Autocatalytic ring opening of N-acylaziridines : Complete control over regioselectivity by orientation at interfaces

Contains fulltext : 14059.pdf (publisher's version ) (Open Access

Copper(II) complexes of a dicephalic imidazole surfactant. Tunable organization of metalloaggregates

Contains fulltext : 14144.pdf (publisher's version ) (Open Access

Synthesis and crystal structure of (+)-(2R,3R)-N, N '-bis-trityl-2,3-bis-aziridine

Contains fulltext : 14200.pdf (publisher's version ) (Open Access

Cationic gemini Surfactants based on tartaric acid: Synthesis, aggregation, monolayer behaviour, and interaction with DNA

Contains fulltext : 13999.pdf (publisher's version ) (Open Access

Assemblies of aziridinemethanols

Contains fulltext : 14060.pdf (publisher's version ) (Open Access

Distorted octahedral coordination of tungstate in a subfamily of specific binding proteins

Bacteria and archaea import molybdenum and tungsten from the environment in the form of the oxyanions molybdate (MoO4 2−) and tungstate (WO4 2−). These substrates are captured by an external, high-affinity binding protein, and delivered to ATP binding cassette transporters, which move them across the cell membrane. We have recently reported a crystal structure of the molybdate/tungstate binding protein ModA/WtpA from Archaeoglobus fulgidus, which revealed an octahedrally coordinated central metal atom. By contrast, the previously determined structures of three bacterial homologs showed tetracoordinate molybdenum and tungsten atoms in their binding pockets. Until then, coordination numbers above four had only been found for molybdenum/tungsten in metalloenzymes where these metal atoms are part of the catalytic cofactors and coordinated by mostly non-oxygen ligands. We now report a high-resolution structure of A. fulgidus ModA/WtpA, as well as crystal structures of four additional homologs, all bound to tungstate. These crystal structures match X-ray absorption spectroscopy measurements from soluble, tungstate-bound protein, and reveal the details of the distorted octahedral coordination. Our results demonstrate that the distorted octahedral geometry is not an exclusive feature of the A. fulgidus protein, and suggest distinct binding modes of the binding proteins from archaea and bacteri

Characterization of a [4Fe-4S]-ferredoxin model based on a concave tetradentate thiol ligand system

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Feature extraction of Jabon (Anthocephalus sp) leaf disease using discrete wavelet transform

Jabon (Anthocephalus cadamba (Roxb.) Miq) is one type of forest plants that have very rapid growth until the process of the harvest. One inhibitor is a disease that attacks the leaves in the form of spots and blight that can cause death during the growth process of this tree. The purpose of this process is to detect the object of diseases that attack the leaves of jabon at the time in the nursery. Images of affected jabon leaf disease segmented by reducing the RGB color cylinders to separate the disease object from the background. Reduced channel G-R provides information in the form of disease areas contained in the image of Jabon leaf. Furthermore, the characteristics of leaf disease can be detected well using DWT in the 3-level decomposition process with SVM classification results that can separate both classes of spots and blight by 84.672%

Emission of volatile halogenated compounds, speciation and localization of bromine and iodine in the brown algal genome model Ectocarpus siliculosus

This study explores key features of bromine and iodine metabolism in the filamentous brown alga and genomics model Ectocarpus siliculosus. Both elements are accumulated in Ectocarpus, albeit at much lower concentration factors (2-3 orders of magnitude for iodine, and < 1 order of magnitude for bromine) than e.g. in the kelp Laminaria digitata. Iodide competitively reduces the accumulation of bromide. Both iodide and bromide are accumulated in the cell wall (apoplast) of Ectocarpus, with minor amounts of bromine also detectable in the cytosol. Ectocarpus emits a range of volatile halogenated compounds, the most prominent of which by far is methyl iodide. Interestingly, biosynthesis of this compound cannot be accounted for by vanadium haloperoxidase since the latter have not been found to catalyze direct halogenation of an unactivated methyl group or hydrocarbon so a methyl halide transferase-type production mechanism is proposed