Search results for "hydrophobic"
showing 10 items of 332 documents
Interaction of G protein coupled receptors and cholesterol
2016
G protein coupled receptors (GPCRs) form the largest receptor superfamily in eukaryotic cells. Owing to their seven transmembrane helices, large parts of these proteins are embedded in the cholesterol-rich plasma membrane bilayer. Thus, GPCRs are always in proximity to cholesterol. Some of them are functionally dependent on the specific presence of cholesterol. Over the last years, enormous progress on receptor structures has been achieved. While lipophilic ligands other than cholesterol have been shown to bind either inside the helix bundle or at the receptor-lipid interface, the binding site of cholesterol was either a single transmembrane helix or a groove between two or more transmembra…
Viral Bcl2s' transmembrane domain interact with host Bcl2 proteins to control cellular apoptosis
2020
© The Author(s) 2020.
The Crystal Structure of Gurmarin, a Sweet Taste–Suppressing Protein: Identification of the Amino Acid Residues Essential for Inhibition
2018
International audience; Gurmarin is a highly specific sweet-taste suppressing protein in rodents that is isolated from the Indian plant Gymnemasylvestre. Gurmarin consists of 35 amino acid residues containing three intramolecular disulfide bridges that form a cystine knot. Here, we report the crystal structure of gurmarin at a 1.45 Å resolution and compare it with previously reported NMR solution structures. The atomic structure at this resolution allowed us to identify a very flexible region consisting of hydrophobic residues. Some of these amino acid residues had been identified as a putative binding site for the rat sweet taste receptor in a previous study. By combining alanine-scanning …
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.
2021
The hydrophobic tails of aliphatic primary alcohols do insert into the hydrophobic core of a lipid bilayer. Thereby, they disrupt hydrophobic interactions between the lipid molecules, resulting in a decreased lipid order, i.e., an increased membrane fluidity. While aromatic alcohols, such as 2-phenylethanol, also insert into lipid bilayers and disturb the membrane organization, the impact of aromatic alcohols on the structure of biological membranes, as well as the potential physiological implication of membrane incorporation has only been studied to a limited extent. Although diverse targets are discussed to be causing the bacteriostatic and bactericidal activity of 2-phenylethanol, it is …
The Role of Hydrophobic Mismatch on Transmembrane Helix Dimerization in Living Cells
2019
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 …