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1.
Chemistry ; 30(9): e202303568, 2024 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-38061996

RESUMO

Selected gold complexes have been regarded as promising anti-cancer agents because they can bind with protein targets containing thiol or selenol moieties, but their clinical applications were hindered by the unbiased binding towards off-target thiol-proteins. Recently, a novel gold(III)-hydride complex (abbreviated as 1) with visible light-induced thiol reactivity has been reported as potent photo-activated anticancer agents (Angew. Chem. Int. Ed., 2020, 132, 11139). To explore new strategies to stimuli this potential antitumor drug, the effect of oriented external electric fields (OEEFs) on its geometric structure, electronic properties, and chemical reactivity was systematically investigated. Results reveal that imposing external electric fields along the Au-H bond of 1 can effectively activate this bond, which is conducive to its dissociation and the binding of Au site to potential targets. Hence, this study provides a new OEEF-strategy to activate this reported gold(III)-hydride, revealing its potential application in electrochemical therapy. We anticipate this work could promote the development of more electric field-activated anticancer agents. However, further experimental research should be conducted to verify the conclusions obtained in this work.


Assuntos
Antineoplásicos , Ouro , Ouro/química , Antineoplásicos/química , Eletricidade , Compostos de Sulfidrila
2.
Angew Chem Int Ed Engl ; : e202410514, 2024 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-38966937

RESUMO

Organic scintillators are praised for their abundant element reserves, facile preparation procedures, and rich structures. Herein, a new family of highly efficient organic phosphonium halide salts with thermally activated delayed fluorescence (TADF) are designed by innovatively adopting quaternary phosphonium as the electron acceptor, while dimethylamine group and halide anions (I-) serve as the electron donor. The prepared butyl(2-[2-(dimethylamino)phenyl]phenyl)diphenylphosphonium iodide (C4-I) exhibits bright blue emission and an ultra-high photoluminescence quantum yield (PLQY) of 100%. Efficient charge transfer is realized through the unique n-π and anion-π stacking in solid-state C4-I. Photophysical studies of C4-I suggest that the incorporation of I accounts for high intersystem crossing rate (kISC) and reverse intersystem crossing rate (kRISC), suppressing the intrinsic prompt fluorescence and enabling near-pure TADF emission at room temperature. Benefitting from the large Stokes shift, high PLQY, efficient exciton utilization, and remarkable X-ray attenuation ability endowed by I, C4-I delivers an outstanding light yield of 80721 photons/MeV and a low limit of detection (LoD) of 22.79 nGy·s-1. This work would provide a rational design concept and open up an appealing road for developing efficient organic scintillators with tunable emission, strong X-ray attenuation ability, and excellent scintillator performance.

3.
Phys Chem Chem Phys ; 25(47): 32525-32533, 2023 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-37997746

RESUMO

Catalytic conversion of N2O and CO into nonharmful gases is of great significance to reduce their adverse impact on the environment. The potential of the WSi12 superatom to serve as a new cluster catalyst for CO oxidation by N2O is examined for the first time. It is found that WSi12 prefers to adsorb the N2O molecule rather than the CO molecule, and the charge transfer from WSi12 to N2O results in the full activation of N2O into a physically absorbed N2 molecule and an activated oxygen atom that is attached to an edge of the hexagonal prism structure of WSi12. After the release of N2, the remaining oxygen atom can oxidize one CO molecule via overcoming a rate-limiting barrier of 28.19 kcal mol-1. By replacing the central W atom with Cr and Mo, the resulting MSi12 (M = Cr and Mo) superatoms exhibit catalytic performance for CO oxidation comparable to the parent WSi12. In particular, the catalytic ability of WSi12 for CO oxidation is well maintained when it is extended into tube-like WnSi6(n+1) (n = 2, 4, and 6) clusters with energy barriers of 25.63-29.50 kcal mol-1. Moreover, all these studied MSi12 (M = Cr, Mo, and W) and WnSi6(n+1) (n = 2, 4, and 6) species have high structural stability and can absorb sunlight to drive the catalytic process. This study not only opens a new door for the atomically precise design of new silicon-based nanoscale catalysts for various chemical reactions but also provides useful atomic-scale insights into the size effect of such catalysts in heterogeneous catalysis.

4.
Nature ; 543(7643): 131-135, 2017 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-28219079

RESUMO

Photosystem II (PSII) is a huge membrane-protein complex consisting of 20 different subunits with a total molecular mass of 350 kDa for a monomer. It catalyses light-driven water oxidation at its catalytic centre, the oxygen-evolving complex (OEC). The structure of PSII has been analysed at 1.9 Å resolution by synchrotron radiation X-rays, which revealed that the OEC is a Mn4CaO5 cluster organized in an asymmetric, 'distorted-chair' form. This structure was further analysed with femtosecond X-ray free electron lasers (XFEL), providing the 'radiation damage-free' structure. The mechanism of O=O bond formation, however, remains obscure owing to the lack of intermediate-state structures. Here we describe the structural changes in PSII induced by two-flash illumination at room temperature at a resolution of 2.35 Å using time-resolved serial femtosecond crystallography with an XFEL provided by the SPring-8 ångström compact free-electron laser. An isomorphous difference Fourier map between the two-flash and dark-adapted states revealed two areas of apparent changes: around the QB/non-haem iron and the Mn4CaO5 cluster. The changes around the QB/non-haem iron region reflected the electron and proton transfers induced by the two-flash illumination. In the region around the OEC, a water molecule located 3.5 Å from the Mn4CaO5 cluster disappeared from the map upon two-flash illumination. This reduced the distance between another water molecule and the oxygen atom O4, suggesting that proton transfer also occurred. Importantly, the two-flash-minus-dark isomorphous difference Fourier map showed an apparent positive peak around O5, a unique µ4-oxo-bridge located in the quasi-centre of Mn1 and Mn4 (refs 4,5). This suggests the insertion of a new oxygen atom (O6) close to O5, providing an O=O distance of 1.5 Å between these two oxygen atoms. This provides a mechanism for the O=O bond formation consistent with that proposed previously.


Assuntos
Cristalografia/métodos , Elétrons , Lasers , Luz , Oxigênio/química , Oxigênio/efeitos da radiação , Complexo de Proteína do Fotossistema II/química , Complexo de Proteína do Fotossistema II/efeitos da radiação , Biocatálise/efeitos da radiação , Cianobactérias/química , Transporte de Elétrons/efeitos da radiação , Análise de Fourier , Manganês/química , Manganês/metabolismo , Modelos Moleculares , Ferroproteínas não Heme/química , Ferroproteínas não Heme/metabolismo , Ferroproteínas não Heme/efeitos da radiação , Oxigênio/metabolismo , Complexo de Proteína do Fotossistema II/metabolismo , Prótons , Temperatura , Fatores de Tempo , Água/química , Água/metabolismo
5.
J Integr Plant Biol ; 65(1): 223-234, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36125941

RESUMO

The photosynthetic reaction center complex (RCC) of green sulfur bacteria (GSB) consists of the membrane-imbedded RC core and the peripheric energy transmitting proteins called Fenna-Matthews-Olson (FMO). Functionally, FMO transfers the absorbed energy from a huge peripheral light-harvesting antenna named chlorosome to the RC core where charge separation occurs. In vivo, one RC was found to bind two FMOs, however, the intact structure of RCC as well as the energy transfer mechanism within RCC remain to be clarified. Here we report a structure of intact RCC which contains a RC core and two FMO trimers from a thermophilic green sulfur bacterium Chlorobaculum tepidum at 2.9 Å resolution by cryo-electron microscopy. The second FMO trimer is attached at the cytoplasmic side asymmetrically relative to the first FMO trimer reported previously. We also observed two new subunits (PscE and PscF) and the N-terminal transmembrane domain of a cytochrome-containing subunit (PscC) in the structure. These two novel subunits possibly function to facilitate the binding of FMOs to RC core and to stabilize the whole complex. A new bacteriochlorophyll (numbered as 816) was identified at the interspace between PscF and PscA-1, causing an asymmetrical energy transfer from the two FMO trimers to RC core. Based on the structure, we propose an energy transfer network within this photosynthetic apparatus.


Assuntos
Carcinoma de Células Renais , Chlorobi , Neoplasias Renais , Complexo de Proteínas do Centro de Reação Fotossintética , Complexo de Proteínas do Centro de Reação Fotossintética/química , Complexo de Proteínas do Centro de Reação Fotossintética/metabolismo , Chlorobi/química , Chlorobi/metabolismo , Microscopia Crioeletrônica , Proteínas de Bactérias/metabolismo
6.
Phys Chem Chem Phys ; 23(34): 18908-18915, 2021 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-34612429

RESUMO

Converting earth-abundant nitrogen (N2) gas into ammonia (NH3) under mild conditions is one of the most important issues and a long-standing challenge in chemistry. Herein, a new superatom Ca3B was theoretically designed and characterized to reveal its catalytic performance in converting N2 into NH3 by means of density functional theory (DFT) computations. The alkali-metal-like identity of this cluster is verified by its lower vertical ionization energy (VIE, 4.29 eV) than that of potassium (4.34 eV), while its high stability was guaranteed by the large HOMO-LUMO gap and binding energy per atom (Eb). More importantly, this well-designed superatom possesses unique geometric and electronic features, which can fully activate N2via a "double-electron transfer" mechanism, and then convert the activated N2 into NH3 through a distal reaction pathway with a small energy barrier of 0.71 eV. It is optimistically hoped that this work could intrigue more endeavors to design specific superatoms as excellent catalysts for the chemical adsorption and reduction of N2 to NH3.

7.
J Integr Plant Biol ; 63(10): 1740-1752, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34002536

RESUMO

Photosystem I (PSI) is a large protein supercomplex that catalyzes the light-dependent oxidation of plastocyanin (or cytochrome c6 ) and the reduction of ferredoxin. This catalytic reaction is realized by a transmembrane electron transfer chain consisting of primary electron donor (a special chlorophyll (Chl) pair) and electron acceptors A0 , A1 , and three Fe4 S4 clusters, FX , FA , and FB . Here we report the PSI structure from a Chl d-dominated cyanobacterium Acaryochloris marina at 3.3 Å resolution obtained by single-particle cryo-electron microscopy. The A. marina PSI exists as a trimer with three identical monomers. Surprisingly, the structure reveals a unique composition of electron transfer chain in which the primary electron acceptor A0 is composed of two pheophytin a rather than Chl a found in any other well-known PSI structures. A novel subunit Psa27 is observed in the A. marina PSI structure. In addition, 77 Chls, 13 α-carotenes, two phylloquinones, three Fe-S clusters, two phosphatidyl glycerols, and one monogalactosyl-diglyceride were identified in each PSI monomer. Our results provide a structural basis for deciphering the mechanism of photosynthesis in a PSI complex with Chl d as the dominating pigments and absorbing far-red light.


Assuntos
Clorofila/metabolismo , Cianobactérias/química , Feofitinas/metabolismo , Complexo de Proteína do Fotossistema I/química , Microscopia Crioeletrônica , Cianobactérias/metabolismo , Cianobactérias/ultraestrutura , Transporte de Elétrons , Complexo de Proteína do Fotossistema I/metabolismo , Complexo de Proteína do Fotossistema I/ultraestrutura , Estrutura Quaternária de Proteína
8.
Phys Chem Chem Phys ; 22(16): 8476-8484, 2020 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-32285081

RESUMO

The possibility of using coinage metal atoms as excess electron acceptors is examined for the first time by designing a new class of M+-1-M'- (M = Li, Na, and K; M' = Cu, Ag, and Au) compounds termed "coinage metalides" on the basis of an intriguing Janus-type all-cis1,2,3,4,5,6-hexafluorocyclohexane (1) molecule. Under the large facial polarization of 1, the outermost ns1 electrons of alkali metal atoms can be transferred to coinage metal atoms, forming diffuse excess electrons around them. Consequently, the resulting M+-1-Cu- and M+-1-Ag- compounds exhibit significantly large nonlinear optical (NLO) responses. In particular, these novel M+-1-M'- compounds exhibit much higher stability (larger VIEs and Ec values) than that of the corresponding M+·1·M'- (M, M' = Li, Na, and K) alkalides. We hope this work could open up new possibilities for NLO material design by using coinage metal atoms as excess electron acceptors and, on the other hand, attract more experimental interest and efforts to synthesize such stable compounds in the laboratory.

9.
Photosynth Res ; 139(1-3): 281-293, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29691716

RESUMO

The thermophilic purple sulfur bacterium Thermochromatium tepidum possesses four main water-soluble redox proteins involved in the electron transfer behavior. Crystal structures have been reported for three of them: a high potential iron-sulfur protein, cytochrome c', and one of two low-potential cytochrome c552 (which is a flavocytochrome c) have been determined. In this study, we purified another low-potential cytochrome c552 (LPC), determined its N-terminal amino acid sequence and the whole gene sequence, characterized it with absorption and electron paramagnetic spectroscopy, and solved its high-resolution crystal structure. This novel cytochrome was found to contain five c-type hemes. The overall fold of LPC consists of two distinct domains, one is the five heme-containing domain and the other one is an Ig-like domain. This provides a representative example for the structures of multiheme cytochromes containing an odd number of hemes, although the structures of multiheme cytochromes with an even number of hemes are frequently seen in the PDB database. Comparison of the sequence and structure of LPC with other proteins in the databases revealed several characteristic features which may be important for its functioning. Based on the results obtained, we discuss the possible intracellular function of this LPC in Tch. tepidum.


Assuntos
Chromatiaceae/metabolismo , Grupo dos Citocromos c/química , Grupo dos Citocromos c/metabolismo , Heme/química , Heme/metabolismo , Cristalografia por Raios X , Citocromos c/química , Citocromos c/metabolismo , Transporte de Elétrons/genética , Transporte de Elétrons/fisiologia
10.
Chemistry ; 25(17): 4358-4366, 2019 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-30681743

RESUMO

The potential application of the jellium model as guidance in the rational design of bimetallic superalkali cations is examined under gradient-corrected density functional theory for the first time. By using Li, Mg, and Al as atomic building blocks, a series of bimetallic cationic clusters with 2, 8, 20, and 40 valence electrons are obtained and investigated. As the corresponding neutral clusters tend to lose one valence electron to achieve closed-shell states in the jellium model, these studied cations exhibit much lower vertical electron affinities (EAvert , 3.42-4.95 eV) than the ionization energies (IEs) of alkali metal atoms, indicating their superalkali identities. The high stability of these cationic clusters is guaranteed by their considerable HOMO-LUMO gaps and binding energies per atom. Moreover, the feasibility of using the designed superalkalis as efficient reductants to activate CO2 and N2 molecules and as stable building blocks to assemble ionic superatom compounds is explored. Therefore, this study may provide an effective method for obtaining various metallic superatoms with extensive applications on the basis of the simple jellium rule.

11.
Environ Sci Technol ; 53(5): 2820-2829, 2019 03 05.
Artigo em Inglês | MEDLINE | ID: mdl-30761900

RESUMO

Legacy organic contaminants, such as polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs), and several currently used organic contaminants, such as novel brominated retardants (NBFRs), organophosphate flame retardants (OPFRs), and Dechlorane Plus (DPs), were measured in the segmented hair and hand wipes of e-waste dismantling workers and in the dust from their workplace in an e-waste recycling site in South China to assess the accumulation and sources of organic contaminants in the hair shaft. The median concentrations of DPs, PBDEs, NBFRs, PCBs and OPFRs in hair samples were 23.5, 154, 156, 349, and 371 ng/g, respectively. A linear increase in organic contaminant concentrations was found along the hair shaft, with significant differences among each segment, while the age-related patterns were similar among the 7 hair segments. A linear relationship was found between the accumulation rates and the log KOW, indicating that the accumulation rates of organic contaminants along the hair shaft decreased with increasing log KOW values. Enantiomer fraction (EF) values of PCB-132 in distal segments were close to those in dust and air, while EFs in proximal segments were close to those in serum. The contributions of PCBs from external sources to hair increased with the distance from the scalp of hair segments, from 67.8% in 0-3 cm segments to 95.9% in 18-21 cm segments.


Assuntos
Resíduo Eletrônico , Retardadores de Chama , Bifenilos Policlorados , China , Poeira , Monitoramento Ambiental , Feminino , Cabelo , Éteres Difenil Halogenados , Humanos , Local de Trabalho
12.
Yao Xue Xue Bao ; 52(3): 474-80, 2017 Mar.
Artigo em Zh | MEDLINE | ID: mdl-29979862

RESUMO

In this study, the endocytosis pathway of heparosan and its intracellular distribution were investigated in MCF-7 tumor cells and COS7 normal cells. The endocytosis inhibition and cellular probe location experiments showed that MCF-7 tumor cells took heparosan more efficiently and selectively than COS7 cells. The cellular uptake of heparosan was energy-dependent in both MCF-7 tumor cells and COS7 normal cells. Moreover, the major endocytosis pathway of heparosan into MCF-7 tumor cells was caveolin-mediated endocytosis and macropinocytosis. The internalized heparosan was mainly located in lysosomes of the cells.


Assuntos
Dissacarídeos/farmacocinética , Endocitose , Lisossomos , Pinocitose , Animais , Células COS , Chlorocebus aethiops , Humanos , Células MCF-7
13.
Chemphyschem ; 17(10): 1468-74, 2016 05 18.
Artigo em Inglês | MEDLINE | ID: mdl-26923480

RESUMO

Based on the density functional theory for exchange-correlation potential, fluorocarbon molecular cages are investigated as building blocks of hyperhalogens. By utilizing C8 F7 as a ligand, a series of hyperhalogen anions, that is, M(C8 F7 )2 (-) (M=Li, Na, and K) and M(C8 F7 )3 (-) (M=Be, Mg, and Ca), are modeled. Calculations show that all the C8 F7 moieties preserve their geometric and electronic integrity in these anions. These anionic molecules possess larger vertical electron detachment energies (5.11-6.45 eV) than that of C8 F7 (-) , verifying their hyperhalogen nature. Moreover, it is also revealed that using larger fluorinated cage C10 F9 as ligands can bring about hyperhalogen anions with larger vertical electron detachment energies. The stability of these studied anions is determined by their large HOMO-LUMO gaps and positive dissociation energies of predetermined possible fragmentation pathways. It is hoped this study will provide an approach for the construction of new types of hyperhalogens and stimulate more research in superatom chemistry.

14.
Chemphyschem ; 17(17): 2672-8, 2016 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-27219640

RESUMO

Guided by density functional theory (DFT) computations, a new series of superalkali-based alkalides, namely FLi2 (+) (aza222)K(-) , OLi3 (+) (aza222)K(-) , NLi4 (+) (aza222)K(-) , and Li3 (+) (aza222)K(-) were designed with various superalkali clusters embedded into an aza222 cage-complexant. These species possess diverse isomeric structures in which the encapsulated superalkalis preserve their identities and behave as alkali metal atoms. The results show that these novel alkalides possess larger complexation energies and enhanced hyperpolarizabilities (ß0 ) compared with alkali-metal-based and previous superalkali-based clusters. Especially, a prominent structural dependence of ß0 is observed for these studied compounds. Hence, the geometric factors that affect the nonlinear optical (NLO) response of such alkalides is elucidated in detail in this work. This study not only provides novel candidates for alkalides, it also offers an effective way to enhance the NLO response and stability of alkalides.

15.
Chemphyschem ; 17(23): 3907-3915, 2016 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-27644001

RESUMO

Excess-electron compounds can be considered as novel candidates for nonlinear optical (NLO) materials because of their large static first hyperpolarizabilities (ß0 ). A room-temperature-stable, excess-electron compound, that is, the organic electride Na@(TriPip222), was successfully synthesized by the Dye group (J. Am. Chem. Soc. 2005, 127, 12416). In this work, the ß0 of this electride was first evaluated to be 1.13×106  au, which revealed its potential as a high-performance NLO material. In particular, the substituent effects of different substituents on the structure, electride character, and NLO response of this electride were systemically studied for the first time by density functional theory calculations. The results revealed that the ß0 of Na@(TriPip222) could be further increased to 8.30×106  au by introducing a fluoro substituent, whereas its NLO response completely disappeared if one nitryl group was introduced because the nitro-group substitution deprived the material of its electride identity. Moreover, herein the dependence of the NLO properties on the number of substituents and their relative positions was also detected in multifluoro-substituted Na@(TriPip222) compounds.

16.
Guang Pu Xue Yu Guang Pu Fen Xi ; 35(11): 3161-6, 2015 Nov.
Artigo em Zh | MEDLINE | ID: mdl-26978928

RESUMO

In this work, cadmium nitrate hexahydrate [Cd(NO3)2 · 6H2O] is as a source of cadmium, zinc nitrate [Zn(NO3)2] as a source of zinc source, and NaHSe as a source of selenium which was prepared through reducing the elemental selenium with sodium borohydride (NaBH4). Then water-soluble Cd1₋xZnxSe ternary quantum dots with different component were prepared by colloid chemistry. The as-prepared Cd1₋xZnx Se ternary quantum dots exhibit stable fluorescent property in aqueous solution, and can still maintain good dispersivity at room temperature for four months. Powder X-ray diffraction (XRD) and high resolution transmission electron microscope (HRTEM) were used to analyze crystal structure and morphology of the prepared Cd1₋xZnxSe. It is found that the as-prepared ternary quantum dots are cubic phase, show as sphere, and the average of particle size is approximate 4 nm. The spectral properties and energy band structure of the as-prepared ternary quantum dots were modulated through changing the atom ratio of elements Zn and Cd. Compared with binary quantum dots CdSe and ZnSe, the ultraviolet-visible (UV-Visible) absorption spectrum and fluorescence (FL) emission spectrum of ternary quantum dots are both red-shift. The composites (Cd0.5 Zn0.5 Se@TNTs) of Cd0.5 Zn0.5 Se ternary quantum dots and TiO2 nanotubes (TNTs) were prepared by directly immerging TNTs into quantum dots dispersive solution for 5 hours. TEM image shows that the Cd0.5 Zn0.5 Se ternary quantum dots were closely combined to nanotube surface. The infrared spectra show that the Ti-Se bond was formed between Cd0.5 Zn0.5 Se ternary quantum dots and TiO2 nanotubes, which improve the stability of the composite. Compared to pristine TNTs, UV-Visible absorption spectrum of the composites is significantly enhanced in the visible region of light. And the absorption band edge of Cd0.5Zn0.5 Se@TNTs red-shift from 400 to 700 nm. The recombination of the photogenerated electron-hole pairs was restrained with the as-prepared ternary quantum dots. Therefore, the visible-light photocatalytic efficiency was greatly improved. After visible-light irradiation for 60 min, the degradation of Cd0.5 Zn0.5 Se@TNTs photocatalysts for RhB is nearly 100%, which is about 3. 3 times of that of pristine TNTs and 2. 5 times of that of pure Cd0.5 Zn0.5 Se ternary quantum dots, respectively.

17.
Sci Adv ; 10(8): eadk7140, 2024 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-38394197

RESUMO

Acaryochloris marina is a unique cyanobacterium using chlorophyll d (Chl d) as its major pigment and thus can use far-red light for photosynthesis. Photosystem II (PSII) of A. marina associates with a number of prochlorophyte Chl-binding (Pcb) proteins to act as the light-harvesting system. We report here the cryo-electron microscopic structure of a PSII-Pcb megacomplex from A. marina at a 3.6-angstrom overall resolution and a 3.3-angstrom local resolution. The megacomplex is organized as a tetramer consisting of two PSII core dimers flanked by sixteen symmetrically related Pcb proteins, with a total molecular weight of 1.9 megadaltons. The structure reveals the detailed organization of PSII core consisting of 15 known protein subunits and an unknown subunit, the assembly of 4 Pcb antennas within each PSII monomer, and possible pathways of energy transfer within the megacomplex, providing deep insights into energy transfer and dissipation mechanisms within the PSII-Pcb megacomplex involved in far-red light utilization.


Assuntos
Complexo de Proteína do Fotossistema II , Proclorófitas , Complexo de Proteína do Fotossistema II/metabolismo , Clorofila/metabolismo , Fotossíntese
18.
J Mol Graph Model ; 118: 108378, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36423518

RESUMO

The potential application of an experimentally synthesized superatom Ti@Si16 as a novel drug carrier for cisplatin (DDP), isoniazid (INH), acetylsalicylic acid (ASA), 5-fluorouracil (5-Fu), and favipiravir (FPV) has been explored by density functional theory. It is observed that the Pt atom of DDP can be effectively absorbed on Ti@Si16 via a "donation-back donation" electron transfer mechanism, resulting in a moderate adsorption energy of -19.95 kcal/mol for DDP@[Ti@Si16]. As for INH, it prefers to combine with Ti@Si16 via the N atom of pyridine ring by forming a strongly polar N-Si bond. Differently, the interaction between Ti@Si16 and the ASA, 5-Fu, and FPV drugs is dominated by the Van der Waals interaction. Our results reveal that DDP@[Ti@Si16] possesses a moderate recovery time under body temperature, which benefits the desorption of DDP from Ti@Si16. More importantly, the release of DDP drug from the Ti@Si16 surface can be effectively controlled by exerting small orientation external electric fields on the DDP@[Ti@Si16] complex. Therefore, this study demonstrates that Ti@Si16 can serve as a promising drug carrier for DDP, and thus will further expand its practical applications in the biomedical field.


Assuntos
Portadores de Fármacos , Titânio , Sistemas de Liberação de Medicamentos , Fluoruracila , Cisplatino , Aspirina
19.
J Mol Graph Model ; 125: 108617, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37696119

RESUMO

Developing novel nanoscale carriers for drug delivery is of great significance for improving treatment efficiency and reducing side effects of antitumor drugs. In view of the good biocompatibility and special affinity of porphyrin (PP) molecule to cancer cells, it was used to construct a series of metal-doped M@PP (M = Ca âˆ¼ Zn) materials for the delivery of anticancer drug 5-fluorouracil (5-Fu) in this work. Our results reveal that 5-Fu is tightly adsorbed on M@PP (M = Ca âˆ¼ V, Mn âˆ¼ Co, and Zn) by chemisorption, but is physically adsorbed by M@PP (M = Cr, Ni, and Cu). The calculated electronic properties show that all these 5-Fu@[M@PP] (M = Ca âˆ¼ Zn) complexes have both high stability and solubility. Among these 5-Fu@[M@PP] complexes, the chemical bond formed between 5-Fu and Ti@PP has the strongest covalent characteristic, resulting in the largest adsorption energy of -19.93 kcal/mol for 5-Fu@[Ti@PP]. In particular, 5-Fu@[Ti@PP] has the proper recovery time under the near-infrared light at body temperature, which further suggests that Ti@PP is the best drug carrier for 5-Fu. This study not only reveals the interaction strength and nature between 5-Fu and M@PP, but also confirmed the intriguing potential of Ti@PP as nano-carrier for drug delivery. However, further experimental research should be conducted to verify the conclusion obtained in this work.


Assuntos
Antineoplásicos , Metaloporfirinas , Portadores de Fármacos , Fluoruracila/farmacologia , Sistemas de Liberação de Medicamentos
20.
Cancer Innov ; 2(4): 240-252, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38089745

RESUMO

Background: No well-performing nomogram has been developed specifically to predict individual-patient cancer-specific survival (CSS) and overall survival (OS) among patients with resectable colorectal liver metastasis (CRLM) who undergo simultaneous resection of primary and hepatic lesions without neoadjuvant chemotherapy (NAC). We aim to investigate the prognosis of patients with resectable CRLM undergoing simultaneous resection of primary and hepatic lesions without NAC. Methods: Data of patients with CRLM in the Surveillance, Epidemiology and End Results Program (cohort, n = 225) were collected as the training set, and data of patients with CRLM treated at the National Cancer Center (cohort, n = 180) were collected as the validation set. The prognostic value of the clinicopathological parameters in the training cohort was assessed using Kaplan‒Meier curves and univariate and multivariate Cox proportional hazards models, and OS and CSS nomograms integrated with the prognostic variables were constructed. Calibration analyses, receiver operating characteristic (ROC) curves, and decision curve analyses (DCAs) were then performed to evaluate the performance of the nomograms. Results: There was no collinearity among the collected variables. Three factors were associated with OS and CSS: the pretreatment carcinoembryonic antigen (CEA) concentration, pathologic N (pN) stage, and adjuvant chemotherapy (each p < 0.05). OS and CSS nomograms were constructed using these three parameters. The calibration plots revealed favorable agreement between the predicted and observed outcomes. The areas under the ROC curves were approximately 0.7. The DCA plots revealed that both nomograms had satisfactory clinical benefits. The ROC curves and DCAs also confirmed that the nomogram surpassed the tumor, node, and metastasis staging system. Conclusion: The herein-described nomograms containing the pretreatment CEA concentration, pN stage, and adjuvant chemotherapy may be effective models for predicting postoperative survival in patients with CRLM.

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