screening was performed by exome sequencing of hemostasis related genes. VWF mRNA analysis was carried out by RT-PCR and Sanger sequencing. The X-ray structure of furin in complex with a peptide-based inhibitor (PDB ID: 6YD7) was used as a template to construct furin-VWF (759HR(R760S)SKRS764) complex. The derived structures (furin in complex with WT/R760S-VWF) were subjected to molecular dynamics (MD) simulations (200ns) and binding free energy (BFE) calculations by using standard parameters and protocols implemented in AMBER20 program. Results Routine analysis showed PFA-ADP and PFA EPI >300 seconds, VWF:ACT of 37% with a VWF:AG of 36%. Collagen binding and FVIII-binding were 46% and 28% respectively. Genetic analysis of the VWF gene disclosed 2 heterozygous variants of unknown significance (VUS): c.2771 G>A (exon 21, p.Arg924Gln) has a 1-2.5% population prevalence and has been previously described in type 1 and 2N VWD. The other VUS (c.2278 C>A; exon 17) is a novel mutation predicting a major amino acid substitution (p.Arg760Ser) in the D2-domain of VWF. Sequencing of exons 17 and 21 in the patient's VWF mRNA revealed homozygosity for the mutated allele at both mutation sites, indicating that the two variants are in cis and that the 'normal' allele is not expressed at mRNA level. Molecular dynamics simulations of the novel c.2278 C>A mutation (Arg760Ser) predicts a markedly decreased binding of furin to its VWF binding site, possibly decreasing or preventing VWF pro-peptide cleavage. This in turn has been shown to lead to reduced FVIII-binding of VWF. Conclusion Genetic analysis shows one polymorphism (c.2771 G>A) and one variation of unknown significance (c.2278 C>A) in the patient's VWF-gene. The polymorphism is known to be of low pathogenicity. The c. 2278 C>A mutation was not known in any of the mutation databases and is a novel VWF mutation. Both mutations were shown to be present on the same allele. As the wild-type allele was not expressed on mRNA level, all of the patient's VWF protein includes both amino acid substitutions. Modeling and molecular dynamics simulations show a markedly decreased affinity of furin to its cleavage site on the VWF protein due to the Arg760Ser substitution, likely resulting in a persistent pro-peptide binding to the mature VWF protein. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

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