Now showing items 222-241 of 251

    • Species diversity and abundance of shipworms (Mollusca: Bivalvia: Teredinidae) in woody marine debris generated by the Great East Japan Earthquake and Tsunami of 2011 

      Treneman, Nancy C.; Carlton, James T.; Borges, Luisa M. S.; Shipway, Reuben; Raupach, Michael; Altermark, Bjørn (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-02)
      The Tohoku tsunami of March 2011 ejected a vast amount of debris into the Pacific Ocean. Wood boring shipworms (Bivalvia: Teredinidae) were either already present in, or settled on, the wooden fraction of this debris, offering a unique opportunity to study shipworm diversity in rafted wood of a known origin and time of ocean entry. Lumber and other wood began appearing on Central Pacific (Hawaiian ...
    • Spin-rotation and NMR shielding constants in HCl 

      Jaszunski, Michal; Repisky, Michal; Demissie, Taye B.; Komorovsky, Stanislav; Malkin, Elena; Ruud, Kenneth; Garbacz, Piotr; Jackowski, Karol; Makulski, W (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      The spin-rotation and nuclear magnetic shielding constants are analysed for both nuclei in the HCl molecule. Nonrelativistic ab initio calculations at the CCSD(T) level of approximation show that it is essential to include relativistic effects to obtain spin-rotation constants consistent with accurate experimental data. Our best estimates for the spin-rotation constants of 1H35Cl are CCl =−53.914 ...
    • The Spot 42 RNA: A regulatory small RNA with roles in the central metabolism 

      Haugen, Peik; Bækkedal, Cecilie (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-09-01)
      The Spot 42 RNA is a 109 nucleotide long (in Escherichia coli) noncoding small regulatory RNA (sRNA) encoded by the spf (spot fourty-two) gene. spf is found in gamma-proteobacteria and the majority of experimental work on Spot 42 RNA has been performed using E. coli, and recently Aliivibrio salmonicida. In the cell Spot 42 RNA plays essential roles as a regulator in carbohydrate metabolism and uptake, ...
    • Stable Platinum(IV) Corroles: Synthesis, Molecular Structure, and Room-Temperature Near-IR Phosphorescence 

      Alemayehu, Abraham; McCormick, Laura J; Gagnon, Kevin J.; Borisov, Sergey M.; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-08-17)
      A series of stable Pt(IV) corrole complexes with the general formula Pt<sup>IV</sup>[TpXPC](<i>m/p</i>-C<sub>6</sub>H<sub>4</sub>CN)(py), where TpXPC<sup>3–</sup> is the trianion of a tris(<i>p</i>-X-phenyl)corrole and X = CF<sub>3</sub>, H, and CH<sub>3</sub>, has been synthesized, affording key physicochemical data on a rare and elusive class of metallocorroles. Single-crystal X-ray structures of ...
    • Stepwise Deoxygenation of Nitrite as a Route to Two Families of Ruthenium Corroles: Group 8 Periodic Trends and Relativistic Effects 

      Alemayehu, Abraham; Vazquez Lima, Hugo; Gagnon, Kevin J.; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-04-19)
      Given the many applications of ruthenium porphyrins, the rarity of ruthenium corroles and the underdeveloped state of their chemistry are clearly indicative of an area ripe for significant breakthroughs. The tendency of ruthenium corroles to form unreactive metal–metal-bonded dimers has been recognized as a key impediment in this area. Herein, by exposing free-base meso-tris(p-X-phenyl)corroles, ...
    • Structural and biochemical characterization of VIM-26 shows that Leu224 has implications for the substrate specificity of VIM metallo-β-lactamases 

      Leiros, Hanna-Kirsti S.; Edvardsen, Kine Susann Waade; Bjerga, Gro Elin Kjæreng; Samuelsen, Ørjan (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-02-06)
      During the last decades antimicrobial resistance has become a global health problem. Metallo-β-lactamases (MBLs) which are broad-spectrum β-lactamases that inactivate virtually all β-lactams including carbapenems, are contributing to this health problem. In this study a novel MBL variant, termed VIM-26, identified in a Klebsiella pneumoniae isolate was studied. VIM-26 belongs to the Verona ...
    • Structural and thermodynamic insight into phenylalanine hydroxylase from the human pathogen Legionella pneumophila 

      Leiros, Hanna-Kirsti S.; Flydal, Marte Innselset; Martinez, Aurora (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      Phenylalanine hydroxylase from Legionella pneumophila (lpPAH) has a major functional role in the synthesis of the pigment pyomelanin, which is a potential virulence factor. We present here the crystal structure of lpPAH, which is a dimeric enzyme that shows high thermostability, with a midpoint denat- uration temperature of 79 ◦C, and low substrate affinity. The structure revealed a dimerization ...
    • Structural insight into a CE15 esterase from the marine bacterial metagenome 

      De Santi, Concetta; Gani, Osman A. B. S. M.; Helland, Ronny; Williamson, Adele Kim (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-12-08)
      The family 15 carbohydrate esterase (CE15) MZ0003, which derives from a marine Arctic metagenome, has a broader substrate scope than other members of this family. Here we report the crystal structure of MZ0003, which reveals that residues comprising the catalytic triad differ from previously-characterized fungal homologs, and resolves three large loop regions that are unique to this bacterial ...
    • Structural insights into TMB-1 and the role of residues 119 and 228 in substrate and inhibitor binding 

      Skagseth, Susann; Christopeit, Tony; Akhter, Sundus; Bayer, Annette; Samuelsen, Ørjan; Leiros, Hanna-Kirsti S. (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-05-30)
      Metallo-β-lactamases (MBLs) threaten the effectiveness of β-lactam antibiotics, including carbapenems, and are a concern for global public health. β-Lactam/β-lactamase inhibitor combinations active against class A and class D carbapenemases are used, but no clinically useful MBL inhibitor is currently available. Tripoli metallo-β-lactamase-1 (TMB-1) and TMB-2 are members of MBL subclass B1a, where ...
    • Structural intermediates of a DNA-ligase complex illuminate the role of the catalytic metal ion and mechanism of phosphodiester bond formation 

      Williamson, Adele Kim; Leiros, Hanna-Kirsti S. (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-07-17)
      DNA ligases join adjacent 5′ phosphate (5′P) and 3′ hydroxyl (3′OH) termini of double-stranded DNA via a three-step mechanism requiring a nucleotide cofactor and divalent metal ion. Although considerable structural detail is available for the first two steps, less is known about step 3 where the DNA-backbone is joined or about the cation role at this step. We have captured high-resolution structures ...
    • Structure and function of a CE4 deacetylase isolated from a marine environment 

      Tuveng, Tina Rise; Rothweiler, Ulli; Udatha, D.B.R.K. Gupta; Vaaje-Kolstad, Gustav; Smalås, Arne O.; Eijsink, Vincent (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-11-06)
      Chitin, a polymer of β(1–4)-linked N-acetylglucosamine found in e.g. arthropods, is a valuable resource that may be used to produce chitosan and chitooligosaccharides, two compounds with considerable industrial and biomedical potential. Deacetylating enzymes may be used to tailor the properties of chitin and its derived products. Here, we describe a novel CE4 enzyme originating from a marine ...
    • Structure determination of uracil-DNA N-glycosylase from Deinococcus radiodurans in complex with DNA 

      Pedersen, Hege Lynum; Johnson, Kenneth; McVey, Colin; Leiros, Ingar; Moe, Elin (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-10-01)
    • The structure of a dual-specificity tyrosine phosphorylation-regulated kinase 1A-PKC412 complex reveals disulfide-bridge formation with the anomalous catalytic loop HRD(HCD) cysteine 

      Alexeeva, Marina; Åberg, espen; Engh, Richard Alan; Rothweiler, Ulli (Journal article; Tidsskriftartikkel; Peer reviewed, 2015)
      Dual-specificity tyrosine phosphorylation-regulated kinase 1A (DYRK1A) is a protein kinase associated with neuronal development and brain physiology. The DYRK kinases are very unusual with respect to the sequence of the catalytic loop, in which the otherwise highly conserved arginine of the HRD motif is replaced by a cysteine. This replacement, along with the proximity of a potential disulfide-bridge ...
    • The structure of the metallo-β-lactamase VIM-2 in complex with a triazolylthioacetamide inhibitor 

      Christopeit, Tony; Yang, Ke-Wu; Yang, Shao-Kang; Leiros, Hanna-Kirsti S. (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-11)
      The increasing number of pathogens expressing metallo-β-lactamases (MBLs), and in this way achieving resistance to β-lactam antibiotics, is a significant threat to global public health. A promising strategy to treat such resistant pathogens is the co-administration of MBL inhibitors together with β-lactam antibiotics. However, an MBL inhibitor suitable for clinical use has not yet been identified. ...
    • Structure, activity and thermostability investigations of OXA-163, OXA-181 and OXA-245 using biochemical analysis, crystal structures and differential scanning calorimetry analysis 

      Lund, Bjarte Aarmo; Thomassen, Ane Molden; Carlsen, Trine Josefine Olsen; Leiros, Hanna-Kirsti S. (Journal article; Tidsskriftartikkel; Peer reviewed, 2017)
      The first crystal structures of the class D β-lactamases OXA-181 and OXA-245 were determined to 2.05 and 2.20 Å resolution, respectively; in addition, the structure of a new crystal form of OXA-163 was resolved to 2.07 Å resolution. All of these enzymes are OXA-48-like and have been isolated from different clinical Klebsiella pneumoniae strains and also from other human pathogens such as Pseudomonas ...
    • Structure, solvent, and relativistic effects on the NMR chemical shifts in square-planar transition-metal complexes: Assessment of DFT approaches 

      Vicha, Jan; Novotny, Jan; Straka, Michal; Repisky, Michal; Ruud, Kenneth; Komorovsky, Stanislav; Marek, Radek (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-08-25)
      The role of various factors (structure, solvent, and relativistic treatment) was evaluated for square-planar 4d and 5d transition-metal complexes. The DFT method for calculating the structures was calibrated using a cluster approach and compared to X-ray geometries, with the PBE0 functional (def2-TZVPP basis set) providing the best results, followed closely by the hybrid TPSSH and the MN12SX ...
    • A Synergy of Artificial Bee Colony and Genetic Algorithms to Determine the Parameters of the Σ-Gram Distance 

      Muhammad Fuad, Muhammad Marwan (Journal article; Tidsskriftartikkel; Peer reviewed, 2014)
      In a previous work we presented the Σ-gram distance that computes the similarity between two sequences. This distance includes parameters that we calculated by means of an optimization process using artificial bee colony. In another work we showed how population-based bio-inspired algorithms can be sped up by applying a method that utilizes a pre-initialization stage to yield an optimal initial ...
    • Synthesis and Molecular Structure of a Copper Octaiodocorrole 

      Thomassen, Ivar Kristian; McCormick, Laura J.; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-05-09)
      Although rather delicate on account of their propensity to undergo deiodination, β-octaiodoporphyrinoids are of considerable interest as potential precursors to novel β-octasubstituted macrocycles. Presented herein are early results of our efforts to synthesize β-octaiodocorrole derivatives. Oxidative condensation of 3,4-diiodopyrrole and aromatic aldehydes failed to yield free-base octaiodocorroles. ...
    • Synthesis of Indoles and Pyrroles Utilizing Iridium Carbenes Generated from Sulfoxonium Ylides 

      Vaitla, Janakiram; Bayer, Annette; Hopmann, Kathrin Helen (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-03-20)
      Metal carbenes can undergo a myriad of synthetic transformations. Sulfur ylides are potential safe precursors of metal carbenes. Herein, we report cascade reactions that involve carbenoids derived from sulfoxonium ylides for the efficient and regioselective synthesis of indoles and pyrroles. The tandem action of iridium and Brønsted acid catalysts enables rapid assembly of the heterocycles from ...
    • Synthetic cationic antimicrobial peptides bind with their hydrophobic parts to drug site II of human serum albumin 

      Sivertsen, Annfrid; Isaksson, Johan; Leiros, Hanna-Kirsti S.; Svenson, Johan; Svendsen, John Sigurd; Brandsdal, Bjørn Olav (Journal article; Tidsskriftartikkel; Peer reviewed, 2014)