Quantifying Hydrogen-Bonding Interactions in the Self-Assembly of Photoresponsive Azobenzene Amphiphiles at the Air-Water Interface.

Amphiphilic azobenzene molecules offer ample scope to design functional supramolecular systems in an aqueous medium that can be controlled by light. Despite their widespread applications in photopharmacology and optoelectronics, the self-assembly pathways and energy landscapes of these systems are not well understood. Here, we report combined molecular dynamics (MD) simulation and surface manometry studies on a specially designed alkylated, meta-substituted azobenzene derivative to quantify the hydrogen-bonding interactions in the self-assembled monolayers of its photoisomers.

Extreme makeover: the incredible cell membrane adaptations of extremophiles to harsh environments.

The existence of life beyond Earth has long captivated humanity, and the study of extremophiles-organisms surviving and thriving in extreme environments-provides crucial insights into this possibility. Extremophiles overcome severe challenges such as enzyme inactivity, protein denaturation, and damage of the cell membrane by adopting several strategies. This feature article focuses on the molecular strategies extremophiles use to maintain the cell membrane's structure and fluidity under external stress.

Investigating the Influence of Photoswitchable Lipids on the Structure and Dynamics of Lipid Membranes: Fundamentals and Potential Applications.

In this work, we delve into the impact of photoisomerization of photoswitchable lipids (PSLs) on the membrane structure and dynamics at a molecular level. Through all-atom molecular dynamics simulations, we explore how UV irradiation-induced trans-to-cis isomerization of these lipids, particularly the azobenzene-derivatized phosphatidylcholine (AzoPC) lipid, influences the structure and dynamics of a simplified lipid membrane, mimicking those of bacteria across different temperatures. Our findings align with previous experimental observations regarding membrane properties and offer insights into localized effects and microscopic heterogeneity.

How do Photoswitchable Lipids Influence the Intercalation of Anticancer Drug in Lipid Membrane? Investigation using Molecular Dynamics Simulation.

Photoswitchable lipids, particularly azobenzene-derivatized phosphatidylcholine (azoPC) lipids, offer a unique mechanism for reversible modification of membrane properties upon exposure to ultraviolet (UV) radiation. Through all-atom molecular dynamics simulations, we explore how UV irradiation-induced trans-to-cis photoisomerization (TCPI) of AzoPC lipid influences the structure and dynamics of a lipid membrane, composed of dipalmitoylphosphatidylcholine (DPPC) and cholesterol with similar composition to that of the DOXIL®. Structural and dynamical analyses of two states of the membrane, 'dark' state (containing cis-azoPC lipid) and 'bright' state (containing 85 % cis-azoPC and 15 % trans-azoPC lipids) reveal that the TCPI reduces membrane packing density and increases diffusivity of lipids.

Unraveling the Molecular Mechanisms of Trehalose-Mediated Protection and Stabilization of Escherichia coli Lipid Membrane during Desiccation.

Trehalose, a disaccharide renowned for its ability to stabilize biomolecular architectures under strenuous conditions, finds extensive use in the cryopreservation of probiotics. A profound comprehension of its molecular-level interactions is of great significance. It is notable that current research in the realm of lipid-sugar interactions primarily employs single-component lipid bilayers, which are far from being representative of real cell membranes.

How Do Cyclopropane Fatty Acids Protect the Cell Membrane of in Cold Shock?

The cyclopropanation of unsaturated lipid acyl chains of some bacterial cell membranes is an important survival strategy to protect the same against drastic cooling. To elucidate the role of cyclopropane ring-containing lipids, we have simulated the lipid membrane of () and two modified membranes by replacing the cyclopropane rings with either single or double bonds at widely different temperatures. It has been observed that the cyclopropane rings provide more rigid kinks in the lipid acyl chain compared to the double bonds and therefore further reduce the packing density of the membrane and subsequently enhance the membrane fluidity at low temperatures.

Can Urea and Trimethylamine--oxide Prevent the Pressure-Induced Phase Transition of Lipid Membrane?

Organisms dwelling in ocean trenches are exposed to the high hydrostatic pressure of ocean water. Increasing pressure can alter the membrane packing density and fluidity and trigger the fluid-to-gel phase transition. To combat environmental stress, the organisms synthesize small polar solutes, which are known as osmolytes.

How Do Urea and Trimethylamine -Oxide Influence the Dehydration-Induced Phase Transition of a Lipid Membrane?

Living organisms are often exposed to extreme dehydration, which is detrimental to the structure and function of the cell membrane. The lipid membrane undergoes fluid-to-gel phase transition due to dehydration and thus loses fluidity and functionality. To protect the fluid phase of the bilayer these organisms adopt several strategies.

Effect of TMAO on the Structure and Phase Transition of Lipid Membranes: Potential Role of TMAO in Stabilizing Cell Membranes under Osmotic Stress.

Extremophiles adopt strategies to deal with different environmental stresses, some of which are severely damaging to their cell membrane. To combat high osmotic stress, deep-sea organisms synthesize osmolytes, small polar organic molecules, like trimethylamine--oxide (TMAO), and incorporate them in the cell. TMAO is known to protect cells from high osmotic or hydrostatic pressure.