Biomolecular condensates formed by designer minimalistic peptides.

Inspired by the role of intracellular liquid-liquid phase separation (LLPS) in formation of membraneless organelles, there is great interest in developing dynamic compartments formed by LLPS of intrinsically disordered proteins (IDPs) or short peptides. However, the molecular mechanisms underlying the formation of biomolecular condensates have not been fully elucidated, rendering on-demand design of synthetic condensates with tailored physico-chemical functionalities a significant challenge. To address this need, here we design a library of LLPS-promoting peptide building blocks composed of various assembly domains.

β-Cyanuryl Ribose, β-Barbituryl Ribose, and 6-Azauridine as Uridine Mimetics.

Uridine (U) mimetics are sought after as tools for biochemical and pharmacological studies. Previously, we have identified recognition patterns of U by proteins. Here, we targeted the characterization of uridine mimetics-cyanuryl-ribose (CR), barbituryl-ribose (BR), and 6-azauridine (AU)-with a view to identify analogs with potentially more binding interactions than U with target biomolecules.

Quantification of the Interaction of SmI with Substrates and Ligands.

The method developed and introduced here enables for the first time (to the authors' knowledge), a quantitative assessment of the interaction of SmI with substrates prior to the electron transfer stage. As a proof of concept, equilibrium constants for some model substrates including carbonyl compounds and aromatic nuclei are reported here. In addition, the first equilibrium constants with some common ligands were also determined.

Structural Elucidation of Three Novel Kaempferol -Glycosides that Are Involved in the Defense Response of Hybrid to .

is an ornamental flowering species that grows from a bulb and is highly susceptible to soft-rot disease caused by (Pc). Interspecific hybridization between and yielded hybrids with enhanced resistance to that pathogen. The hybrids displayed distinct phenolic-compound profiles with several peaks that were specifically heightened following Pc infection.

The biosynthetic pathway of the nonsugar, high-intensity sweetener mogroside V from Siraitia grosvenorii.

The consumption of sweeteners, natural as well as synthetic sugars, is implicated in an array of modern-day health problems. Therefore, natural nonsugar sweeteners are of increasing interest. We identify here the biosynthetic pathway of the sweet triterpenoid glycoside mogroside V, which has a sweetening strength of 250 times that of sucrose and is derived from mature fruit of luo-han-guo (Siraitia grosvenorii, monk fruit).

The Uptake and Assembly of Alkanes within a Porous Nanocapsule in Water: New Information about Hydrophobic Confinement.

In Nature, enzymes provide hydrophobic cavities and channels for sequestering small alkanes or long-chain alkyl groups from water. Similarly, the porous metal oxide capsule [{Mo(VI) 6 O21 (H2 O)6 }12 {(Mo(V) 2 O4 )30 (L)29 (H2 O)2 }](41-) (L=propionate ligand) features distinct domains for sequestering differently sized alkanes (as in Nature) as well as internal dimensions suitable for multi-alkane clustering. The ethyl tails of the 29 endohedrally coordinated ligands, L, form a spherical, hydrophobic "shell", while their methyl end groups generate a hydrophobic cavity with a diameter of 11 Å at the center of the capsule.

Novel crown-ether-methylenediphosphonotetrathioate hybrids as Zn(II) chelators.

Hybrids of methylenediphosphonotetrathioate and crown-ether (MDPT-CE) were synthesized forming 7-,8-,9-,10- and 13-membered rings. Both 7- and 13-membered ring-containing compounds were found to be highly stable to air-oxidation for at least four weeks. These hybrids bind Zn(II) by both MDPT and CE moieties, forming a 2 : 1 L : Zn(II) complex.

Studying the Conformation of a Silaffin-Derived Pentalysine Peptide Embedded in Bioinspired Silica using Solution and Dynamic Nuclear Polarization Magic-Angle Spinning NMR.

Smart materials are created in nature at interfaces between biomolecules and solid materials. The ability to probe the structure of functional peptides that engineer biogenic materials at this heterogeneous setting can be facilitated tremendously by use of DNP-enhanced solid-state NMR spectroscopy. This sensitive NMR technique allows simple and quick measurements, often without the need for isotope enrichment.

A [2 + 3] Reductive Cyclodimerization of Quinoline by SmI2.

Pyridine and its derivatives are rather difficult to reduce, and the products often undergo a very fast reoxidation to regain aromaticity. The reduction of quinoline by SmI2 results in an instantaneous [2 + 3] cyclization reaction, forming a bridged seven-membered ring within a polycyclic system.

EPR and NMR spectroscopies provide input on the coordination of Cu(I) and Ag(I) to a disordered methionine segment.

Methionine motifs are methionine-rich metal-binding segments found in many human, yeast, and bacterial proteins involved in the transportation of copper ion to other cellular pathways, and in protecting copper from oxidation. Methionine motifs are found to bind Ag(I) and Cu(I) ions. Proteins or peptides that can bind different metal ions should have the ability to differentiate between them, to be able to shuttle them to various pathways in the cell.

Spontaneous structural transition in phospholipid-inspired aromatic phosphopeptide nanostructures.

Phospholipid membranes could be considered a prime example of the ability of nature to produce complex yet ordered structures, by spontaneous and efficient self-assembly. Inspired by the unique properties and architecture of phospholipids, we designed simple amphiphilic decapeptides, intended to fold in the center of the peptide sequence, with a phosphorylated serine "head" located within a central turn segment, and two hydrophobic "tails". The molecular design also included the integration of the diphenylalanine motif, previously shown to facilitate self-assembly and increase nanostructure stability.

A chemical chaperone-based drug candidate is effective in a mouse model of amyotrophic lateral sclerosis (ALS).

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by the selective death of motor neurons and skeletal muscle atrophy. The majority of ALS cases are acquired spontaneously, with inherited disease accounting for only 10 % of all cases. Recent studies provide compelling evidence that aggregates of misfolded proteins underlie both types of ALS.

NMR studies of DNA microcapsules prepared using sonochemical methods.

DNA molecules were recently converted using ultrasonic irradiation into microcapsules that can trap hydrophobic molecules in aqueous solution. These DNA microcapsules are capable of penetrating prokaryotic and eukaryotic cells, delivering drugs and transferring genetic information e.g.

1,1-diamino-2,2-dinitroethylenes are always zwitterions.

The nitration of tetraiodoethylene (7) yields 1,1-diiodo-2,2-dinitroethylene (8). The latter reacts with alkylamines 9 or alkyldiamines 11 to give the corresponding acyclic 1,1-diamino-2,2-dinitroethylenes 10 or their cyclic analogs 12, respectively. On the basis of liquid and solid-state (13)C and (15)N NMR data, x-ray analysis and ab initio calculations, we suggest that the title compounds are always zwitterionic and that the C(A)-C(N) bond is not a true double bond.

Studies of Mg2+/Ca2+ complexes of naturally occurring dinucleotides: potentiometric titrations, NMR, and molecular dynamics.

Dinucleotides (Np(n)N'; N and N' are A, U, G, or C, n = 2-7) are naturally occurring physiologically active compounds. Despite the interest in dinucleotides, the composition of their complexes with metal ions as well as their conformations and species distribution in living systems are understudied. Therefore, we investigated a series of Mg(2+) and Ca(2+) complexes of Np(n)N's.

Bioassay for assessing cell stress in the vicinity of radio-frequency irradiating antennas.

The 24 h exposure of water plants (etiolated duckweed) to RF-EMF between 7.8 V m(-1) and 1.8 V m(-1), generated by AM 1.

Rac-dependent doubling of HeLa cell area and impairment of cell migration and cell cycle by compounds from Iris germanica.

Plants are an infinite source of bioactive compounds. We screened the Israeli flora for compounds that interfere with the organization of the actin cytoskeleton. We found an activity in lipidic extract from Iris germanica that was able to increase HeLa cell area and adhesion and augment the formation of actin stress fibers.

What is the conformation of physiologically-active dinucleoside polyphosphates in solution? Conformational analysis of free dinucleoside polyphosphates by NMR and molecular dynamics simulations.

Dinucleoside polyphosphates, or dinucleotides (Np(n)N'; N, N' = A, U, G, C; n = 2-7), are naturally occurring ubiquitous physiologically active compounds. Despite the interest in dinucleotides, and the relevance of their conformation to their biological function, the conformation of dinucleotides has been insufficiently studied. Therefore, here we performed conformational analysis of a series of Np(n)N' Na(+) salts (N = A, G, U, C; N' = A, G, U, C; n = 2-5) by various NMR techniques.

Oligonucleotides are potent antioxidants acting primarily through metal ion chelation.

We report on a rather unknown feature of oligonucleotides, namely, their potent antioxidant activity. Previously, we showed that nucleotides are potent antioxidants in Fe(II)/Cu(I/II)-H(2)O(2) systems. Here, we explored the potential of 2'-deoxyoligonucleotides as inhibitors of the Fe(II)/Cu(I/II)-induced *OH formation from H(2)O(2).

Induction of G2/M arrest and apoptosis by sesquiterpene lactones in human melanoma cell lines.

Malignant melanoma is a highly aggressive tumor which frequently resists chemotherapy, therefore, the search for new agents for its treatment is of great importance. In this study, we purified the sesquiterpene lactones (SLs), Tomentosin and Inuviscolide from Inula viscosa (Compositae) leaves and studied their anti-cancer potency against human melanoma cell lines in order to develop new agents for melanoma treatment. SLs inhibited the proliferation of three human melanoma cell lines: SK-28, 624 mel and 1363 mel in a dose-dependent manner.

Molecular recognition of adenosine deaminase: 15N NMR studies.

The elucidation of the molecular recognition of adenosine deaminase (ADA), the interpretation of the catalytic mechanism, and the design of novel inhibitors are based mostly on data obtained for the crystalline state of the enzyme. To obtain evidence for molecular recognition of the physiologically relevant soluble enzyme, we studied its interactions with the in situ formed inhibitor, 6-OH-purine riboside (HDPR), by 1D-15N- and 2D-(1H-15N)- NMR using the labeled primary inhibitor [15N4]-PR. We synthesized both [15N4]-PR and an [15N4]-HDPR model, from relatively inexpensive 15N sources.

A molecular mechanics approach to mapping the conformational space of diaryl and triarylphosphines.

A molecular mechanics force field has been developed which accurately reproduces experimental solid state structures and conformer interconversion barriers for a series of sterically congested diaryl and triaryl phosphines and some of their chalcogenide and Cr(CO)5 derivatives.