In the field of self-assembly,
the quest for gaining control over
the supramolecular architecture without affecting the functionality
of the individual molecular building blocks is intrinsically challenging.
By using a combination of synthetic chemistry, cryogenic transmission
electron microscopy, optical absorption measurements, and exciton
theory, we demonstrate that halogen exchange in carbocyanine dye molecules
allows for fine-tuning the diameter of the self-assembled nanotubes
formed by these molecules, while hardly affecting the molecular packing
determined by hydrophobic/hydrophilic interactions. Our findings open
a unique way to study size effects on the optical properties and exciton
dynamics of self-assembled systems under well-controlled conditions.
The rapid development of antimicrobial resistance is threatening mankind to such an extent that the World Health Organization expects more deaths from infections than from cancer in 2050 if current trends continue. To avoid this scenario, new classes of anti-infectives must urgently be developed. Antibiotics with new modes of action are needed, but other concepts are also currently being pursued. Targeting bacterial virulence as a means of blocking pathogenicity is a promising new strategy for disarming pathogens. Furthermore, it is believed that this new approach is less susceptible towards resistance development. In this review, recent examples of anti-infective compounds acting on several types of bacterial targets, e.g., adhesins, toxins and bacterial communication, are described.
SignificanceEscherichia coli has been engineered toward an archaebacterium with an unprecedented high level of archaeal ether phospholipids. The obtained cells stably maintain a mixed heterochiral membrane. This finding challenges theories that assume that intrinsic instability of mixed membranes led to the “lipid divide” and the subsequent differentiation of bacteria and archaea. Furthermore, this study paves the way for future membrane engineering of industrial production organisms with improved robustness.
The alkylation of arylamines using stoichiometric amounts of aliphatic and benzylic alcohols in the presence of tBuOK was carried out at 55 °C using a low catalyst loading of [Ru(cod)Cl2]n/PTA (1,3,5‐triaza‐7‐phosphaadamantane). The overall borrowing‐hydrogen process does not require a controlled nitrogen atmosphere, and it could also be carried out at room temperature using higher loading of base. A wide range of substrates can be used in this transformation, and it has a good tolerance of different substituents. This catalytic system proved also to be efficient for other hydrogen‐transfer reactions such as a tandem oxidation/C–C coupling between 1‐phenylethanol and primary alcohols.
Phenols can be efficiently reduced by sodium formate and Pd/C as the catalyst in water and in the presence of amines to give the corresponding cyclohexylamines. This reaction works at rt for 12 h or at 60 °C under microwave dielectric heating for 20 min. With the exception of aniline, primary, secondary amines, amino alcohols, and even amino acids can be used as nucleophiles. The reductive process is based on a sustainable hydrogen source and a catalyst that can be efficiently recovered and reused. The protocol was developed into a continuous-flow production of cyclohexylamines in gram scale achieving very efficient preliminary results (TON 32.7 and TOF 5.45 h(-1)).
Palladium-catalyzed oxidation can single out the secondary hydroxyl group at C3 in glucose, circumventing the more readily accessible hydroxyl at C6 and the more reactive anomeric hydroxyl. Oxidation followed by reduction results in either allose or allitol, each a rare sugar that is important in biotechnology. Also, N-acetylglucosamine is selectively oxidized at C3. These results demonstrate that glucose and N-acetylglucosamine, the most readily available chiral building blocks, can be versatile substrates in homogeneous catalysis.
The key role of RNA-binding proteins (RBPs) in regulating post-transcriptional processes and their involvement in several pathologies (i.e., cancer and neurodegeneration) have highlighted their potential as therapeutic targets. In this scenario, Embryonic Lethal Abnormal Vision (ELAV) or Hu proteins and their complexes with target mRNAs have been gaining growing attention. Compounds able to modulate the complex stability could constitute an innovative pharmacological strategy for the treatment of numerous diseases. Nevertheless, medicinal-chemistry efforts aimed at developing such compounds are still at an early stage. As part of our ongoing research in this field, we hereby present the rational design and synthesis of structurally novel HuR ligands, potentially acting as HuR−RNA interferers. The following assessment of the structural features of their interaction with HuR, combining saturation-transfer difference NMR and in silico studies, provides a guide for further research on the development of new effective interfering compounds of the HuR−RNA complex.
Kinetic target-guided synthesis represents an efficient hit-identification strategy,i nw hich the protein assembles its own inhibitors from ap oolo fc omplementary building blocks via an irreversible reaction. Herein, we pioneered an in situ Ugi reactionf or the identification of novel inhibitors of am odel enzyme and binders for an important drug target, namely,t he aspartic protease endothiapepsina nd the bacterial b-sliding clamp DnaN, respectively.H ighly sensitive mass-spectrometry methods enabledm onitoring of the protein-templated reaction of four complementaryr eaction partners, which occurredi nabackground-free manner for endothiapepsin or with ac lear amplification of two binders in the presence of DnaN. TheU gi products we identified show low micromolar activity on endothiapepsin or moderate affinity for the b-sliding clamp. We succeeded in expanding the portfolioo fc hemical reactions and biological targets and demonstrated the efficiency and sensitivity of this approach,which can find application on any drug target.
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