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Bridging lectin binding sites by multivalent carbohydrates.

Carbohydrate-protein interactions are involved in a multitude of biological recognition processes. Since individual protein-carbohydrate int … hile chelating binding of the discussed ligands is likely, experimental proof, for example by X-ray crystallography, is limited to only a few cases.

Copper(II) complexes of salicylic acid combining superoxide dismutase mimetic properties with DNA binding and cleaving capabilities display promising chemotherapeutic potential with fast acting in vitro cytotoxicity against cisplatin sensitive and resistant cancer cell lines.

The complexes [Cu(salH)(2)(H(2)O)] (1), [Cu(dipsH)(2)(H(2)O)] (2), {Cu(3-MeOsal)(H(2)O)(0.75)}(n) (3), [Cu(dipsH)(2)(BZDH)(2)] (4), [Cu(dipsH)(2)(2-MeOHBZDH)(2)]·EtOH (5), [Cu(sal)(phen)] (6), [Cu(dips)(phen)]·H(2)O (7), and [Cu(3-MeOsal)(phen)]·H(2)O (8) (salH(2) = salicylic acid; dipsH(2) = 3,5-diisopropylsalicylic acid; 3-MeOsalH(2) = 3-methoxysalicylic acid; BZDH = benzimidazole; 2-MeOHBZDH = 2 methanolbenzimidazole and phen =1,10-phenanthroline) were prepared and characterized. Structures of 4, 5, and 8 were determined by X-ray crystallography. Compounds 1-8 are potent superoxide dismutas…

P2X receptors as drug targets.

The study of P2X receptors has long been handicapped by a poverty of small-molecule tools that serve as selective agonists and antagonists. … termination of the atomic structure of P2X receptors in closed and open (ATP-bound) states by X-ray crystallography is now allowing new approaches by molecular modeling. This is supported by a large body of previous work using mutagenesis and functional expression, and is now being supplemented by molecular dynamic simulations and in silico ligand docking. These …

One pot synthesis of Cu(II) 2,2'-bipyridyl complexes of 5-hydroxy-hydurilic acid and alloxanic acid: synthesis, crystal structure, chemical nuclease activity and cytotoxicity.

A barbiturate derivative [1,5-dihydro-5-[5-pyrimidine-2,4(1H,3H)-dionyl]-2H-chromeno[2,3-d] pyrimidine-2,4(3H)-dione] (LH(4)) was allowed to react with 2,2'-bipyridyl-dinitrato-Copper(II)-dihydrate which provides two complexes, characterized as [Cu(bpy)(L1)]·3H(2)O (1) and [Cu(bpy)(L2)]·H(2)O (2), where bpy = 2,2'-bipyridine, L1 = 5-hydroxy-hydurilic acid and L2 = alloxanic acid. In a separate reaction of LH(4) with Cu(NO(3))(2)·H(2)O another type of complex [Cu(LH(3))(2)·(H(2)O)(2)]·4H(2)O (3) is formed. The complexes were characterized by single crystal X-ray crystallography, physicochemical…

Sulfinylamine metathesis at oxo metal species--convenient entry into imido metal chemistry.

The exchange of terminal metal oxo functionalities by N-organo and N-sulfonylimido functionalities via metathesis with bent, thus very react … aryl imido complexes [Cr(NAr)(2)Cl(2)] Ar = C(6)F(5) and 2,4,6-Cl(3)C(6)H(2) as determined by X-ray crystallography are reported.

New tetraazaannulene hosts for fullerenes.

Two modifications to the doubly concaved host molecules based on well-known nickel tetraazaannulene complexes have resulted in the preparati … C(60).2CS(2) and Ni(Cl(4)TMTAA).C(60).2CS(2) were formed. The compounds were characterized by X-ray crystallography. The crystal structures of the precursor host molecules showed very strong host-host interactions, particularly in the case of Ni(Cl(4)TMTAA), which had short Ni...Ni interactions of 3.3860(11) and 3.5888(11) A in the two different dimers in the asy …

New synthetic procedures to catena-phosphorus cations: preparation and dissociation of the first cyclo-phosphino-halophosphonium salts.

Chlorination of 1,2,3,4-tetracyclohexyl-cyclo-tetraphosphine (2) by PhICl(2) or PCl(5) in the presence of Me(3)SiOTf or GaCl(3) provides a s … hosphonium cations. The compounds have been characterized by NMR spectroscopy, single crystal X-ray crystallography, and Raman spectroscopy.

Структурная основа для преференциального признания незрелых ароматизаторов антителом с синтезом.

Флавивирусы представляют собой группу человеческих патогенов, вызывающих сильные энцефалитные или геморрагические заболевания, включая вирусы Западного Нила, денге и желтой лихорадки. Здесь, с помощью рентгеновской кристаллографии, мы определили структуру реактивного антитела Е53 флавивируса, который включает высокоохранную синтезированную петлю гликпротеина вируса Западного Нила. Используя крио-электронную микроскопию, мы также установили, что E53 Fab связывается преимущественно с пиками неинфекционных, незрелых ароматов, но не может значительно связаться со зрелыми вирионами, что соответству

Совпадение в аннотации оригинала
Flaviviruses are a group of human pathogens causing severe encephalitic or hemorrhagic diseases that include West Nile, dengue and yellow fever viruses. Here, using X-ray crystallography we have defined the structure of the flavivirus cross-reactive antibody E53 that engages the highly conserved fusion loop of the West Nile virus envelope glycoprotein. Using…

Preparation of isotopically labelled recombinant beta-defensin for NMR studies.

beta-Defensins are a family of cationic peptides that contain six invariant cysteine residues that form characteristic disulfide bonds between Cys(1)-Cys(5), Cys(2)-Cys(4) and Cys(3)-Cys(6). They have been shown to act as potent antimicrobial agents and chemokines. Human beta-defensin 2 (HBD2) was first isolated from psoriatic skin lesions and the structure of this peptide has been solved by X-ray crystallography and NMR spectroscopy both of which are consistent with a fold that contains an N-terminal alpha-helix and three antiparallel beta-strands. Here, we report the expression and purificat…

Ruthenium(II) complexes containing bis(2-(diphenylphosphino)phenyl) ether and their catalytic activity in hydrogenation reactions.

The half-sandwich complexes [(eta5-C5H5)RuCl(DPEphos)] (1) and [{(eta6-p-cymene)RuCl2}2(mu-DPEphos)] (2) were synthesized by the reaction of … Cl2(DPEphos)(H2O)(CH3CN)] (8). The structures of the complexes 1-5, 7, and 8 are confirmed by X-ray crystallography. The catalytic activity of these complexes for the hydrogenation of styrene is studied.

Ketolides: an emerging treatment for macrolide-resistant respiratory infections, focusing on S. pneumoniae.

Resistance to antibiotics in community acquired respiratory infections is increasing worldwide. Resistance to the macrolides can be class-specific, as in efflux or ribosomal mutations, or, in the case of erythromycin ribosomal methylase (erm)-mediated resistance, may generate cross-resistance to other related classes. The ketolides are a new subclass of macrolides specifically designed to combat macrolide-resistant respiratory pathogens. X-ray crystallography indicates that ketolides bind to a secondary region in domain II of the 23S rRNA subunit, resulting in an improved structure-activity re…

Sugar-pendant diamines.

A set of 1,3-propanediamine derivatives connected to carbohydrates (5) has been prepared in four steps from peracetylated sugar and 1,3-dibromo-2-propanol in 60-73% yields. D-Glucose, D-mannose, D-galactose, D-xylose, D-ribose, and maltose are utilized as sugar molecules in this work. The diamine moiety was connected to the C1 carbon of the glycopyranose ring via an O-glycoside bond. All of the anomeric configurations and sugar puckering conformations, except in the D-maltose derivative, were determined by X-ray crystallography of the diazido or dibromo precursors. While glycosidation of perac…

Design and Elucidation of a Strain-Relief-Driven Ring Opening Mechanism of Inactivation of Ornithine Aminotransferase by (1S,3R,5R)-3-Amino-6,6-difluorobicyclo[3.1.0]hexane-1-carboxylic Acid.

Human ornithine aminotransferase (hOAT) is a pyridoxal 5'-phosphate (PLP)-dependent enzyme that has been implicated in several cancers due t … OAT. Intact protein mass spectrometry, 19F NMR spectroscopy, transient-state kinetic studies, X-ray crystallography, and QM calculations were used to determine the final adduct and explore the mechanism of inactivation of 5. This is the first report of a ring-opening event in the active site of hOAT.

Expression and Purification of Integral Membrane Enzymes for Functional and Structural Studies.

Enzymes that reside in the membrane are responsible for a myriad of vital tasks such as assembly of and changes to the membrane itself, and … timately yielding the best target not only for successful high-resolution structural analyses-X-ray crystallography and cryogenic electron microscopy in this case-but also for biochemical and biophysical studies.

Probing Macromolecular Interactions by Loss of Solvent Content in Protein Crystals: Application to the Amyloid‑β Peptide Binding to Transthyretin.

X-ray crystallography is commonly used to determine the structure of protein-protein complexes, revealing the atomic details of the interactions between macromolecules in the crystal. However, this technique has limited application in binary systems characterized by transient or weak interactions. Here, we demonstrate that protein crystals can still provide valuable information in such systems by assessing crystal solvent content. We applied this method to investigate the interaction between transthyretin (TTR) and the amyloid beta (Aβ) peptide, a system of interest due to transthyretin's prop…

O-derivatization of natural tropolone and β-thujaplicin leading to effective inhibitors of human carbonic anhydrases IX and XII.

Herein we report the chemical derivatization of the naturally occurring Tropolone (TRP) and its related compound β-Thujaplicin (β-TJP) as we … rofile on healthy cells. The binding mode of β-TJP within the hCA II was assessed by means of X-ray crystallography of the hCA II/β-TJP complex and showed almost complete superposition with the hCA II/TRP adduct reported in the literature. The data produced were used to elaborate a binding prediction model of such compounds on the hCAs VA, IX, and XII which are d …

Mechanistic insights into proton-coupled substrate translocation of nucleoside proton symporters.

The nucleoside proton symporter (NHS) family proteins are part of the major facilitator superfamily and are responsible for transporting nucleosides from the extracellular environment into the cell. Structural and biochemical analysis of NupG, a prototypical NHS member, have pinpointed the critical residues involved in substrate binding. However, the proton-coupled mechanism diving substrate translocation in NHS proteins has remained elusive. In previous research, we identified Asp323 in NupG as a potential protonation site. In this study, using X-ray crystallography, molecular dynamics simula…

From flat to twisted - multifunctional phosphacyclic nanocarbons based on Vat Orange 3.

The field of π-conjugated organic materials has seen significant advances in recent years. However, enhancing the functionality of well-esta … th the dye Vat Orange 3 (VO3) to yield novel nanocarbons with enhanced functional properties. X-ray crystallography reveals distinct twisting of the scaffold in the solid state, while the modification of the phosphorus centers leads to intriguing and versatile photophysics. Thin-film analyses show unusual, pronounced emission features that switch from green to or …

Discovery and mechanism of a highly selective, antifungal acetyl-CoA synthetase inhibitor.

Acetyl-CoA synthetases (Acs) have emerged as drug targets for the treatment of cancer, metabolic diseases as well as fungal and parasitic in … ity for the C. neoformans Acs1 relative to human ACSS2 as well as to other fungal Acs enzymes. Xray crystallography of the isoxazole-CnAcs1 complex revealed that the isoxazole occupies both the acetyl- and CoA-binding sites of CnAcs1. Biochemically, the isoxazoles display uncompetitive inhibition kinetics that are similar to antimalarial Acs inhibitors also propo …

Total Synthesis, Structure Reassignment, and Biological Evaluation of the Anti-Inflammatory Macrolactone 13-Hydroxy-14-deoxyoxacyclododecindione.

Herein, the first total synthesis of natural 13-hydroxy-14-deoxyoxacyclododecindione along with the revision of the proposed configuration i … ined. A detailed analysis of the final macrolactones using spectroscopy (NMR, IR, UV-vis) and X-ray crystallography gave new insights such as the significance of the optical rotation for the elucidation of their configuration and the light-induced E/Z double-bond photoisomerization. The pharmacological potential of the compounds was underlined by remarkably low I …