Search results for "hydrophilic"

The C-terminal Domains of Apoptotic BH3-only Proteins Mediate Their Insertion into Distinct Biological Membranes

2016

Changes in the equilibrium of pro- and anti-apoptotic members of the B-cell lymphoma-2 (Bcl-2) protein family in the mitochondrial outer membrane (MOM) induce structural changes that commit cells to apoptosis. Bcl-2 homology-3 (BH3)-only proteins participate in this process by either activating pro-apoptotic effectors or inhibiting anti-apoptotic components and by promoting MOM permeabilization. The association of BH3-only proteins with MOMs is necessary for the activation and amplification of death signals; however, the nature of this association remains controversial, as these proteins lack a canonical transmembrane sequence. Here we used an in vitro expression system to study the inserti…

Exploring Strategies for Labeling Viruses with Gold Nanoclusters through Non-equilibrium Molecular Dynamics Simulations.

2017

Biocompatible gold nanoclusters can be utilized as contrast agents in virus imaging. The labeling of viruses can be achieved noncovalently but site-specifically by linking the cluster to the hydrophobic pocket of a virus via a lipid-like pocket factor. We have estimated the binding affinities of three different pocket factors of echovirus 1 (EV1) in molecular dynamics simulations combined with non-equilibrium free-energy calculations. We have also studied the effects on binding affinities with a pocket factor linked to the Au102pMBA44 nanocluster in different protonation states. Although the absolute binding affinities are over-estimated for all the systems, the trend is in agreement with r…

Membrane insertion and topology of the translocon-associated protein (TRAP) gamma subunit

2017

Translocon-associated protein (TRAP) complex is intimately associated with the ER translocon for the insertion or translocation of newly synthesised proteins in eukaryotic cells. The TRAP complex is comprised of three single-spanning and one multiple-spanning subunits. We have investigated the membrane insertion and topology of the multiple-spanning TRAP-γ subunit by glycosylation mapping and green fluorescent protein fusions both in vitro and in cell cultures. Results demonstrate that TRAP-γ has four transmembrane (TM) segments, an Nt/Ct cytosolic orientation and that the less hydrophobic TM segment inserts efficiently into the membrane only in the cellular context of full-length protein.

Hidden complexity in membrane permeabilization behavior of antimicrobial polycations.

2021

A promising alternative to classical antibiotics are antimicrobial peptides and their synthetic mimics (smAMPs) that supposedly act directly on membranes. For a more successful design of smAMPs, we need to know how the type of interaction with the membrane determines the type of membrane perturbation. How this, in turn, transfers into selectivity and microbial killing activity is largely unknown. Here, we characterize the action of two smAMPs: MM:CO (a copolymer of hydrophobic cyclooctyl subunits and charged β-monomethyl-α-aminomethyl subunits) and the highly charged poly-NM (a homopolymer of α-aminomethyl subunits). By thorough characterization of vesicle leakage experiments, we elucidate …

Resistance to water and abrasion of a broad-spectrum sunscreen: a prospective, open-label study.

2015

PHEA-PLA biocompatible nanoparticles by technique of solvent evaporation from multiple emulsions

2015

Nanocarriers of amphiphilic polymeric materials represent versatile delivery systems for poorly water soluble drugs. In this work the technique of solvent evaporation from multiple emulsions was applied to produce nanovectors based on new amphiphilic copolymer, the α,β-poly(N-2-hydroxyethyl)-DL-aspartamide-polylactic acid (PHEA-PLA), purposely synthesized to be used in the controlled release of active molecules poorly soluble in water. To this aim an amphiphilic derivative of PHEA, a hydrophilic polymer, was synthesized by derivatization of the polymeric backbone with hydrophobic grafts of polylactic acid (PLA). The achieved copolymer was thus used to produce nanoparticles loaded with α toc…

Gold nanostar–polymer hybrids for siRNA delivery: Polymer design towards colloidal stability and in vitro studies on breast cancer cells

2017

To overcome the low bioavailability of siRNA (small interfering RNA) and to improve their transfection efficiency, the use of non-viral delivery carriers is today a feasible approach to transform the discovery of these incredibly potent and versatile drugs into clinical practice. Polymer-modified gold nanoconstructs (AuNCs) are currently viewed as efficient and safe intracellular delivery carriers for siRNA, as they have the possibility to conjugate the ability to stably entrap and deliver siRNAs inside cells with the advantages of gold nanoparticles, which can act as theranostic agents and radiotherapy enhancers through laser-induced hyperthermia. In this study, AuNCs were prepared by coat…

Polymeric Nanoparticles with Neglectable Protein Corona

2020

Small : nano micro 16(18), 1907574 (2020). doi:10.1002/smll.201907574

Performance of amines as silanol suppressors in reversed-phase liquid chromatography

2016

In reversed-phase liquid chromatography, cationic basic compounds yield broad and asymmetrical peaks, as a result of their ionic interaction with the anionic free silanol groups present in the silica-based stationary phases (commonly derivatised with C18 groups). A simple way to improve the peak shape is the addition to the hydro-organic mobile phase of a reagent (usually called additive) with cationic character. This associates with the stationary phase to prevent the access of analytes to the free silanol groups. Cationic additives may interact electrostatically with the anionic silanols. The hydrophobic region of the additive may also associate with the alkyl chains bound to the stationa…

Lentes de contato corneoesclerais adaptadas em córneas irregulares após cirurgia LASIK

2018

ABSTRACT Purpose: We aimed to describe the outcomes of corneoscleral contact lens fitting with multi-aspherical geometry designs in patients with irregular corneas after laser-assisted in situ keratomileusis (LASIK). Methods: This was a retrospective series of 18 patients (age, 26-38 years) selected from an eye clinic database. Participants were required to have unsatisfactory visual acuity with their current contact lenses or spectacles after LASIK for myopia correction. All patients were fitted with corneoscleral contact lenses designed to correct corneal surface irregularities. A diagnostic trial set was used for fitting, and assessments were performed according to a standardized methodo…