How Do Glycine-Induced Bent Structures Influence Hierarchical Nanostructuring and Suprastructural Handedness in Short Peptide Assembly?

Despite the multiple roles of flexible and achiral Gly in regulating protein architectures and functions, its high flexibility is seldom exploited as a structural modulator in the design of self-assembling peptides. By using minimalistic peptide sequences, the effects of Gly insertions are investigated on the molecular conformation and the supramolecular morphology, focusing on Gly-induced bent structures and their impact on self-assembled nanostructures and handedness. Different backbone bending degrees are generated by varying Gly position, which in turn resulted in distinct hydrogen bonding modes and residue shifting upon dimerization, eventually leading to β-sheets and nanofibrils with opposite handedness.

Degradation of anthracene and phenanthrene by strain Streptomyces sp. M-1 and its application in the treatment of PAHs-contaminated water.

Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants with mutagenicity, carcinogenicity and teratogenicity, widely distributed in the environment. Effective biodegradation of PAHs is highly required, especially in wastewater. An efficient PAHs degrading strain Streptomyces sp.

Preparation and characterization of the octenyl succinic anhydride (OSA) modified sphingan WL gum as novel biopolymeric surfactants.

Combining polymer and surfactant in one agent namely polymeric surfactants with both high viscosity and surface activity has become a viable alternative for the traditional enhanced oil recovery (EOR) processes. With the purpose of developing new polymeric surfactants, the biopolymer flooding agent sphingan WL gum was modified by octenyl succinic anhydride (OSA) through the esterification reaction. The effects of molecular weight (MW) of WL and the OSA: WL ratio on the properties of the products were investigated.

Tunable Chiroptical Activity in Branched Ag@Au Nanoparticles with Molecular Chirality and Geometric Chirality.

Chiral plasmonic nanomaterials have attracted significant awareness due to their applications in chiral catalysis, biosensing, photonics, and separation. Constructing plasmonic core-shell nanomaterials with geometric chirality and desirable optical chirality is a crucial yet challenging task for extending the range of chiral plasmonic nanomaterials. Here, a two-step method is reported for the synthesis of Gold (Au) branches wrapped silver (Ag) nanocubes (L/DBAg@Au) with strong and tunable circular dichroism (CD) signals under the regulation of L/D-cysteine (L/D-Cys).

Controlling lamination and directional growth of β-sheets via hydrophobic interactions: The strategies and insights.

The self-assembling morphologies of proteins, nucleic acids, and peptides are well correlated with their functioning in biological systems. In spite of extensive studies for the morphologies regulating, the directional control of the assembly morphology structure for the peptides still remains challenging. Here, the directional structure control of a bola-like peptide Ac-KIIF-CONH (KIIF) was realized by introducing different amount of acetonitrile to the system.

Chiral inversion induced by aromatic interactions in short peptide assembly.

Although hydrophobic interactions provide the main driving force for initial peptide aggregation, their role in regulating suprastructure handedness of higher-order architectures remains largely unknown. We here interrogate the effects of hydrophobic amino acids on handedness at various assembly stages of peptide amphiphiles. Our studies reveal that relative to aliphatic side chains, aromatic side chains set the twisting directions of single β-strands due to their strong steric repulsion to the backbone, and upon packing into multi-stranded β-sheets, the side-chain aromatic interactions between strands form the aromatic ladders with a directional preference.

Amino acid-induced synthesis of chiral AgAuPt nanoparticles with branched structure for circularly polarized enantioselective photoelectrocatalytic water splitting.

Chiral Plasmonic nanomaterials have gradually illustrated intriguing circularly polarized light (CPL)-dependent properties in photocatalysis due to their unique chiral optical activity. However, the connection between chiral characteristics and catalytic performance of these materials in cooperative systems is rarely reported and remains a challenge task. In this work, branched AgAuPt nanoparticles induced by L/d-cysteine (Cys) with strong and perfectly symmetric circular dichroism (CD) signals are synthesized.

Glutathione-mediated copper sulfide nanoplatforms with morphological and vacancy-dependent photothermal catalytic activity for multi-model tannic acid assays.

Interface engineering and vacancy engineering play an important role in the surface and electronic structure of nanomaterials. The combination of the two provides a feasible way for the development of efficient photocatalytic materials. Here, we use glutathione (GSH) as a coordination molecule to design a series of CuS nanomaterials (CuS-GSH) rich in sulfur vacancies using a simple ultrasonic-assisted method.

The effects of different impeller combinations in the Sphingan WL gum fermentation process.

The fermentation of the high-viscosity polysaccharide WL gum has always been associated with poor mass transfer. Appropriate impeller configurations are key factors in maintaining homogeneity and sufficient mass transfer conditions. Therefore, a flat-folded disc turbine impeller (FFDT) taking into account both the reduced cavitation effect and the increased contact area was designed.

What happens when left meets right under equimolar and non-equimolar co-assembly of short peptide stereoisomers?

The co-assembly of different peptide chains usually leads to the formation of intricate architectures and sophisticated functions in biological systems. Although the co-assembly of stereoisomeric peptides represents a facile and flexible strategy for the synthesis of peptide-based nanomaterials with novel structures and potentially interesting properties, there is a lack of a general knowledge on how different isomers pack during assembly. Through the combined use of simulations and experimental observations, we report that heterochiral pairing is preferred to homochiral pairing at the molecular scale but self-sorting dictates beyond the molecular level for the mixtures of the short stereoisomeric β-sheet peptides IK (Ile-Ile-Ile-Lys).

Controlled Assembly and Disassembly of Higher-Order Peptide Nanotubes.

The controlled peptide self-assembly and disassembly are not only implicated in many cellular processes but also possess huge application potential in a wide range of biotechnology and biomedicine. β-sheet peptide assemblies possess high kinetic stability, so it is usually hard to disassemble them rapidly. Here, we reported that both the self-assembly and disassembly of a designed short β-sheet peptide IIIGGHK could be well harnessed through the variations of concentration, pH, and mechanical stirring.

Amino acid-mediated amorphous copper sulphide with enhanced photothermal conversion efficiency for antibacterial application.

Pathogenic bacteria in daily life, such as Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), often seriously affect human life and health.

Neutron reflection and scattering in characterising peptide assemblies.

Self-assemblies of de novo designed short peptides at interface and in bulk solution provide potential platforms for developing applications in many medical and technological areas. However, characterising how bioinspired supramolecular nanostructures evolve with dynamic self-assembling processes and respond to different stimuli remains challenging. Neutron scattering technologies including small angle neutron scattering (SANS) and neutron reflection (NR) can be advantageous and complementary to other state-of-the-art techniques in tracing structural changes under different conditions.

Recent Advances in the 3D Chiral Plasmonic Nanomaterials.

From the view of geometry, chirality is that an object cannot overlap with its mirror image, which has been a fundamental scientific problem in biology and chemistry since the 19 century. Chiral inorganic nanomaterials serve as ideal templates for investigating chiral transfer and amplification mechanisms between molecule and bulk materials, garnering widespread attentions. The chiroptical property of chiral plasmonic nanomaterials is enhanced through localized surface plasmon resonance effects, which exhibits distinctive circular dichroism (CD) response across a wide wavelength range.

Controlling 1D Nanostructures and Handedness by Polar Residue Chirality of Amphiphilic Peptides.

Peptide assemblies are promising nanomaterials, with their properties and technological applications being highly hinged on their supramolecular architectures. Here, how changing the chirality of the terminal charged residues of an amphiphilic hexapeptide sequence Ac-I K -NH gives rise to distinct nanostructures and supramolecular handedness is reported. Microscopic imaging and neutron scattering measurements show thin nanofibrils, thick nanofibrils, and wide nanotubes self-assembled from four stereoisomers.

Investigation on the Mechanism of PAL (100) Surface Modified by APTES.

The interfacial mechanism has always been a concern for 3-aminopropyltriethoxysilane (APTES)-grafted palygorskite (PAL). In this research, the mechanism of graft modification for grafting of APTES to the surface of PAL (100) was studied using density functional theory (DFT) calculation. The results illustrated that different grafting states of the APTES influence the inter- and intramolecular interactions between APTES/PAL (100), which are reflected in the electronic structures.

Effect of Achiral Glycine Residue on the Handedness of Surfactant-Like Short Peptide Self-Assembly Nanofibers.

Surfactant-like short peptides are a kind of ideal model for the study of chiral self-assembly. At present, there are few studies on the chiral self-assembly of multicharged surfactant-like peptides. In this study, we adopted a series of short peptides of Ac-IKGK-NH with different combinations of -lysine and -lysine residues as the model molecules.

Have the predictability of oil changed during the COVID-19 pandemic: Evidence from international stock markets.

The COVID-19 has undoubtfully brought fierce shocks to the real economic activities, financial market and public lives. Under this special condition, this study explores whether the predictability of crude oil futures information has changed before and during the COVID-19 pandemic for 19 international stock markets. From an in-sample perspective, we find that the crude oil futures RV can significantly affect future stock volatility for each equity index except SSEC.

Surfactant like peptides for targeted gene delivery to cancer cells.

Surfactant like peptides (SLPs) are a class of amphiphilic peptides widely used for drug delivery and tissue engineering. However, there are very few reports on their application for gene delivery. The current study was aimed at development of two new SLPs, named (IA)K and (IG)K, for selective delivery of antisense oligodeoxynucleotides (ODNs) and small interfering RNA (siRNA) to cancer cells.

Racemic Amino Acid Assembly Enables Supramolecular β-Sheet Transition with Property Modulations.

Amino acids are the most simplistic bio-building blocks and perform a variety of functions in metabolic activities. Increasing publications report that amino acid-based superstructures present amyloid-like characteristics, arising from their supramolecular β-sheet secondary structures driven by hydrogen-bonding-connected supramolecular β-strands, which are formed by head-to-tail hydrogen bonds between terminal amino and carboxyl groups of the adjacent residues. Therefore, the establishment of the structure-function relationships is critical for exploring the properties and applications of amino acid assemblies.

Cost-Efficient Production of the Sphingan WL Gum by Sphingomonas sp. WG Using Molasses and Sucrose as the Carbon Sources.

The polysaccharide WL gum is produced by the marine microorganism Sphingomonas sp. WG and presents great commercial utility potential in many industries especially in oil industries. However, the high fermentation cost limits its wide application.

Black Silver Nanocubes@Amino Acid-Encoded Highly Branched Gold Shells with Efficient Photothermal Conversion for Tumor Therapy.

Cancers are among the leading causes of death currently. Conventional radiotherapy and chemotherapy are of limited use in the treatment of some tumors due to their high toxicity and drug resistance. Plasma photothermal therapy has attracted extensive attention for the treatment of tumors due to photothermal properties of plasmonic nanoparticles, such as gold (Au) nanoparticles, to achieve local hyperthermia with low toxicity and high efficiency.

Peptide Self-Assemblies from Unusual α-Sheet Conformations Based on Alternation of d/l Amino Acids.

Peptide self-assembly is a hierarchical process during which secondary structures formed in the initial stages play a critical role in determining the subsequent assembling processes and final structural ordering. Unusual secondary structures hold promise as a source to develop novel supramolecular architectures with unique properties. In this work, we report the design of a new peptide self-assembly strategy based on unusual α-sheet secondary structures.

Core-Shell Structures from the Coassembly of Lipoprotein-like Nanoparticles and Plasmid DNA for Gene Delivery.

We reported self-assembled core-shell nanoparticles (NPs) based on lipoprotein-like NPs and plasmid DNA (pDNA). Lipoprotein-like NPs were prepared using cholic acid (CA)-modified lipopeptides. We designed six different lipopeptides with different peptide segments to construct a series of NPs.

Exploiting terminal charged residue shift for wide bilayer nanotube assembly.

Hypothesis: Self-assembly of peptides is influenced by both molecular structure and external conditions, which dictate the delicate balance of different non-covalent interactions that driving the self-assembling process. The shifting of terminal charge residue is expected to influence the non-covalent interactions and their interplay, thereby affecting the morphologies of self-assemblies. Therefore, the morphology transition can be realized by shifting the position of the terminal charge residue.