Table_3_Transmembrane Peptides as Sensors of the Membrane Physical State.DOCX

<p>Cell membranes are commonly considered fundamental structures having multiple roles such as confinement, storage of lipids, sustain and control of membrane proteins. In spite of their importance, many aspects remain unclear. The number of lipid types is orders of magnitude larger than the number of amino acids, and this compositional complexity is not clearly embedded in any membrane model. A diffused hypothesis is that the large lipid palette permits to recruit and organize specific proteins controlling the formation of specialized lipid domains and the lateral pressure profile of the bilayer. Unfortunately, a satisfactory knowledge of lipid abundance remains utopian because of the technical difficulties in isolating definite membrane regions. More importantly, a theoretical framework where to fit the lipidomic data is still missing. In this work, we wish to utilize the amino acid sequence and frequency of the membrane proteins as bioinformatics sensors of cell bilayers. The use of an alignment-free method to find a correlation between the sequences of transmembrane portion of membrane proteins with the membrane physical state (MPS) suggested a new approach for the discovery of antimicrobial peptides.</p

Table_2_Transmembrane Peptides as Sensors of the Membrane Physical State.docx

<p>Cell membranes are commonly considered fundamental structures having multiple roles such as confinement, storage of lipids, sustain and control of membrane proteins. In spite of their importance, many aspects remain unclear. The number of lipid types is orders of magnitude larger than the number of amino acids, and this compositional complexity is not clearly embedded in any membrane model. A diffused hypothesis is that the large lipid palette permits to recruit and organize specific proteins controlling the formation of specialized lipid domains and the lateral pressure profile of the bilayer. Unfortunately, a satisfactory knowledge of lipid abundance remains utopian because of the technical difficulties in isolating definite membrane regions. More importantly, a theoretical framework where to fit the lipidomic data is still missing. In this work, we wish to utilize the amino acid sequence and frequency of the membrane proteins as bioinformatics sensors of cell bilayers. The use of an alignment-free method to find a correlation between the sequences of transmembrane portion of membrane proteins with the membrane physical state (MPS) suggested a new approach for the discovery of antimicrobial peptides.</p

On–Off Mechano-responsive Switching of ESIPT Luminescence in Polymorphic <i>N</i>‑Salicylidene-4-amino-2-methylbenzotriazole

We report the synthesis of a luminescent <i>N</i>-salicylidene aniline derivative, <i>N</i>-salicylidene-4-amino-2-methylbenzotriazole (<b>1</b>), and the study of its polymorphism and photophysical properties. Three phases showing yellow (<b>1-Y</b>), orange (<b>1-O</b>), and red (<b>1-R</b>) fluorescence have been isolated and characterized by thermal and single crystal X-ray analysis. The photoluminescence results from excited-state intramolecular proton transfer process and the quantum yield is strongly dependent on polymorphism (Φ_1‑Y = 0.87, Φ_1‑O = 0.11, Φ_1‑R = 0.028). The poorly emitting <b>1-R</b> can be easily prepared, converted to the bright <b>1-Y</b> by grinding, and reverted to <b>1-R</b> through melting and annealing, giving rise to a luminescence on–off mechano-responsive cycle. The different photophysical properties are explained with the variable π-overlap and molecular conformation changes in the three polymorphs, characterized by a very similar crystal packing. By DFT calculations, the absorption properties were explained as dependent on the torsion angle between the two planar portions of the molecule, which affects the equilibrium between enol and keto forms in the ground state