The straightforward convergent synthesis of sequence‐defined and multifunctionalized macromolecules is described herein. The first combination of two efficient approaches for the synthesis of ...sequence‐defined macromolecules is reported: thiolactone chemistry and the Passerini three‐component reaction (P‐3CR). The thiolactone moiety was used as protecting group for the thiol, allowing the synthesis of a library of sequence‐defined α,ω‐functionalized building blocks. These building blocks were subsequently efficiently coupled to oligomers with carboxylic acid functionalities in a P‐3CR. Thus, larger oligomers with molecular weights of up to 4629.73 g mol−1 were obtained in gram quantities in a convergent approach along with the introduction of independently selectable side chains (up to 15), thus clearly demonstrating the high versatility and the efficiency of the reported approach.
Little by little: The first combination of efficient thiolactone chemistry and the Passerini three‐component reaction (P‐3CR) for the synthesis of sequence‐defined macromolecules is reported. The thiolactone moiety was used as protecting group for the thiol, allowing the synthesis of a library of sequence‐defined α,ω‐functionalized building blocks. These building blocks were subsequently coupled to oligomers to give larger oligomers with molecular weights of up to 4629.73 g mol−1 in gram quantities with up to 15 independently selectable side chains.
The chloroplast adenosine triphosphate (ATP) synthase uses the electrochemical proton gradient generated by photosynthesis to produce ATP, the energy currency of all cells. Protons conducted through ...the membrane-embedded F
motor drive ATP synthesis in the F
head by rotary catalysis. We determined the high-resolution structure of the complete cF
F
complex by cryo-electron microscopy, resolving side chains of all 26 protein subunits, the five nucleotides in the F
head, and the proton pathway to and from the rotor ring. The flexible peripheral stalk redistributes differences in torsional energy across three unequal steps in the rotation cycle. Plant ATP synthase is autoinhibited by a β-hairpin redox switch in subunit γ that blocks rotation in the dark.
Structural flexibility and conformational rearrangements are often related to important functions of biological macromolecules, but the experimental characterization of such transitions with ...high-resolution techniques is challenging. At a lower resolution, small angle X-ray scattering (SAXS) can be used to obtain information on biomolecular shapes and transitions in solution. Here, we present SREFLEX, a hybrid modeling approach that uses normal mode analysis (NMA) to explore the conformational space of high-resolution models and refine the structure guided by the agreement with the experimental SAXS data. The method starts from a given conformation of the protein (which does not agree with the SAXS data). The structure is partitioned into pseudo-domains either using structural classification databases or automatically from the protein dynamics as predicted by the NMA. The algorithm proceeds hierarchically employing NMA to first probe large rearrangements and progresses into smaller and more localized movements. At the large rearrangements stage the pseudo-domains stay as rigid bodies allowing one to avoid structural disruptions inherent to the earlier NMA-based algorithms. To validate the approach, we compiled a representative benchmark set of 88 conformational states known experimentally at high resolution. The performance of the algorithm is demonstrated in the simulated data on the benchmark set and also in a number of experimental examples. SREFLEX is included into the ATSAS program package freely available to the academic users, both for download and in the on-line mode.
SREFLEX employs normal mode analysis for the flexible refinement of atomic models of biological macromolecules against solution scattering data, providing insight into conformational transitions.
Owing to the development of brilliant microfocus beamlines, rapid‐readout detectors and sample changers, protein microcrystallography is rapidly becoming a popular technique for accessing structural ...information from complex biological samples. However, the method is time‐consuming and labor‐intensive and requires technical expertise to obtain high‐resolution protein crystal structures. At SPring‐8, an automated data‐collection system named ZOO has been developed. This system enables faster data collection, facilitates advanced data‐collection and data‐processing techniques, and permits the collection of higher quality data. In this paper, the key features of the functionality put in place on the SPring‐8 microbeam beamline BL32XU are described and the major advantages of this system are outlined. The ZOO system will be a major driving force in the evolution of the macromolecular crystallography beamlines at SPring‐8.
An automated data‐collection system named ZOO has been developed. This system enabled faster data collection, facilitated advanced data‐collection and data‐processing techniques, and permitted the collection of higher quality data.
Since the first application of thermally activated delayed fluorescence (TADF) materials in organic light emitting diodes (OLEDs), rapid development and huge progress have been made. At present, the ...reported TADF materials with high device performance can achieve electroluminescence (EL) with emission colors nearly covering the whole visible ranges. Following the design strategy for TADF small molecules, many macromolecular emitters with different emission colors have been reported to date. Nevertheless, there are realistically a lot of hurdles to surmount when developing low-cost displays and lighting products using macromolecules through the wet processing technology. It confirmedly engrossed us to depict the correlation between emission colors and molecular structures or fabrication of OLED devices in depth. In this context, this review has been written to provide an overview on the TADF mechanism, the design strategy of TADF macromolecules and typical solution-processed polymeric and dendritic emitters organized herein as a function of EL emission colors.
Clinically, multidrug resistant (MDR) bacteria caused by the abuse of antibiotics and the formation of biofilms are the two major obstacles to the treatment of bacterial infections. The utilization ...of noble metal materials has wide prospects to therapy pathogenic bacterial infections as the substitutes of antibiotics. Noble metal nanoparticles (NMNPs), especially gold (Au), silver (Ag), and platinum (Pt), have been attaching great attentions in antimicrobial field, owing to their multiple bactericidal properties, simple synthesis methods, good photo-responsive performance, etc. NMNPs can kill bacteria and eradicate biofilms by disrupting cell membrane potential and stability, binding to biological macromolecules (DNA or enzymes). Additionally, some NMNPs can produce hyperthermia locally or radical oxygen species (ROS). The underlying mechanism is that these NMNPs can be excited under light with different wavelength to exhibit photothermal and photocatalytic effect, aroused by the surface plasmon resonance of activated electrons. In this review, NMNPs and their functionalized nanocomposites for combating pathogenic bacterial infections are reviewed. Herein, the synthetic methods and antibacterial mechanisms of noble metal nanomaterials are discussed. Finally, it’s important to balance antibacterial efficiency and metallic poisoning, specifically for safety assessment in biomedical application. Display omitted
•The synthetic methods of noble metal-based nanomaterials are reviewed.•The antibacterial mechanism of noble metal-based nanomaterials is analyzed.•The methods for noble metal-based nanomaterials to enhance the antibacterial ability are summarized.•It provides insights into the production of high-performance and low-toxic noble metal-based nanomaterials.
The nonlinear optical properties of two novel graphene nanohybrid materials covalently functionalized with porphyrin and fullerene were investigated by using the Z-scan technique at 532 nm in the ...nanosecond and picosecond time scale. Results show that covalently functionalizing graphene with the reverse saturable absorption chromospheres porphyrin and fullerene can enhance the nonlinear optical performance in the nanosecond regime. The covalently linked graphene nanohybrids offer performance superior to that of the individual graphene, porphyrin, and fullerene by combination of a nonlinear mechanism and the photoinduced electron or energy transfer between porphyrin or fullerene moiety and graphene.
Hepatic ischaemia-reperfusion (IR) injury is mainly attributed to a burst of reactive oxygen species (ROS) that attack biological macromolecules and lead to cell death. The superoxide anion (O
˙
) is ...the first ROS to be generated and triggers the production of other ROS; thus, explorations of the role of O
˙
in the IR process are meaningful. Meanwhile, the Golgi apparatus generates O
˙
Golgi-associated proteins, which might play an essential role in IR injury. However, the molecular mechanism by which O
˙
from the Golgi apparatus regulates hepatic IR injury is unclear. Therefore, to solve this problem, a two-photon (TP) excited fluorescence probe (CCA) was designed and prepared for the reversible detection of O
˙
in the Golgi apparatus. With the assistance of TP fluorescence microscopy, we observed a substantial increase in the levels of O
˙
in the Golgi apparatus of an IR mouse liver for the first time, as well as increased caspase-2 activity and apoptosis. Furthermore, we found that the tumour necrosis factor (TNF-α) functions as a positive mediator of O
˙
generation. Based on these data, we identified the potential signalling pathway in the Golgi that mediates O
˙
fluctuations in IR mice and revealed the related molecular mechanisms; we also provide a new target for treating IR injury.
Graphdiyne (GDY) is regarded as an exceptional candidate to meet the growing demand in many fields due to its rich chemical bonds, highly π‐conjugated structure, uniformly distributed pores, large ...surface area, and high inhomogeneity of charge distribution. The extensive research efforts bring about a rapid expansion of GDY with a variety of functionalities, which significantly enhance performance including photocatalysis, energy, biomedicine, etc. In this review, the synthetic strategies (in situ and ex situ approaches) that are designed to rationally functionalize GDY, including optimizing their nanostructures by surface/interface engineering with dopants or functional groups (heteroatoms/small molecules/macromolecules), and building up hierarchical GDY‐based heterostructures are highlighted. Theoretical calculations on the structural evolution and electronic characteristics after the functionalization of GDY are briefly discussed. With elaborate functionalization and rational structure engineering, functional GDY applied in a variety of emerging applications (e.g., hydrogen evolution reaction, CO2 reduction reaction, nitrogen reduction reaction, energy storage and conversion, nanophotonics, sensors, biomedical applications, etc.) are comprehensively discussed. Finally, challenges and prospects concerning the future development of GDY‐based nanoarchitectures are also presented.
To exploit full potential and push the limits of graphdiyne (GDY), numerous functional GDY‐based nanoarchitectures are rationally designed with remarkably improved performances from both theoretical and experimental investigations. It is anticipated that this timely review can pave the way to new designs of functional GDY‐based nanoplatforms for next‐generation nanodevices.
Graphene oxide (GO), which consists of two-dimensional (2D) sp
2
carbon hexagonal networks and oxygen-contained functional groups, has laid the foundation of mass production and applications of ...graphene materials. Made by chemical oxidation of graphite, GO is highly dispersible or even solubilized in water and polar organic solvents, which resolves the hard problem of graphene processing and opens a door to wet-processing of graphene. Despite its defects, GO is easy to functionalize, dope, punch holes, cut into pieces, conduct chemical reduction, form lyotropic liquid crystal, and assemble into macroscopic materials with tunable structures and properties as a living building block. GO sheet has been viewed as a single molecule, a particle, as well as a soft polymer material. An overview on GO as a 2D macromolecule is essential for studying its intrinsic properties and guiding the development of relevant subjects. This review mainly focuses on recent advances of GO sheets, from single macromolecular behavior to macro-assembled graphene material properties. The first part of this review offers a brief introduction to the synthesis of GO molecules. Then the chemical structure and physical properties of GO are presented, as well as its polarity in solvent and rheology behavior. Several key parameters governing the ultimate stability of GO colloidal behavior, including size, pH and the presence of cation in aqueous dispersions, are highlighted. Furthermore, the discovery of GO liquid crystal and functionalization of GO molecules have built solid new foundations of preparing highly ordered, architecture-tunable, macro-assembled graphene materials, including 1D graphene fibers, 2D graphene films, and 3D graphene architectures. The GO-based composites are also viewed and the interactions between these target materials and GO are carefully discussed. Finally, an outlook is provided in this field, where GO is regarded as macromolecules, pointing out the challenges and opportunities that exist in the field. We hope that this review will be beneficial to the understanding of GO in terms of chemical structure, molecular properties, macro-assembly and potential applications, and encourage further development to extend its investigations from basic research to practical applications.
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