Electrostatic interactions play a pivotal role in the structure and mechanism of action of most biomolecules. There are several conceptually different methods to deal with electrostatics in molecular dynamics simulations. Ionic strength effects are usually introduced using such methodologies and can have a significant impact on the quality of the final conformation space obtained. We have previously shown that full system neutralization can lead to wrong lipidic phases in the 25% PA/PC bilayer (. 5483-5492). In this work, we investigate how two limit approaches to the ionic strength treatment (implicitly with GRF or using full system neutralization with either GRF or PME) can influence the conformational space of the second-generation PAMAM dendrimer. Constant-pH MD simulations were used to map PAMAM's conformational space at its full pH range (from 2.5 to 12.5). Our simulations clearly captured the coupling between protonation and conformation in PAMAM. Interestingly, the dendrimer conformational distribution was almost independent of the ionic strength treatment methods, which is in contrast to what we have observed in charged lipid bilayers. Overall, our results confirm that both GRF with implicit ionic strength and a fully neutralized system with PME are valid approaches to model charged globular systems, using the GROMOS 54A7 force field.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6045380 | PMC |
http://dx.doi.org/10.1021/acsomega.7b01708 | DOI Listing |
Int J Biol Macromol
January 2025
College of Materials Science and Engineering, Nanjing Tech University, Nanjing 211816, PR China. Electronic address:
The carboxymethyl chitosan (CMCS)-based porous beads are still criticized for their limited number of binding sites, which impairs their efficacy in removing aqueous pollutants. To overcome this challenge, this work introduces the production of covalently crosslinked CMCS-based beads containing SiO and poly(2-acrylamido-2-methylpropanesulfonic acid) (PAMPS). The porous composite beads not only possess remarkable stability under acidic conditions, but also have abundant active binding sites for adsorption.
View Article and Find Full Text PDFMol Pharm
January 2025
Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University, 8000 Utopia Parkway, Queens, New York 11439, United States.
Although glycine is the simplest of the amino acids, its solution and solid-state properties are far from straightforward. The aqueous solubility of glycine plays an important role in various applications, including nutrition, food products, biodegradable plastics, and drug development. There is evidence that glycine in subsaturated pH 3-8 solutions forms a dimer, as suggested by several techniques.
View Article and Find Full Text PDFSci Adv
January 2025
Department of Mechanical Engineering, University of Delaware, Newark, DE 19716, USA.
ACS Macro Lett
January 2025
Materials Department, University of California, Santa Barbara, California 93106, United States.
Solid polymer electrolytes (SPEs) with mechanical strength and reduced flammability may also enable next-generation Li batteries with higher energy densities. However, conventional SPEs have fundamental limitations in terms of Li conductivity. While an imidazole functionalized polymer (PMS-Im) has been previously shown to have ionic conductivity related to the imidazole-Li coordination, herein we demonstrate that quaternization of this polymer to form an analogous imidazolium functionalized polymer (PMS-Im) more efficiently solvates lithium salts and plasticizes the polymer.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
Department of Chemistry, University of Rajasthan, Jaipur, Rajasthan, India, 302004.
The present investigation delves into the redox reaction between -chlorophenol (-CP) and hexacyanoferrate(III) [HCF(III)], catalyzed by Ag(I) in an alkaline environment. Findings reveal a first-order dependence on both -CP and the oxidant, and the reaction rate showcased a first-order reaction towards Ag(I), which was further amplified by the medium as per the equation = + [OH]. Interestingly, the ionic strength remained unchanged throughout the reaction, exerting no discernible effect on the reaction rate.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!