Search results for "Azide"
showing 10 items of 334 documents
N‐Terminal Modification of Gly‐His‐Tagged Proteins with Azidogluconolactone
2021
Site-specific protein modifications are vital for biopharmaceutical drug development. Gluconoylation is a non-enzymatic, post-translational modification of N-terminal HisTags. We report high-yield, site-selective inâ vitro α-aminoacylation of peptides, glycoproteins, antibodies, and virus-like particles (VLPs) with azidogluconolactone at pHâ 7.5 in 1â h. Conjugates slowly hydrolyse, but diol-masking with borate esters inhibits reversibility. In an example, we multimerise azidogluconoylated SARS-CoV-2 receptor-binding domain (RBD) onto VLPs via click-chemistry, to give a COVID-19 vaccine. Compared to yeast antigen, HEK-derived RBD was immunologically superior, likely due to observed diffe…
Improved AMYR program: an algorithm for the theoretical simulation of molecular associations, including geometrical and topological characterization …
1991
Program AMYR, originally written by S. Fraga (University of Alberta, Canada), allows for the calculation of molecular associations using a pair-wise atom-atom potential. The interaction energy is evaluated through a 1/R expansion. Our improved version includes a dispersion energy term in the potential corrected by damping functions, the possibility of carrying out energy minimizations through variable metric methods, as well as the optional calculation of geometrical and topological indices. Program AMYR has been adapted also for high-performance computing and vectorization. An interactive version of the program carries out real-time molecular graphics showing simultaneously the energy prof…
Coordination Polymers Containing Manganese(II)-Azido Layers Connected by Dipyridyl-tetrazine and 4,4′-Azobis(pyridine) Linkers
2013
Two new polynuclear manganese(II) complexes [Mn(dptz)(N(3))(2)](n) (1) and [Mn(azpy)(N(3))(2)](n) (2) (where dptz = dipyridyl-tetrazine and azpy = 4,4'-azobis(pyridine)) have been synthesized by self-assembly of the ligand azide, together with dptz and azpy as secondary spacers. The compounds are characterized by single-crystal X-ray diffraction analyses and variable-temperature magnetic measurements. The structural analyses reveal that in complex 1, which is the first reported Mn(II) complex with the ligand dptz, two μ(1,3) bridging azides connect neighboring manganese ions in a zigzag manner to generate a neutral two-dimensional (2D) sheet which is further connected by the dptz ligands to…
Click chemistry-assisted bioconjugates for hapten immunodiagnostics
2020
Bioorthogonal reactions have revolutionized the way low molecular weight compounds are coupled to biomolecules. Organic chemistry, polymer science, and chemical biology are among the disciplines that are benefited the most from this breakthrough. Despite the reliability of the click chemistry concept for the efficient and chemoselective functionalization of biomacromolecules with haptens at preferred positions, the fact that azide–alkyne cycloaddition reactions originate new chemical moieties as part of the linker may have delayed their application in the immunodiagnostic field. Using the mycotoxin ochratoxin A as a model compound, we herein demonstrate for the first time that bioconjugates…
A novel bio-orthogonal cross-linker for improved protein/protein interaction analysis
2015
International audience; The variety of protein cross-linkers developed in recent years illustrates the current requirement for efficient reagents optimized for mass spectrometry (MS) analysis. To date, the most widely used strategy relies on commercial cross-linkers that bear an isotopically labeled tag and N-hydroxysuccinimid-ester (NHS-ester) moieties. Moreover, an enrichment step using liquid chromatography is usually performed after enzymatic digestion of the cross-linked proteins. Unfortunately, this approach suffers from several limitations. First, it requires large amounts of proteins. Second, NHS-ester cross-linkers are poorly efficient because of their fast hydrolysis in water. Fin…
2,8-Diazido-ATP — a short-length bifunctional photoaffinity label for photoaffinity cross-linking of a stable F1 in ATP synthase (from thermophilic b…
1995
Abstract To demonstrate the direct interfacial position of nucleotide binding sites between subunits of proteins we have synthesized the bifunctional photoaffinity label 2,8-diazidoadenosine 5′-triphosphate (2,8-DiN3ATP). UV irradiation of the F1-ATPase (TF1) from the thermophilic bacterium PS3 in the presence of 2,8-DiN3ATP results in a nucleotide-dependent inactivation of the enzyme and in a nucleotide-dependent formation of α-β crosslinks. The results confirm an interfacial localization of all the nucleotide binding sites on TF1.
Site-by-site tracking of signal transduction in an azidophenylalanine-labeled bacteriophytochrome with step-scan FTIR spectroscopy
2021
Signal propagation in photosensory proteins is a complex and multidimensional event. Unraveling such mechanisms site-specifically in real time is an eligible but a challenging goal. Here, we elucidate the site-specific events in a red-light sensing phytochrome using the unnatural amino acid azidophenylalanine, vibrationally distinguishable from all other protein signals. In canonical phytochromes, signal transduction starts with isomerization of an excited bilin chromophore, initiating a multitude of processes in the photosensory unit of the protein, which eventually control the biochemical activity of the output domain, nanometers away from the chromophore. By implementing the label in pri…
Syntheses, crystal structures, and oxidative DNA cleavage of some Cu(II) complexes of 5-amino-3-pyridin-2-yl-1,2,4-triazole
2004
Three new monomeric Cu(II) complexes of 5-amino-3-pyridin-2-yl-1,2,4-triazole (Hapt), [Cu(Hapt)(H(2)O)(2)(SO(4))] (1), [Cu(Hapt)(2)(H(2)O)(NO(3))](NO(3)) (2), and [Cu(Hapt)(2)(NCS-N)](NCS).H(2)O (3), have been prepared and characterized by single crystal X-ray diffraction. One distorted [CuN(2)O(2)+O(')] square-pyramidal (1), one distorted [CuN(3)O+N(')+O(')] octahedral (2), and one distorted [CuN(4)+N(')] intermediate between square-pyramidal and trigonal-bipyramidal (3) coordination configuration were found and are suggested to be due to the chelating nature of the ligand, which interacts with Cu(II) through the N4(triazole) and N(pyridine) atoms. Spectral properties of these chelates are…
CCDC 1880657: Experimental Crystal Structure Determination
2021
Related Article: Ramadan M. Ramadan, Samir M. El���Medani, Abdelmoneim Makhlouf, Hussein Moustafa, Manal A. Afifi, Matti Haukka, Ayman Abdel Aziz|2021|Appl.Organomet.Chem.|35|e6246|doi:10.1002/aoc.6246
The azide/tetrazole equilibrium: an investigation in the series of furo- and thieno[2,3-e]tetrazolo[3,2-d]pyrimidine derivatives
2016
Abstract Starting from 7(8)-chlorofuro(thieno)[3,2- d ]pyrimidines 1 , the corresponding 7(8)-hydrazinofuro(thieno)[3,2- d ]pyrimidines 2 were obtained by reaction with hydrazine. By treatment with nitrous acid, compounds 2 gave fused furo- and thieno[2,3- e ]tetrazolo[1,5- c ]pyrimidines 3 T and 4 T in excellent yields, which in solution exist in equilibrium with 7(8)-azidofuro(thieno)[3,2- d ]pyrimidines 3 A and 4 A . Compounds 3 T / 3 A and 4 T / 4 A represent useful substrates for investigating the azide/tetrazole equilibrium: it has been examined as a function of solvent, temperature, and their structure. We have observed that, in solution, in both 3 and 4 the equilibrium was strongly …