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Intramolecular coupling of acetylenic groups of bis(alkynyl)phosphanes and silanes mediated by benzynezirconocene: a route to new mono- and tricyclic…
2004
Benzo-zirconacyclohexadiene-phospha or silacyclobutene fused ring systems are easily prepared via a benzynezirconocene intermediate by means of thermolysis of Cp 2 ZrPh 2 in the presence of bis(alkynyl)phosphanes or silanes. These polyunsaturated systems are the source of a variety of new mono- or tricyclic heterocycles incorporating either one or two heteroatoms.
Affinity Cleavage of Carbamoyl-Phosphate Synthetase I Localizes Regions of the Enzyme Interacting with the Molecule of ATP that Phosphorylates Carbam…
1995
Two ATP molecules are used in the reaction catalyzed by carbamoyl-phosphate synthetase I. One molecule (ATPA) phosphorylates HCO3- and the other (ATPB) phosphorylates carbamate. Carbamoyl-phosphate synthetase I is a 160-kDa polypeptide consisting of a 40-kDa N-terminal moiety and a 120-kDa C-terminal moiety, the latter being composed of two similar halves of molecular mass 60 kDa. We showed [Alonso, E., Cervera, J., Garcia-Espana, A., Bendala, E. & Rubio, V. (1992) J. Biol. Chem. 267, 4524-4532] that Fe.ATP bound at the site for ATPB catalyzes the oxidative inactivation of carbamoyl-phosphate synthetase I in a model oxidative system consisting of Fe3+, ascorbate, and O2, and we detected ATP…
Genetic Systems for Monitoring Interactions of Transmembrane Domains in Bacterial Membranes
2013
In recent years several systems have been developed to study interactions of TM domains within the inner membrane of the Gram-negative bacterium Escherichia coli. Mostly, a transmembrane domain of interest is fused to a soluble DNA-binding domain, which dimerizes in E. coli cytoplasm after interactions of the transmembrane domains. The dimeric DNA-binding domain subsequently binds to a promoter/operator region and thereby activates or represses a reporter gene. In 1996 the first bacterial system has been introduced to measure interactions of TM helices within a bacterial membrane, which is based on fusion of a transmembrane helix of interest to the DNA-binding domain of the Vibrio cholerae …
Excited State N−H Tautomer Selectivity in the Singlet Energy Transfer of a Zinc(II)-Porphyrin-Truxene-Corrole Assembly
2017
International audience; An original corrole-containing polyad for S-1 energy transfer, in which one zinc(II)-porphyrin donor is linked to two free-base corrole acceptors by a truxene linker, is reported. This polyad exhibits a rapid zinc(II)-porphyrin*free-base corrole transfer (4.83x10(10)s(-1); 298K), even faster than the tautomerization in the excited state processes taking advantage of the good electronic communication provided by the truxene bridge. Importantly, the energy transfer process shows approximately 3-fold selectivity for one corrole N-H tautomer over the other even at low temperature (77K). This selectivity is due to the difference in the J-integral being effective in both t…
The Aluminyl Anion : A New Generation of Aluminium Nucleophile
2020
Trivalent aluminium compounds are well known for their reactivity as Lewis acids/electrophiles, a feature that is exploited in many pharmaceutical, industrial and laboratory-based reactions. Recently, a series of isolable aluminium(I) anions ('aluminyls') have been reported, which offer an alternative to this textbook description: these reagents behave as aluminium nucleophiles. This minireview covers the synthesis, structure and reactivity of aluminyl species reported to date, together with their associated metal complexes. The frontier orbitals of each of these species have been investigated using a common methodology to allow for a like-for-like comparison of their electronic structure a…
Removal of Chromophore-proximal Polar Atoms Decreases Water Content and Increases Fluorescence in a Near Infrared Phytofluor
2015
Genetically encoded fluorescent markers have revolutionized cell and molecular biology due to their biological compatibility, controllable spatiotemporal expression, and photostability. To achieve in vivo imaging in whole animals, longer excitation wavelength probes are needed due to the superior ability of near infrared light to penetrate tissues unimpeded by absorbance from biomolecules or autofluorescence of water. Derived from near infrared-absorbing bacteriophytochromes, phytofluors are engineered to fluoresce in this region of the electromagnetic spectrum, although high quantum yield remains an elusive goal. An invariant aspartate residue is of utmost importance for photoconversion in…
The primary structural photoresponse of phytochrome proteins captured by a femtosecond X-ray laser
2020
Please check the README file for more information about the dataset.
The hedgehog receptor patched is involved in cholesterol transport.
2011
International audience; BACKGROUND: Sonic hedgehog (Shh) signaling plays a crucial role in growth and patterning during embryonic development, and also in stem cell maintenance and tissue regeneration in adults. Aberrant Shh pathway activation is involved in the development of many tumors, and one of the most affected Shh signaling steps found in these tumors is the regulation of the signaling receptor Smoothened by the Shh receptor Patched. In the present work, we investigated Patched activity and the mechanism by which Patched inhibits Smoothened. METHODOLOGY/PRINCIPAL FINDINGS: Using the well-known Shh-responding cell line of mouse fibroblasts NIH 3T3, we first observed that enhancement …
¿Quién decide qué y cómo? el conflicto en torno a la participación ciudadana en el contexto del desarrollo de la iniciativa urbana: Cuenca-San Antón …
2018
This article describes the main results of an ethnographic study on citizen participation carried out in the context of the development of the Urban Initiative (2007-2015): Cuenca-Barrio de San Antón. Managed by the City Council of Cuenca and financed by the European Regional Development Funds (FEDER) under the Ministry of Economy and Finance at the Government of Spain The results of the research show how in the context of the application of neoliberal policies, citizen participation becomes the trigger for new conflicts between institutions and citizens. In this sense, it is worth noting how, in practice, institutions in their capacity as experts and not willing to dis-empower themselves, …
Nonlinear beam self-cleaning in a coupled cavity composite laser based on multimode fiber
2017
International audience; We study a coupled cavity laser configuration where a passively Q-switched Nd:YAG microchip laser is combined with an extended cavity, including a doped multimode fiber. For appropriate coupling levels with the extended cavity, we observed that beam self-cleaning was induced in the multimode fiber thanks to nonlinear modal coupling, leading to a quasi-single mode laser output. In the regime of beam self-cleaning, laser pulse duration was reduced from 525 to 225 ps. We also observed a Q-switched mode-locked operation, where spatial self-cleaning was accompanied by far-detuned nonlinear frequency conversion in the active multimode fiber.