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131.
Masterson LR Tonelli M Markley JL Veglia G 《Journal of the American Chemical Society》2008,130(25):7818-7819
We present a procedure for isolating subspectra corresponding to individual protein or peptide components in a ternary mixture or complex. Each of the three-component species is labeled differently: species A uniformly with 15N, species B uniformly with 15N and 13C, and species C uniformly with 15N but selectively with 13C' or 13Calpha. By using the dual carbon label selective HSQC (DCLS-HSQC) pulse sequence and exploiting differences in 1J 15N-13C coupling patterns to filter selected 15N resonances from detection during a constant time period, a subspectrum from each species can be generated from three spectra acquired from a single sample. Many important biological pathways involve dynamic interactions among members of multicomponent protein assemblies, and this approach offers a powerful way to monitor such processes. 相似文献
132.
Li Hao Wang Yingjie Ye Manping Li Shanshan Li Deyong Ren Haisheng Wang Mohan Du Luchao Li Heng Veglia Gianluigi Gao Jiali Weng Yuxiang 《中国科学:化学(英文版)》2020,63(8):1121-1133
Major light-harvesting complex of photosystem Ⅱ(LHCⅡ) plays a dual role in light-harvesting and excited energy dissipation to protect photodamage from excess energy. The regulatory switch is induced by increased acidity, temperature or both. However,the molecular origin of the protein dynamics at the atomic level is still unknown. We carried out temperature-jump time-resolved infrared spectroscopy and molecular dynamics simulations to determine the energy quenching dynamics and conformational changes of LHCⅡ trimers. We found that the spontaneous formation of a pair of local α-helices from the 310-helix E/loop and the C-terminal coil of the neighboring monomer, in response to the increased environmental temperature and/or acidity, induces a scissoring motion of transmembrane helices A and B, shifting the conformational equilibrium to a more open state, with an increased angle between the associated carotenoids. The dynamical and allosteric conformation change leads to close contacts between carotenoid lutein 1 and chlorophyll pigment 612, facilitating the fluorescence quenching. Based on these results, we suggest a unified mechanism by which the LHCⅡ trimer controls the dissipation of excess excited energy in response to increased temperature and acidity, as an intrinsic result of intense sun light in plant photosynthesis. 相似文献
133.
Dr. Gianluigi Albano Dr. Francesco Zinna Francesco Urraci Prof. Maria Annunziata M. Capozzi Prof. Gennaro Pescitelli Prof. Angela Punzi Prof. Lorenzo Di Bari Prof. Gianluca M. Farinola 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(51):e202201178
The chiroptical features of chiral diketopyrrolo[3,4-c]pyrrole (DPP) derivatives have been only marginally investigated to date. In this regard, we have synthesized ad hoc four chiral DPP dyes, functionalized with enantiopure alkyl groups from natural sources either on the lactam moieties or on the terminal positions of the π-conjugated backbone, to promote an efficient self-assembly into chiral supramolecular structures. For each of them, the aggregation modes has been investigated by absorbance and ECD spectroscopies in conditions of solution aggregation and on thin films, considering the effects of deposition technique (drop casting vs. spin coating) and post-deposition operations (solvent and thermal annealing). The effect of the structure of lateral π-conjugated units attached to the central DPP scaffold, as well as that of the position of the alkyl chiral group, has been assessed. ECD revealed superior capability, compared to absorbance spectroscopy, to provide information on the aggregation modes and to detect the possible co-existence of multiple aggregation pathways. 相似文献
134.
Dr. Gianluigi Albano Dr. Laura Antonella Aronica Dr. Alessandro Minotto Prof. Franco Cacialli Prof. Lorenzo Di Bari 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(70):16622-16627
This work reports the first observation of circularly polarized electroluminescence (CPEL) in thin films of self-organized oligothiophenes. Four new 1,4-phenylene and 9H-carbazole-based oligothiophenes were ad hoc designed to ensure efficient spontaneous formation of chiral supramolecular order. They were easily synthesized and their chiroptical properties in thin films were measured. Circularly polarized luminescence (CPL) spectra revealed glum in the order of 10−2 on a wide wavelengths range, originating from their self-organized chiral supramolecular organization. These molecules have reasonable properties as organic semiconductors and for this reason they can constitute the active layer of circularly-polarized organic light-emitting diodes (CP-OLEDs). Thus, we could investigate directly their electroluminescence (EL) and CPEL, without resorting to blends, but rather in a simple multilayer device with basic architecture. This is the first example of a CP-OLED with active layer made only of a small organic compound. 相似文献
135.
Mauro Dalla Palma Davide Gaule Antonio Pimazzoni Roberto Pasqualotto Gianluigi Serianni Bernd Böswirth Henri Greuner 《Journal of Thermal Analysis and Calorimetry》2018,132(1):143-154
Carbothermic reduction of chromite in the presence of nickel as the alloying element was investigated in a wide temperature range up to 1500 °C using thermogravimetric analysis coupled with continuous off-gas analysis (TG-DSC-MS). Both isothermal and non-isothermal linear heating tests were performed for the kinetic study with the calculation of activation energies. In order to further elucidate the reduction mechanism, the reduced products were characterized by SEM–EDS and XRD. It was concluded that the reduction sequence followed a multi-stage mechanism, reflected partly by the dependency of the activation energy on the extent of reduction. With the progress of reduction, refractory oxide layers gradually formed on/close to the surface of each chromite particle, causing the shift of the rate-limiting factor from chemical control to diffusion control. The promoting effect from the addition of Ni was evident at temperatures higher than 1300 °C due to the formation of alloys of lower melting point. 相似文献
136.
Sergio De Nicola Renato Fedele Margarita A. Man’ko Vladimir I. Man’ko Riccardo Meucci Gianluigi Zito 《Journal of Russian Laser Research》2010,31(2):139-151
The Fresnel tomograms of Laguerre–Gaussian beams are found and the relation of the two-point spatial correlation function
with the tomographic map is discussed. The spatial distribution and signature of vorticity of Laguerre–Gaussian modes is analyzed
by measuring the two-point spatial correlation function of the one-dimensional projection of the vortex field. An interferometric
approach, based on a Fourier projection algorithm, for the experimental determination of the two-point correlation function
of the full complex vortex field at the cross-section plane of the recorded interference pattern is also described; this approach
allows one to characterize the vortex structure and spatial coherence along the direction of propagation. 相似文献
137.
138.
Gaetano Cammilleri Andrea Pulvirenti Innocenzo Ezio Giangrosso Gianluigi Maria Lo Dico Giovanna Montana 《Natural product research》2020,34(1):177-182
AbstractWe assessed the relationship between V, Cr, Mn, Hg, As, Cd, Sn, Sb and Pb concentrations in Mytilus galloprovincialis samples from the coasts of Sicily and the expression of metallothioneins. Toxic mineral elements assessment was carried out by A.A. Spectrometry and ICP-MS. The metallothioneins expression was performed by q-PCR method. Low metals’ levels were found in the mussel samples examined, in comparison with what was reported in literature. The highest mean values of toxic mineral elements were found in Gela (Cr 0.178?±?0.03?mg/Kg, Mn 4.325?±?0.012?mg/Kg, As 3.706?±?0.009?mg/Kg, Sn 0.148?±?0.014?mg/Kg, Sb 0.009?±?0.004?mg/Kg e Pb 0.364?±?0.01?mg/Kg). Significant levels of Hg were found in samples from Catania (0.014?±?0.005?mg/Kg). Only vanadium and lead concentrations showed significant differences between sampling areas (p?<?0.05). Molecular analysis verified a basal expression of Mt1 and the absence of over-expression of Mt2, confirming the low mineral’s concentrations found in the samples examined. 相似文献
139.
Gaetano Cammilleri Mirella Vazzana Vincenzo Arizza Francesca Giunta Antonio Vella Gianluigi Lo Dico 《Natural product research》2018,32(4):457-462
A total of 205 bluefin and yellowfin tuna samples were examined for mercury detection in order to verify possible differences and have a detailed risk assessment of the two tuna species. The results showed significant higher mercury concentration in muscle tissue of bluefin tuna respect yellowfin tuna (p < 0.001) with mean concentration of 0.84 mg/kg and maximum value of 1.94 mg/kg. These differences can be due the different biological and ecological aspects of the two tuna species and to different oceanographic aspects between Atlantic Ocean and Mediterranean sea. The results obtained in this study suggest an advisable containment of the sources of pollution and further studies on the closed-loop farming of bluefin tuna, in order to ensure the product safety. 相似文献
140.
A novel synthetic strategy based on the intramolecular palladium-catalyzed oxidative cyclization reaction, allows the formation of C-C bond and the synthesis of β-carbolinones. The reaction has been performed in the presence of catalytic amount of PdCl2(CH3CN)2 and benzoquinone as a reoxidant. 相似文献