scholarly journals Molecular mechanisms for the adhesion of chitin and chitosan to montmorillonite clay

RSC Advances ◽  
2015 ◽  
Vol 5 (67) ◽  
pp. 54580-54588 ◽  
Author(s):  
Yan Wang ◽  
Jakob Wohlert ◽  
Malin Bergenstråhle-Wohlert ◽  
Yaoquan Tu ◽  
Hans Ågren

Molecular dynamics simulations were used to study the wet adhesion of chitin and chitosan oligomers to montmorillonite clay.

2004 ◽  
Vol 108 (30) ◽  
pp. 10678-10686 ◽  
Author(s):  
Fabrice Gardebien ◽  
Anouk Gaudel-Siri ◽  
Jean-Luc Brédas ◽  
Roberto Lazzaroni

2019 ◽  
Vol 11 (18) ◽  
pp. 2365-2380
Author(s):  
Aimen K Aljoundi ◽  
Clement Agoni ◽  
Fisayo A Olotu ◽  
Mahmoud ES Soliman

Aim: Blocking oncogenic signaling of B-cell receptor (BCR) has been explored as a viable strategy in the treatment of diffuse large B-cell lymphoma. Masitinib is shown to multitarget LYN, FYN and BLK kinases that propagate BCR signals to downstream effectors. However, the molecular mechanisms of its selectivity and pan-inhibition remain elusive. Materials & methods: This study therefore employed molecular dynamics simulations coupled with advanced post-molecular dynamics simulation techniques to unravel the structural mechanisms that inform the reported multitargeting ability of masitinib. Results: Molecular dynamics simulations revealed initial selective targeting of catalytic residues (Asp334/Glu335 – LYN; Asp130/Asp148/Glu54 – FYN; Asp89 – BLK) by masitinib, with high-affinity interactions via its piperazine ring at the entrance of the ATP-binding pockets, before systematic access into the hydrophobic deep pocket grooves. Conclusion: Identification of these ‘gatekeeper’ residues could open up a novel paradigm of structure-based design of highly selective pan-inhibitors of BCR signaling in the treatment of diffuse large B-cell lymphoma.


2019 ◽  
Vol 12 (1) ◽  
Author(s):  
K. K. Abelak ◽  
D. Bishop-Bailey ◽  
I. Nobeli

Abstract Objectives The data presented here is part of a study that was aimed at characterizing the molecular mechanisms of polyunsaturated fatty acid metabolism by CYP2J2, the main cytochrome P450 enzyme active in the human cardiovasculature. This part comprises the molecular dynamics simulations of the binding of three eicosanoid substrates to wild type and mutant forms of the enzyme. These simulations were carried out with the aim of dissecting the importance of individual residues in the active site and the roles they might play in dictating the binding and catalytic specificity exhibited by CYP2J2. Data description The data comprise: (a) a new homology model of CYP2J2, (b) a number of predicted low-energy complexes of CYP2J2 with arachidonic acid, docosahexaenoic acid and eicosapentaenoic acid, produced with molecular docking and (c) a series of molecular dynamics simulations of the wild type and four mutants interacting with arachidonic acid as well as simulations of the wild type interacting with the two other eicosanoid ligands. The simulations may be helpful in identifying the determinants of substrate specificity of this enzyme and in unraveling the role of individual mutations on its function. They may also help guide the generation of mutants with altered substrate preferences.


2021 ◽  
Vol 17 (3) ◽  
pp. e1008771
Author(s):  
Min Wu ◽  
Lyudmyla Dorosh ◽  
Gerold Schmitt-Ulms ◽  
Holger Wille ◽  
Maria Stepanova

Alzheimer’s disease is associated with the formation of toxic aggregates of amyloid beta (Aβ) peptides. Despite tremendous efforts, our understanding of the molecular mechanisms of aggregation, as well as cofactors that might influence it, remains incomplete. The small cyclic neuropeptide somatostatin-14 (SST14) was recently found to be the most selectively enriched protein in human frontal lobe extracts that binds Aβ42 aggregates. Furthermore, SST14’s presence was also found to promote the formation of toxic Aβ42 oligomers in vitro. In order to elucidate how SST14 influences the onset of Aβ oligomerization, we performed all-atom molecular dynamics simulations of model mixtures of Aβ42 or Aβ40 peptides with SST14 molecules and analyzed the structure and dynamics of early-stage aggregates. For comparison we also analyzed the aggregation of Aβ42 in the presence of arginine vasopressin (AVP), a different cyclic neuropeptide. We observed the formation of self-assembled aggregates containing the Aβ chains and small cyclic peptides in all mixtures of Aβ42–SST14, Aβ42–AVP, and Aβ40–SST14. The Aβ42–SST14 mixtures were found to develop compact, dynamically stable, but small aggregates with the highest exposure of hydrophobic residues to the solvent. Differences in the morphology and dynamics of aggregates that comprise SST14 or AVP appear to reflect distinct (1) regions of the Aβ chains they interact with; (2) the propensities to engage in hydrogen bonds with Aβ peptides; and (3) solvent exposures of hydrophilic and hydrophobic groups. The presence of SST14 was found to impede aggregation in the Aβ42–SST14 system despite a high hydrophobicity, producing a stronger “sticky surface” effect in the aggregates at the onset of Aβ42–SST14 oligomerization.


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