Israel Journal of Chemistry最新文献

The cover image shows amphiphilic calixarenes embedded in a phospholipid bilayer membrane. Anionic calixarenes facilitate counterion-mediated transport of positively charged peptides across said membranes highlighting the utility of amphiphilic calixarenes for peptide transport into liposome and for direct cytosolic delivery of charged molecules into cells, which still is a significant problem in the fields of biology and medicine. [the image refers to the article “Anionic Calixarenes in Biomembrane Transport of Peptides” by Justin Neumann and Andreas Hennig.]

We are excited to introduce this special issue of the Israel Journal of Chemistry on Synthetic Host Molecules to celebrate the remarkable progress of the field. Featuring eleven scientific reviews and research articles from leading scientists worldwide, the special issue on synthetic host molecules explores the latest advances in some of the host systems developed during the last decades.

This issue also commemorates the milestone of the Joint Conference on Calixarenes and Cucurbiturils (JCCC 2023), which merged the 17^th International Conference on Calixarenes (Calix 2023) and the 7^th International Conference on Cucurbiturils (ICCB 2023) in Tel Aviv in July 2023. This event offered a unique opportunity to unite experts from both subfields, fostering dialogues and collaborations. It was a particularly significant gathering after a hiatus caused by the COVID-19 pandemic, which had disrupted the individual meetings of each conference.

The field of synthetic host molecules originated in the ′60s when Charles J. Pedersen reported the first examples of crown ethers and their remarkable capabilities to bind alkali metal ions according to their cavity size and the metal radii. Shortly after, Jean-Marie Lehn developed cryptands, bicyclic crown ether compounds with higher selectivity. In 1979, Donald Cram introduced spherands, the first examples of synthetic hosts with complete preorganization, significantly reducing the energetic penalty associated with the reorganization and desolvation of crown ethers and cryptands. These groundbreaking contributions earned Pedersen, Lehn, and Cram the Nobel Prize in Chemistry in 1987, officially establishing the field of Supramolecular Chemistry.

Over the last four decades, the field has accelerated rapidly, developing numerous new classes of synthetic host molecules. These systems have evolved from molecules capable of binding organic and inorganic ions to advanced hosts with unique structural, catalytic, optoelectronic, magnetic, and transmembrane transport properties. They can selectively bind myriad organic and bioorganic molecules in diverse media, including water. As a result, these highly functional host molecules have found applications in various fields, including medicine, biotechnology, catalysis, chemical separation, data storage, polymer science, and nanotechnology. This progress has been made possible through interdisciplinary research that merges concepts from synthetic chemistry, physical organic chemistry, computational chemistry, biophysics, and state-of-the-art analytical techniques.

Prof. Pablo Ballester and Dr. Gemma Aragay present an authoritative review on water-soluble aryl- and aryl-extended calix[4]pyrroles. They highlight their achievements over the last two decades to incorporate water-solubilizing groups, enhance the hydrophobic aromatic cavity, and reduce the conformational flexibility of calix[4]pyrroles, resulting in o

Chemical Biology of Nucleic Acid Modifications II Issue editor: Chun-Xiao Song, Guifang Jia, Seraphine Wegner, and Chengqi Yi. The cover picture highlights Chuan He's wide-ranging research contributions across chemical biology, nucleic acid chemistry, biology, and epigenetics. His work focused on understanding DNA and RNA modifications in gene regulation. His groundbreaking discovery of reversible RNA modification revealed a new mode of gene regulation by RNA alongside DNA — and protein-based epigenetic mechanisms, leading to the emergence of the epitranscriptomics field.

N⁶-methyladenosine (m⁶A), as the most abundant and well-studied RNA modification, can be reversibly added or removed by m⁶A methyltransferase and demethylase. The further molecular and biological function of m⁶A is achieved by the recognition of its binding protein. m⁶A functions in the diverse progress of RNA processing, including transcription regulation, splicing, nuclear export, stability, and translation, to regulate the fate of cells. Although been extensively studied in various animal cell systems, research on m⁶A's regulatory functions in plant cells lags. In recent years, with a deepening understanding of the functions of m⁶A and the development of various sequencing technologies, researches on m⁶A in plant cells have gradually increased. In this review, we focused on discussing the molecular functions of m⁶A in the nucleus and cytoplasm, aiming to elucidate the specific molecular mechanisms by which m⁶A regulates the fate of RNAs in plants. Finally, we provide some perspectives on future investigations of the detailed molecular mechanism of m⁶A-mediated regulation in plants, which might provide insights into future strategies for achieving multiple growth regulatory processes in crops.

Nucleic acid modifications play essential roles in diverse biological processes, ranging from gene expression regulation to stress response. While traditional research focused on common modifications like methylation, recent discoveries are unveiling a wide range of rare modifications with potentially crucial functions. However, accurately detecting and mapping these modifications pose significant challenges due to their low abundance and diverse chemical properties. This article summarizes the recent discoveries of rare DNA and RNA modifications across various organisms, highlighting their potential biological significance. Furthermore, it critically evaluates the limitations of current mapping techniques, including potential sources of false positives and negatives. Finally, the article discusses emerging strategies for overcoming these challenges and future opportunities in the field of rare nucleic acid modification detection.

Biomembranes function as hydrophobic barriers for hydrophilic substances enabling compartmentalization in biological systems. This poses, however, a problem for the targeted introduction of cargo into cells. The result is a high demand for delivery pathways into cells with the goal to investigate biological processes or to treat diseases by improved delivery. Polycationic cell-penetrating peptides (CPPs) are interesting as they can cross cell membranes and transport attached cargos directly into the cytosol. Their efficiency can be improved by anionic amphiphilic counterion activators, which bind to the CPPs to form charge-neutralized counterion-CPP complexes with sufficient hydrophobicity to cross the lipid bilayer membrane. This review summarizes recent results, which establish amphiphilic calixarenes as a new class of biocompatible and non-cytotoxic counterion activators with very high transport activities at nanomolar concentrations. We also include a brief summary of fluorescence-based assays with large unilamellar vesicles (LUVs) to investigate counterion-activated transport. Current methods use liposome-encapsulated, supramolecular host-dye reporter pairs including calixarenes, which provide new mechanistic insights and enable rapid in vitro identification of suitable activators. Taken together, amphiphilic calixarenes are currently emerging as prime candidates for counterion activation of membrane transport, which are highly modifiable and can be specifically tailored towards different cargoes and membrane types.