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Evgeniy S Salnikov, Jesus Raya, Marta De Zotti, Ekaterina Zaitseva, Cristina Peggion, Gema Ballano, Claudio Toniolo, Jan Raap, Burkhard Bechinger
Alamethicins (ALMs) are antimicrobial peptides of fungal origin. Their sequences are rich in hydrophobic amino acids and strongly interact with lipid membranes, where they cause a well-defined increase in conductivity. Therefore, the peptides are thought to form transmembrane helical bundles in which the more hydrophilic residues line a water-filled pore. Whereas the peptide has been well characterized in terms of secondary structure, membrane topology, and interactions, much fewer data are available regarding the quaternary arrangement of the helices within lipid bilayers...
December 6, 2016: Biophysical Journal
Dongsheng Wang, Manfred Wagner, Andrew Saydjari, Julius Mueller, Svenja Winzen, Hans-Jürgen Butt, Si Wu
We synthesized a novel green-light-responsive tetra-ortho-isopropoxy-substituted azobenzene (ipAzo). Cis ipAzo forms a strong host-guest complex with γ-cyclodextrin (γ-CD) while trans ipAzo binds weakly. This new photoresponsive host-guest interaction is reverse to the well-known azobenzene (Azo)/α-cyclodextrin (α-CD) complex, which is strong only between trans Azo and α-CD. By combining the UV-light-responsive Azo/α-CD and green-light-responsive ipAzo/γ-CD host-guest complexes, a photoresponsive orthogonal supramolecular system is developed...
December 7, 2016: Chemistry: a European Journal
Larissa K S von Krbek, Andreas J Achazi, Stefan Schoder, Marius Gaedke, Tobias Biberger, Beate Paulus, Christoph A Schalley
Rigidity and preorganisation are believed to be required for high affinity in multiply bonded supramolecular complexes as they help reducing the entropic penalty of the binding event. This comes at the price that such rigid complexes are sensitive to small geometric mismatches. In marked contrast, nature uses more flexible building blocks. Thus, one might consider putting the rigidity-high affinity notion to the test. Multivalent crown/ammonium complexes are ideal for this purpose as the monovalent interaction is well understood...
December 7, 2016: Chemistry: a European Journal
Dmytro Bykov, Thomas Kjaergaard
We report porting of the Divide-Expand-Consolidate Resolution of the Identity second-order Møller-Plesset perturbation (DEC-RI-MP2) method to the graphic processing units (GPUs) using OpenACC compiler directives. It is shown that the OpenACC compiler directives implementation efficiently accelerates the rate-determining step of the DEC-RI-MP2 method with minor implementation effort. Moreover, the GPU acceleration results in a better load balance and thus in an overall scaling improvement of the DEC algorithm...
December 7, 2016: Journal of Computational Chemistry
A K Gulevskvy, N V Repin, I I Schenvavsky
BACKGROUND: The antecedence of impairment of plasmatic membrane structure and functions forms the basis of the dominative concept about mechanisms of cell cryoinjuries. A role of alterations of hemoglobin supramolecular structure in erythrocytes remains unclear. OBJECTIVE: Comparison of continuity of membranes of native erythrocytes and resealed ghosts after freeze-thawing with a cryoprotectant at a low concentration (4%). MATERIALS AND METHODS: Cryoresistance of native erythrocytes and resealed ghosts with and without low concentrations of cryoprotectants (4% glycerol) was compared according to egress of the following markers: hemoglobin, 14С-sucrose and K+ as well as by scanning electron microscopy...
September 2016: Cryo Letters
David C Milan, Maximilian Krempe, Ali K Ismael, Levon D Movsisyan, Michael Franz, Iain Grace, Richard J Brooke, Walther Schwarzacher, Simon J Higgins, Harry L Anderson, Colin J Lambert, Rik R Tykwinski, Richard J Nichols
Oligoynes are archetypical molecular wires due to their 1-D chain of conjugated carbon atoms and ability to transmit charge over long distances by coherent tunneling. However, the stability of the oligoyne can be an issue. Here we address this problem by two stabilization methods, namely sterically shielding endgroups, and rotaxination to produce an insulated molecular wire. We demonstrate the threading of a hexayne within a macrocycle to form a rotaxane and report measurements of the electrical conductance of this single supramolecular assembly within an STM break junction...
December 7, 2016: Nanoscale
Mukesh Sharma, Plaban Jyoti Sarma, Manash Jyoti Goswami, Kusum K Bania
Metallogel of iron-carboxylates was obtained from trans-1,2-cyclohexanedicarboxylic acid in dimethylformamide (DMF) at basic condition. Spectroscopic and SEM morphology study of the iron-metallogel revealed that the iron complex with dicarboxylic acid was linked together via carboxylates and led to a supramolecular helical like architecture. The synthesized metallogel served as an excellent template for in-situ reduction of silver ion to silver particles micro to nano scale range. Variation of AgNO3 concentration shepherd to change the morphology of the Ag-particles...
November 20, 2016: Journal of Colloid and Interface Science
A Six, A Bocheux, F Charra, F Mathevet, D Kreher, A-J Attias
Here we report the synthesis and characterization of a series of new phenylene-vinylene tectons. The study by scanning tunneling microscopy of their supramolecular self-assembly at the interface between a phenyloctane solution and highly oriented pyrolytic graphite  demonstrates that variation of concentration and length of alkyl chains led to the formation of different networks, a compact one and a nanoporous one, with a fine control of the lattice parameters. The study of guest-host properties of the nanoporous network revealed a selectivity toward guest compounds according to their shape and size...
December 6, 2016: Nanotechnology
Yingjie Liu, Suqian Ma, Bin Xu, Wenjing Tian
Aggregation-induced emission (AIE) provides a new way of achieving highly efficient luminescent materials. In this contribution, the self-assembly behavior, molecular stacking structure and photophysical properties of two polymorphs of a supramolecular co-crystal (C1 and C2) are investigated. The block-like crystal C1, packed in segregated stacking with strong π-π interactions between the H and G molecules, shows weak green emission with a low efficiency (ΦF) of 2%. In comparison, the needle-like crystal C2, packed in segregated stacking with no obviously strong intermolecular interactions, shows bright yellow emission...
December 6, 2016: Faraday Discussions
N V Roik, L A Belyakova
Silica carriers equipped with molecular and supramolecular pH-sensitive nanovalves were designed by combination of sol-gel synthesis and selective postsynthetic modification. Mesoporous structure of synthesized materials was characterized by low-temperature nitrogen adsorption-desorption, small-angle X-ray diffraction and transmission electron microscopy. Chemical immobilization of N-[N'-(N'-phenyl)-2-aminophenyl]aminoalkyl groups was confirmed by IR spectral and chemical analyses of surface layer. Loading and release behaviour of synthesized drug carriers was studied in phosphate buffer solutions with pH 5...
December 6, 2016: Interface Focus
Chung Yen Ang, Si Yu Tan, Cathleen Teh, Jia Min Lee, Mun Fei Eddy Wong, Qiuyu Qu, Li Qing Poh, Menghuan Li, Yuanyuan Zhang, Vladimir Korzh, Yanli Zhao
Responsive nanomaterials have emerged as promising candidates as drug delivery vehicles in order to address biomedical diseases such as cancer. In this work, polymer-based responsive nanoparticles prepared by a supramolecular approach are loaded with doxorubicin (DOX) for the cancer therapy. The nanoparticles contain disulfide bonds within the polymer network, allowing the release of the DOX payload in a reducing environment within the endoplasm of cancer cells. In addition, the loaded drug can also be released under acidic environment...
December 5, 2016: Small
Chih-Chia Cheng, Mei-Chih Liang, Zhi-Sheng Liao, Jyun-Jie Huang, Duu-Jong Lee
Simple construction and manipulation of low-molecular-weight supramolecular nanogels, based on the introduction of multiple hydrogen bonding interactions, with the desired physical properties to achieve effective and safe delivery of drugs for cancer therapy remain highly challenging. Herein, a novel supramolecular oligomer cytosine (Cy)-polypropylene glycol containing self-complementary multiple hydrogen-bonded Cy moieties is developed, which undergoes spontaneous self-assembly to form nanosized particles in an aqueous environment...
December 5, 2016: Macromolecular Bioscience
Chun Li Liu, Qiu Ying Huang, Xiang Ru Meng
The synthesis of coordination polymers or metal-organic frameworks (MOFs) has attracted considerable interest owing to the interesting structures and potential applications of these compounds. It is still a challenge to predict the exact structures and compositions of the final products. A new one-dimensional coordination polymer, catena-poly[[[bis{1-[(1H-benzimidazol-2-yl)methyl]-1H-tetrazole-κN(3)}zinc(II)]-μ-hexane-1,6-dicarboxylato-κ(4)O(1),O(1'):O(6),O(6')] monohydrate], {[Zn(C6H8O4)(C9H8N6)2]·H2O}n, has been synthesized by the reaction of Zn(Ac)2 (Ac is acetate) with 1-[(1H-benzimidazol-2-yl)methyl]-1H-tetrazole (bimt) and adipic acid (H2adi) at room temperature...
December 1, 2016: Acta Crystallographica. Section C, Structural Chemistry
Pattiya Krinchampa, Kittipong Chainok, Siriporn Phengthaisong, Sujittra Youngme, Filip Kielar, Nanthawat Wannarit
One of most interesting systems of coordination polymers constructed from the first-row transition metals is the porous Zn(II) coordination polymer system, but the numbers of such polymers containing N-donor linkers are still limited. The title double-chain-like Zn(II) coordination polymer, [Ag2Zn(CN)4(C10H10N2)2]n, presents a one-dimensional linear coordination polymer structure in which Zn(II) ions are linked by bridging anionic dicyanidoargentate(I) units along the crystallographic b axis and each Zn(II) ion is additionally coordinated by a terminal dicyanidoargentate(I) unit and two terminal 1-benzyl-1H-imidazole (BZI) ligands, giving a five-coordinated Zn(II) ion...
December 1, 2016: Acta Crystallographica. Section C, Structural Chemistry
Sevim Hamamci Alisir, Necmi Dege
Ag(I)-containing coordination complexes have attracted attention because of their photoluminescence properties and antimicrobial activities and, in principle, these properties depend on the nature of the structural topologies. A novel two-dimensional silver(I) complex with the anti-inflammatory diclofenac molecule, namely bis{μ-2-[2-(2,6-dichloroanilino)phenyl]acetato-κ(3)O,O':O}bis(μ-2,5-dimethylpyrazine-κ(2)N:N')silver(I), [Ag2(C14H10Cl2NO2)2(C6H8N2)]n, (I), has been synthesized and characterized by single-crystal X-ray diffraction, revealing that the Ag(I) ions are chelated by the carboxylate groups of the anionic 2-[2-(2,6-dichloroanilino)phenyl]acetate (dicl) ligand in a μ3-η(1):η(2) coordination mode...
December 1, 2016: Acta Crystallographica. Section C, Structural Chemistry
Gan Yin Yuan, Lei Zhang, Meng Jie Wang, Kou Lin Zhang
Much attention has been paid by chemists to the construction of supramolecular coordination compounds based on the multifunctional ligand 5-sulfosalicylic acid (H3SSA) due to the structural and biological interest of these compounds. However, no coordination compounds have been reported for the multifunctional amino-substituted sulfobenzoate ligand 2-amino-5-sulfobenzoic acid (H2asba). We expected that H2asba could be a suitable building block for the assembly of supramolecular networks due to its interesting structural characteristics...
December 1, 2016: Acta Crystallographica. Section C, Structural Chemistry
Juan Granifo, Beatriz Arévalo, Rubén Gaviño, Sebastián Suárez, Ricardo Baggio
4'-Substituted derivatives of 2,2':6',2''-terpyridine with N-containing heteroaromatic substituents, such as pyridyl groups, might be able to coordinate metal centres through the extra N-donor atom, in addition to the chelating terpyridine N atoms. The incorporation of these peripheral N-donor sites would also allow for the diversification of the types of noncovalent interactions present, such as hydrogen bonding and π-π stacking. The title compound, C24H16N4, consists of a 2,2':6',2''-terpyridine nucleus (tpy), with a pendant isoquinoline group (isq) bound at the central pyridine (py) ring...
December 1, 2016: Acta Crystallographica. Section C, Structural Chemistry
O Domarco, D Lötsch, J Schreiber, C Dinhof, S Van Schoonhoven, M D García, C Peinador, B K Keppler, W Berger, A Terenzi
Supramolecular Pt(ii) quadrangular boxes bind native and G-quadruplex DNA motifs in a size-dependent fashion. Three Pt molecular squares of distinct size show biological activity against cancer cells and heavily influence the expression of genes known to form G-quadruplexes in their promoter regions. The smallest Pt-box displays less activity but more selectivity for a quadruplex formed in the c-Kit gene.
December 5, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Shan-Shan Xue, Cai-Ping Tan, Mu-He Chen, Jian-Jun Cao, Dong-Yang Zhang, Rui-Rong Ye, Liang-Nian Ji, Zong-Wan Mao
We report here a supramolecular strategy to assemble a cyclodextrin-functionalized anticancer Ru(ii) complex with an adamantane-appended tumor-targeting peptide into discrete and stable phosphorescent nanostructures that can induce cell death in integrin αvβ3-rich tumor cells with high selectivity. This strategy presents new opportunities for the construction of tumor-targeting metallo-anticancer therapeutics.
December 5, 2016: Chemical Communications: Chem Comm
Francisco Fernandez-Palacio, Mikko Poutanen, Marco Saccone, Antti Siiskonen, Giancarlo Terraneo, Giuseppe Resnati, Olli Ikkala, Pierangelo Metrangolo, Arri Priimagi
Here, we present a new family of light-responsive, fluorinated supramolecular liquid crystals (LCs) showing efficient and reversible light-induced LC-to-isotropic phase transitions. Our materials design is based on fluorinated azobenzenes, where the fluorination serves to strengthen the noncovalent interaction with bond-accepting stilbazole molecules, and increase the lifetime of the cis-form of the azobenzene units. The halogen-bonded LCs were characterized by means of X-ray diffraction, hot-stage polarized optical microscopy, and differential scanning calorimetry...
November 22, 2016: Chemistry of Materials: a Publication of the American Chemical Society
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