scholarly journals Stability and Mobility of Lid Lipmnk in Acetonitrile by Molecular Dynamics Simulations Approach

2018 ◽  
Vol 15 (2) ◽  
pp. 295-299
Author(s):  
Dian Herasari ◽  
Rukman Hertadi ◽  
Fida M. Warganegara ◽  
Akhmaloka Akhmaloka
Keyword(s):  
Molecular Dynamics ◽  
Conformational Dynamics ◽  
Solvent Polarity ◽  
Thermophilic Bacterium ◽  
Solvent Mixtures ◽  
The Stability ◽  
Dynamics Simulations ◽  
Opening And Closing ◽  
Acetonitrile Concentration ◽  
Detailed Molecular Analysis

Manuk lipase (lipMNK) from the thermophilic bacterium Geobacillus sp is a double lid lipase containing short and long lid segments. A few studies demonstrated that catalytic action of lipase involved the movement of lid segments from closed to open conformation upon the substrate binding. One factor that affects conformational dynamics of the lid segments is solvent polarity. The presence of acetonitrile in certain concentration has showed to enhance lipase activity. In this study, the effect of acetonitrile to the stability and activity of lipMNK was studied at the atomic level by molecular dynamics (MD) simulation. MD was carried out by NPT ensemble at 358 K for 100 nano seconds in various ratio of acetonitrile:water solvent mixtures. The results showed that the conformation of lipMNK was stable up to 70%. However, the effect of lid movement was significantly observed since the concentration at 20% acetonitrile. Detailed molecular analysis at this acetonitrile concentration revealed that the two lids moved in different modes upon opening and closing movement. In the opening movement, the two lids appeared to move in almost simultaneously, while during the closing movement, it was observed sequentially, started by short segment followed by long segment lid.

Molecular Basis of Glucose Transport Mechanism in Plants

2019 ◽  
Author(s):  
Balaji Selvam ◽  
Ya-Chi Yu ◽  
Liqing Chen ◽  
Diwakar Shukla
Keyword(s):  
Molecular Dynamics ◽  
Free Energy ◽  
Molecular Dynamics Simulations ◽  
Conformational Changes ◽  
Transport Mechanism ◽  
Conformational Dynamics ◽  
Site Directed Mutagenesis ◽  
Free Energy Barrier ◽  
Transport Cycle ◽  
Dynamics Simulations

<p>The SWEET family belongs to a class of transporters in plants that undergoes large conformational changes to facilitate transport of sugar molecules across the cell membrane. However, the structures of their functionally relevant conformational states in the transport cycle have not been reported. In this study, we have characterized the conformational dynamics and complete transport cycle of glucose in OsSWEET2b transporter using extensive molecular dynamics simulations. Using Markov state models, we estimated the free energy barrier associated with different states as well as 1 for the glucose the transport mechanism. SWEETs undergoes structural transition to outward-facing (OF), Occluded (OC) and inward-facing (IF) and strongly support alternate access transport mechanism. The glucose diffuses freely from outside to inside the cell without causing major conformational changes which means that the conformations of glucose unbound and bound snapshots are exactly same for OF, OC and IF states. We identified a network of hydrophobic core residues at the center of the transporter that restricts the glucose entry to the cytoplasmic side and act as an intracellular hydrophobic gate. The mechanistic predictions from molecular dynamics simulations are validated using site-directed mutagenesis experiments. Our simulation also revealed hourglass like intermediate states making the pore radius narrower at the center. This work provides new fundamental insights into how substrate-transporter interactions actively change the free energy landscape of the transport cycle to facilitate enhanced transport activity.</p>

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.

New molecular insights into the stability of Ni–Pd hollow nanoparticles

2017 ◽  
Vol 4 (10) ◽  
pp. 1679-1690 ◽  
Author(s):  
Hamed Akbarzadeh ◽  
Esmat Mehrjouei ◽  
Amir Nasser Shamkhali ◽  
Mohsen Abbaspour ◽  
Sirous Salemi ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Thermal Behavior ◽  
Molecular Dynamics Simulations ◽  
Structural Evolution ◽  
Hollow Nanoparticles ◽  
The Stability ◽  
Dynamics Simulations

Molecular dynamics simulations were used to investigate the structural evolution and thermal behavior of Ni–Pd hollow nanoparticles.

scholarly journals Molecular dynamics simulations reveal distinct differences in conformational dynamics and thermodynamics between the unliganded and CD4-bound states of HIV-1 gp120

2020 ◽  
Vol 22 (10) ◽  
pp. 5548-5560
Author(s):  
Yi Li ◽  
Lei Deng ◽  
Jing Liang ◽  
Guang-Heng Dong ◽  
Yuan-Ling Xia ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Bound States ◽  
Conformational Dynamics ◽  
Immunological Properties ◽  
Dynamics Simulations ◽  
Hiv Gp120 ◽  
Hiv 1

Large changes in dynamics and thermodynamics of gp120 upon CD4 binding account for the functional and immunological properties of HIV/gp120.

scholarly journals Conformational dynamics of a crystalline protein from microsecond-scale molecular dynamics simulations and diffuse X-ray scattering

2014 ◽  
Vol 111 (50) ◽  
pp. 17887-17892 ◽  
Author(s):  
Michael E. Wall ◽  
Andrew H. Van Benschoten ◽  
Nicholas K. Sauter ◽  
Paul D. Adams ◽  
James S. Fraser ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Conformational Dynamics ◽  
X Ray ◽  
X Ray Scattering ◽  
Dynamics Simulations ◽  
Ray Scattering
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