• Band structures and Z2 invariants of two-dimensional transition metal dichalcogenide monolayers from fully relativistic Dirac-Kohn-Sham theory using Gaussian-type orbitals 

      Kadek, Marius; Wang, Baokai; Joosten, Marc; Chiu, Wei-Chi; Mairesse, Francois; Repisky, Michal; Ruud, Kenneth; Bansil, Arun (Journal article; Tidsskriftartikkel, 2023-06-02)
      Two-dimensional (2D) materials exhibit a wide range of remarkable phenomena, many of which owe their existence to the relativistic spin-orbit coupling (SOC) effects. To understand and predict properties of materials containing heavy elements, such as the transition-metal dichalcogenides (TMDs), relativistic effects must be taken into account in first-principles calculations. We present an all-electron ...
    • Behind the scenes of spin-forbidden decay pathways in transition metal complexes 

      Moitra, Torsha; Karak, Pijush; Chakraborty, Sayantani; Ruud, Kenneth; Chakrabarti, Swapan (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-11-10)
      The interpretation of the ultrafast photophysics of transition metal complexes following photo-absorption is quite involved as the heavy metal center leads to a complicated and entangled singlet–triplet manifold. This opens up multiple pathways for deactivation, often with competitive rates. As a result, intersystem crossing (ISC) and phosphorescence are commonly observed in transition metal complexes. ...
    • Benchmarking the Performance of Exchange-Correlation Functionals for Predicting Two-Photon Absorption Strengths 

      Beerepoot, Maarten; Alam, MD Mehboob; Bednarska, Joanna; Bartkowiak, Wojciech; Ruud, Kenneth; Zaleśny, Robert (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-05-31)
      The present work investigates the performance of exchange–correlation functionals in the prediction of two-photon absorption (2PA) strengths. For this purpose, we considered six common functionals used for studying 2PA processes and tested these on six organoboron chelates. The set consisted of two semilocal (PBE and BLYP), two hybrid (B3LYP and PBE0), and two range-separated (LC-BLYP and CAM-B3LYP) ...
    • Benchmarking two-photon absorption cross sections: performance of CC2 and CAM-B3LYP 

      Beerepoot, Maarten T. P.; Friese, Daniel Henrik; List, Nanna Holmgaard; Kongsted, Jacob; Ruud, Kenneth (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-06-25)
      We investigate the performance of CC2 and TDDFT/CAM-B3LYP for the calculation of two-photon absorption (TPA) strengths and cross sections and contrast our results to a recent coupled cluster equation-of-motion (EOM-EE-CCSD) benchmark study [K. D. Nanda and A. I. Krylov, J. Chem. Phys., 2015, 142, 064118]. In particular, we investigate whether CC2 TPA strengths are significantly overestimated compared ...
    • Biochemical and biophysical characterization of the OXA-48-like carbapenemase OXA-436 

      Lund, Bjarte Aarmo; Thomassen, Ane Molden; Carlsen, Trine Josefine Warg; Leiros, Hanna-Kirsti Schrøder (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-08-31)
      The crystal structure of the class D β-lactamase OXA-436 was solved to a resolution of 1.80 Å. Higher catalytic rates were found at higher temperatures for the clinically important antibiotic imipenem, indicating better adaptation of OXA-436 to its mesophilic host than OXA-48, which is believed to originate from an environmental source. Furthermore, based on the most populated conformations during ...
    • Biochemical and structural characterisation of a family GH5 cellulase from endosymbiont of shipworm P. megotara 

      Junghare, Madan; Manavalan, Tamilvendan; Fredriksen, Lasse; Leiros, Ingar; Altermark, Bjørn; Eijsink, Vincent; Vaaje-Kolstad, Gustav (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-04-04)
      Background Cellulases play a key role in the enzymatic conversion of plant cell-wall polysaccharides into simple and economically relevant sugars. Thus, the discovery of novel cellulases from exotic biological niches is of great interest as they may present properties that are valuable in the biorefning of lignocellulosic biomass. Results We have characterized a glycoside hydrolase 5 (GH5) domain ...
    • Biochemical characterization of a family 15 carbohydrate esterase from a bacterial marine Arctic metagenome 

      De Santi, Concetta; Willassen, Nils Peder; Williamson, Adele Kim (Journal article; Tidsskriftartikkel; Peer reviewed, 2016)
      Background The glucuronoyl esterase enzymes of wood-degrading fungi (Carbohydrate Esterase family 15; CE15) form part of the hemicellulolytic and cellulolytic enzyme systems that break down plant biomass, and have possible applications in biotechnology. Homologous enzymes are predicted in the genomes of several bacteria, however these have been much less studied than their fungal counterparts. ...
    • Biochemical characterization of ferric uptake regulator (Fur) from Aliivibrio salmonicida. Mapping the DNA sequence specificity through binding studies and structural modelling 

      Berg, Kristel; Pedersen, Hege Lynum; Leiros, Ingar (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 ...
    • Biochemical characterization of ParI, an orphan C5-DNA methyltransferase from Psychrobacter arcticus 273-4 

      Grgic, Miriam; Williamson, Adele Kim; Bjerga, Gro Elin Kjæreng; Altermark, Bjørn; Leiros, Ingar (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-05-25)
      <p>Cytosine-specific DNA methyltransferases are important enzymes in most living organisms. In prokaryotes, most DNA methyltransferases are members of the type II restriction-modification system where they methylate host DNA, thereby protecting it from digestion by the accompanying restriction endonucleases. DNA methyltransferases can also act as solitary enzymes having important roles in controlling ...
    • Biological Evaluations, NMR Analyses, Molecular Modeling Studies, and Overview of the Synthesis of the Marine Natural Product (−)-Mucosin 

      Nolsøe, Jens Mortansson Jelstrup; Underhaug, Jarl; Sørskår, Åshild Moi; Antonsen, Simen; Malterud, Karl Egil; Gani, Osman; Fan, Qiong; Hjorth, Marit; Sæther, Thomas; Hansen, Trond Vidar; H. Stenstrøm, Yngve (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-02-24)
      Natural products obtained from marine organisms continue to be a rich source of novel structural architecture and of importance in drug discovery, medicine, and health. However, the success of such endeavors depends on the exact structural elucidation and access to sufficient material, often by stereoselective total synthesis, of the isolated natural product of interest. (−)-Mucosin (1), a fatty ...
    • Bioprospecting around Arctic islands: Marine bacteria as rich source of biocatalysts 

      De Santi, Concetta; Altermark, Bjørn; de Pascale, Donatella; Willassen, Nils Peder (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-12-11)
      We have investigated the biotechnological potential of Arctic marine bacteria for their ability to produce a broad spectrum of cold-active enzymes. Marine bacteria exhibiting these features are of great interest for both fundamental research and industrial applications. Macrobiota water and sediment samples have been collected during 2010 and 2011expeditions around the Lofoten and Svalbard islands. ...
    • Bipartite Genomes in Enterobacterales: Independent Origins of Chromids, Elevated Openness and Donors of Horizontally Transferred Genes 

      Sonnenberg, Cecilie Bækkedal; Haugen, Peik (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-02-21)
      Multipartite bacteria have one chromosome and one or more chromid. Chromids are believed to have properties that enhance genomic flexibility, making them a favored integration site for new genes. However, the mechanism by which chromosomes and chromids jointly contribute to this flexibility is not clear. To shed light on this, we analyzed the openness of chromosomes and chromids of the two bacteria, ...
    • The Blue–Violet Color of Pentamethylbismuth: A Visible Spin-Orbit Effect 

      Conradie, Jeanet; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-12-22)
      Two-component relativistic time-dependent density functional theory calculations with spin-orbit coupling predict yellow and orange–red absorption for BiPh5 and BiMe5, respectively, providing an excellent explanation for their respective violet and blue–violet colors. According to the calculations, the visible absorption is clearly attributable to a single transition from a ligand-based HOMO ...
    • Bulky, electron-rich, renewable: analogues of Beller's phosphine for cross-couplings 

      van der Westhuizen, Danielle; Castro, Abril C; Hazari, Nilay; Gevorgyan, Ashot (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-10-30)
      In recent years, considerable progress has been made in the conversion of biomass into renewable chemicals, yet the range of value-added products that can be formed from biomass remains relatively small. Herein, we demonstrate that molecules available from biomass serve as viable starting materials for the synthesis of phosphine ligands, which can be used in homogeneous catalysis. Specifically, ...
    • Caesium Fluoride-Mediated Hydrocarboxylation of Alkenes and Allenes: Scope and Mechanistic Insights 

      Gevorgyan, Ashot; Obst, Marc; Guttormsen, Yngve; Maseras, Feliu; Hopmann, Kathrin Helen; Bayer, Annette (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-09-11)
      A caesium fluoride-mediated hydrocarboxylation of olefins is disclosed that does not rely on precious transition metal catalysts and ligands. The reaction occurs at atmospheric pressures of CO<sub>2</sub> in the presence of 9-BBN as a stoichiometric reductant. Stilbenes, β-substituted styrenes and allenes could be carboxylated in good yields. The developed methodology can be used for preparation of ...
    • Caffeine supplementation does not affect match activities and fatigue resistance during match play in young football players 

      Pettersen, Svein Arne; Krustrup, Peter; Bendiksen, Mads; Randers, Morten B.; Brito, Joao; Bangsbo, Jens; Yun, Jin; Mohr, Magni (Journal article; Tidsskriftartikkel; Peer reviewed, 2014-10-30)
      The study examined the effect of caffeine supplementation on match activities and development of fatigue during a football match. In a randomised, double-blind cross-over design, two experimental football games separated by 7 days were organised between the junior teams of two professional football clubs (17.6 ± 1.1 years (±s), 71.7 ± 6.9 kg, 13.9% ± 5.0% body fat). The players ingested either a ...
    • Calculations of the EPR g-tensor using unrestricted two- and four-component relativistic approaches within the HF and DFT frameworks 

      Cherry, Peter J.; Komorovsky, Stanislav; Malkin, Vladimir G.; Malkina, Olga L. (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-06-08)
      Approaches and programs for calculations of the EPR g-tensor in the framework of the two- and four-component methods are still very rare. There are three main reasons for this: the wider community's unawareness of the importance of second- and higher order spin–orbit effects on the g-tensor, the methodological problems associated with performing such calculations and the lack of understanding of ...
    • Can the absolute configuration of cyclic peptides be determined with vibrational circular dichroism? 

      Eikås, Karolina Di Remigio; Monika, Krupová; Kristoffersen, Tone; Beerepoot, Maarten; Ruud, Kenneth (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-04-16)
      Cyclic peptides show a wide range of biological activities, among others as antibacterial agents. These peptides are often large and flexible with multiple chiral centers. The determination of the stereochemistry of molecules with multiple chiral centers is a challenging and important task in drug development. Chiroptical spectroscopies such as vibrational circular dichroism (VCD) can ...
    • Carbon-carbon bonds with CO2: Insights from computational studies 

      Obst, Marc; Pavlovic, Ljiljana; Hopmann, Kathrin Helen (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-02-17)
      In this mini-review, we provide an overview of recent computational studies on homogeneous transition metal-catalyzed carbon-carbon bond formation with CO2. We cover substitution and addition reactions involving different metals (mainly Ni, Rh, Cu) and substrates (alkanes, alkenes, alkynes, arenes) with focus on the mechanistic details. The CO2 insertion step is generally found to be rate-limiting. ...
    • Carbonylative Suzuki-Miyaura couplings of sterically hindered aryl halides: Synthesis of 2-aroylbenzoate derivatives 

      Ismael, Aya; Skrydstrup, Troels; Bayer, Annette (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-02-10)
      We have developed a carbonylative approach to the synthesis of diversely substituted 2-aroylbenzoate esters featuring a new protocol for the carbonylative coupling of aryl bromides with boronic acids and a new strategy to favour carbonylative over non-carbonylative reactions. Two different synthetic pathways – (i) the alkoxycarbonylation of 2-bromo benzophenones and (ii) the carbonylative Suzuki–Miyaura ...