Institutt for kjemi: Recent submissions
Now showing items 241-260 of 611
-
The crystal structure of the tetrameric DABA-aminotransferase EctB, a rate-limiting enzyme in the ectoine biosynthesis pathway
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-02-29)L‐2,4‐diaminobutyric acid (DABA) aminotransferases can catalyze the formation of amines at the distal ω‐position of substrates, and is the intial and rate‐limiting enzyme in the biosynthesis pathway of the cytoprotecting molecule (S)‐2‐methyl‐1,4,5,6‐tetrahydro‐4‐pyrimidine carboxylic acid (ectoine). Although there is an industrial interest in the biosynthesis of ectoine, the DABA aminotransferases ... -
A Polymer Magician: Professor Charlotte K. Williams
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-08-28)At Organometallics, the Editorial Team has been highlighting a number of scientists that we feel have had a profound impact on the field and perhaps also on ourselves. In this editorial, I wish to introduce another of our Pioneers and Influencers, Professor Charlotte K. Williams from Oxford University. Professor Williams works on three things I love: homogeneous metal catalysts, carbon dioxide, and ... -
Biochemical characterization of ferric uptake regulator (Fur) from Aliivibrio salmonicida. Mapping the DNA sequence specificity through binding studies and structural modelling
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-07-09)Iron is an essential nutrient for bacteria, however its propensity to form toxic hydroxyl radicals at high intracellular concentrations, requires its acquisition to be tightly regulated. Ferric uptake regulator (Fur) is a metal-dependent DNA-binding protein that acts as a transcriptional regulator in maintaining iron metabolism in bacteria and is a highly interesting target in the design of new ... -
Structure and mechanism of a phage-encoded SAM lyase revises catalytic function of enzyme family
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-02-10)The first S-adenosyl methionine (SAM) degrading enzyme (SAMase) was discovered in bacteriophage T3, as a counter-defense against the bacterial restriction-modification system, and annotated as a SAM hydrolase forming 5’ methyl-thioadenosine (MTA) and L-homoserine. From environmental phages, we recently discovered three SAMases with barely detectable sequence similarity to T3 SAMase and without ... -
Molecular Structure of Copper and μ-Oxodiiron Octafluorocorrole Derivatives: Insights into Ligand Noninnocence
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-04-23)Single-crystal X-ray structures were obtained for the copper and μ-oxodiiron complexes of 2,3,7,8,12,13,17,18-octafluoro-5,10,15-triphenylcorrole, hereafter denoted as Cu[F8TPC] and {Fe[F8TPC]}2O. A comparison with the crystal structures of other undecasubstituted Cu corroles, including those with H, Ar, Br, I, and CF3 as β-substituents, showed that the degree of saddling increases in the order: H ... -
Protonation-Induced Hyperporphyrin Spectra of meso-Aminophenylcorroles
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-04-06)UV–vis spectrophotometric titrations have been carried out on <i>meso</i>-tris(<i>o/m/p</i>-aminophenyl)corrole (H<sub>3</sub>[<i>o/m/p</i>-TAPC]) and meso-triphenylcorrole (H<sub>3</sub>[TPC]) in dimethyl sulfoxide with methanesulfonic acid (MSA). Monoprotonation was found to result in hyperporphyrin spectra characterized by new, red-shifted, and intense Q bands. The effect was particularly dramatic ... -
Facile Supramolecular Engineering of Porphyrin cis Tautomers: The Case of β-Octabromo-meso-tetraarylporphyrins
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-04-02)A porphyrin cis tautomer, where the two central NH protons are on adjacent pyrrole rings, has long been invoked as an intermediate in porphyrin tautomerism. Only recently, however, has such a species been isolated and structurally characterized. Thus, single-crystal X-ray structure determinations of two highly saddled free-base porphyrins, β-heptakis(trifluoromethyl)-meso-tetrakis(p-fluorophenyl)porphyrin, ... -
Nature of the copper-nitrosyl intermediates of copper nitrite reductases during catalysis
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-10-20)The design and synthesis of copper complexes that can reduce nitrite to NO has attracted considerable interest. They have been guided by the structural information on the catalytic Cu centre of the widespread enzymes Cu nitrite reductases but the chemically novel side-on binding of NO observed in all crystallographic studies of these enzymes has been questioned in terms of its functional relevance. ... -
X-ray absorption spectroscopy of archetypal chromium porphyrin and corrole derivatives
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-05-29)A combination of Cr K-edge XAS and DFT calculations have been performed on archetypal chromium porphyrinoid complexes Cr<sup>IV</sup>[TMP]O (<b>2</b>) and Cr<sup>V</sup>[TPC]O (<b>3</b>), and the results have been compared to the reference compound Cr<sup>III</sup>[TPP]Cl (<b>1</b>), where TPP<sup>2−</sup>, TMP<sup>2−</sup>, and TPC<sup>3−</sup> are the anions of <i>meso</i>-tetraphenylporphyrin, ... -
The high catalytic rate of the cold-active Vibrio alkaline phosphatase requires a hydrogen bonding network involving a large interface loop
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-11-16)The role of surface loops in mediating communication through residue networks is still a relatively poorly understood part in the study of cold adaptation of enzymes, especially in terms of their quaternary interactions. Alkaline phosphatase (AP) from the psychrophilic marine bacterium <i>Vibrio splendidus</i> (VAP) is characterized by an analogous large surface loop in each monomer, referred to as ... -
1H, 13C, 15N resonance assignment of the apo form of the small, chitin-active lytic polysaccharide monooxygenase JdLPMO10A from Jonesia denitrificans
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-11-19)The lytic polysaccharide monooxygenase <i>Jd</i>LPMO10A is the N-terminal domain of the multimodular protein Jd1381. The isolated <i>Jd</i>LPMO10A domain is one of the smallest chitin-active lytic polysaccharide monooxygenases known to date with a size of only 15.5 kDa. <i>Jd</i>LPMO10A is a copper-dependent oxidative enzyme that depolymerizes chitin by hydroxylating the C1 carbon in the glycosidic ... -
nsroot: Minimalist process isolation tool implemented with Linux namespaces
(Journal article; Tidsskriftartikkel, 2017-11-26)Data analyses in the life sciences are moving from tools run on a personal computer to services run on large computing platforms. This creates a need to package tools and dependencies for easy installation, configuration and deployment on distributed platforms. In addition, for secure execution there is a need for process isolation on a shared platform. Existing virtual machine and container ... -
Synthesis and molecular structure of perhalogenated rhenium-oxo corroles
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-11-12)As part of our efforts to develop rhenium-oxo corroles as photosensitizers for oxygen sensing and photodynamic therapy, we investigated the potential <i>β</i>-perhalogenation of five ReO <i>meso</i>-tris(<i>para</i>-X-phenyl)corroles, Re[T<i>p</i>XPC](O) (X = CF<sub>3</sub>, H, F, CH<sub>3</sub>, and OCH<sub>3</sub>), with elemental chlorine and bromine. With Cl<sub>2</sub>, <i>β</i>-octachlorinated ... -
Iridium corroles exhibit weak near-infrared phosphorescence but efficiently sensitize singlet oxygen formation
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-05-05)Six-coordinate iridium(III) triarylcorrole derivatives, Ir[T<i>p</i>XPC)]L<sub>2</sub>, where T<i>p</i>XPC = tris(para-X-phenyl)corrole (X = CF<sub>3</sub>, H, Me, and OCH<sub>3</sub>) and L = pyridine (py), trimethylamine (tma), isoquinoline (isoq), 4-dimethylaminopyridine (dmap), and 4-picolinic acid (4pa), have been examined, with a view to identifying axial ligands most conducive to near-infrared ... -
Description of the uEMEP_v5 downscaling approach for the EMEP MSC-W chemistry transport model
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-12-11)A description of the new air quality downscaling model – the urban EMEP (uEMEP) and its combination with the EMEP MSC-W model (European Monitoring and Evaluation Programme Meteorological Synthesising Centre West) – is presented. uEMEP is based on well-known Gaussian modelling principles. The uniqueness of the system is in its combination with the EMEP MSC-W model and the “local fraction” calculation ... -
Unequivocal structure confirmation of a breitfussin analog by anisotropic NMR measurements
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-09-21)Structural features of proton-deficient heteroaromatic natural products, such as the breitfussins, can severely complicate their characterization by NMR spectroscopy. For the breitfussins in particular, the constitution of the five-membered oxazole central ring cannot be unequivocally established via conventional NMR methods when the 4′-position is halogenated. The level of difficulty is exacerbated ... -
X-ray crystal structure of Vibrio alkaline phosphatase with the non-competitive inhibitor cyclohexylamine
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-10-15)<i>Background</i> - <i>Para</i>-nitrophenyl phosphate, the common substrate for alkaline phosphatase (AP), is available as a cyclohexylamine salt. Here, we report that cyclohexylamine is a non-competitive inhibitor of APs.<br><br> <i>Methods</i> - Cyclohexylamine inhibited four different APs. Co-crystallization with the cold-active <i>Vibrio</i> AP (VAP) was performed and the structure solved.<br><br> ... -
Structural insight into DNA joining: from conserved mechanisms to diverse scaffolds
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-05-04)DNA ligases are diverse enzymes with essential functions in replication and repair of DNA; here we review recent advances in their structure and distribution and discuss how this contributes to understanding their biological roles and technological potential. Recent high-resolution crystal structures of DNA ligases from different organisms, including DNA-bound states and reaction intermediates, have ... -
A scalable and green one-minute synthesis of substituted phenols
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-11-07)A mild, green and highly efficient protocol was developed for the synthesis of substituted phenols via <i>ipso</i>-hydroxylation of arylboronic acids in ethanol. The method utilizes the combination of aqueous hydrogen peroxide as the oxidant and H<sub>2</sub>O<sub>2</sub>/HBr as the reagent under unprecedentedly simple and convenient conditions. A wide range of arylboronic acids were smoothly ... -
Methanotroph populations and CH 4 oxidation potentials in High Arctic peat are altered by herbivory induced vegetation change
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-07-08)Methane oxidizing bacteria (methanotrophs) within the genus <i>Methylobacter</i> constitute the biological filter for methane (CH<sub>4</sub>) in many Arctic soils. Multiple <i>Methylobacter</i> strains have been identified in these environments but we seldom know the ecological significance of the different strains. High-Arctic peatlands in Svalbard are heavily influenced by herbivory, leading to ...