We investigated, by using all-atom molecular dynamics simulations, the effect of the outer membrane of Gram-negative bacteria, composed in the outer leaflet by polar/charged lipopolysaccharides (LPS), on the electrostatic properties of general porins from the Enterobacteriaceae family. General porins constitute the main path for the facilitated diffusion of polar antibiotics through the outer membrane. As model system we selected OmpK36 from Klebsiella pneumoniae, the ortholog of OmpC from Escherichia coli. This species presents high variability of amino acid composition of porins, with the effect to increase its resistance to the penetration of antibiotics. The various properties we analyzed seem to indicate that LPS acts as an independent layer without affecting the internal electrostatic properties of OmpK36. The only apparent effect on the microsecond time scale we sampled is the appearance of calcium ions, when present at moderate concentration in solution, inside the pore. However, we noticed increased fluctuations of the polarization density and only minor changes on its average value.
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http://dx.doi.org/10.1002/cphc.202400147 | DOI Listing |
Mater Horiz
January 2025
Institute of Biomedical Engineering, College of Medicine, Southwest Jiaotong University, Chengdu 610031, China.
Sci Rep
January 2025
State Key Laboratory of Structure Analysis, Optimization and CAE Software for Industrial Equipment, Department of Engineering Mechanics, Dalian University of Technology, Dalian, 116024, China.
The biocompatible autonomous self-healing hydrogels have great potential in biomedical applications. However, the fairly weak tensile strength of the hydrogels seriously hinders their application. Here, we introduced chitosan (CS) into the polyvinyl alcohol (PVA)-tannic acid (TA) hydrogel and investigated the effects of the CS content, as CS can not only form reversible H bonds with PVA and TA but also form reversible electrostatic interactions with TA.
View Article and Find Full Text PDFThe objective of the study was to examine the mechanical and electrostatic properties of poly(vinyl chloride) intended for use in protective footwear. The poly(vinyl chloride) material was made with graphite (flake side dimensions 5 and 10 µm) additive in weight concentration variants from 0.5 to 10.
View Article and Find Full Text PDFCommun Phys
December 2024
Institut für Theoretische Physik, TU Wien, Wiedner Hauptstraße 8-10, A-1040 Wien, Austria.
Despite the intrinsic charge heterogeneity of proteins plays a crucial role in the liquid-liquid phase separation (LLPS) of a broad variety of protein systems, our understanding of the effects of their electrostatic anisotropy is still in its early stages. We approach this issue by means of a coarse-grained model based on a robust mean-field description that extends the DLVO theory to non-uniformly charged particles. We numerically investigate the effect of surface charge patchiness and net particle charge on varying these features independently and with the use of a few parameters only.
View Article and Find Full Text PDFRSC Adv
January 2025
Graduate School of Environmental Symbiotic System Major, Nippon Institute of Technology 4-1 Gakuendai, Miyashiro Saitama 345-8501 Japan.
Coiled-coil protein carrier (CCPC) 140 is a rigid and anisotropically structured cationic coiled-coil artificial protein that has displayed up to a 1000 times higher level of cellular internalization activity than that of unstructured cell-penetrating peptides. Previous studies have demonstrated that CCPC 140's rigid and anisotropic structural properties and cationic surface properties are important for its superior cellular internalization activity. In this study, we investigated whether each physicochemical characteristic of CCPC 140 effectively contributed to activating the cellular internalization pathway.
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