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Target Analogue Imprinted Polymers with Affinity for Folic Acid and Related Compounds
2001
Two approaches to synthesize molecularly imprinted polymers with affinity for folic acid and other substituted pteridines have been compared. In the first approach, the folic acid analogue methotrexate was used as template and functional monomers capable of generating selective binding sites were searched in a miniaturized screening system based on binding assessment in the batch mode. Highest selectivity was seen using 2-vinylpyridine as functional monomer, which was confirmed in the chromatographic mode for a batch synthesized on a gram scale. However, the retentivity and selectivity of this phase were insufficient for anticipated applications. In a second approach, using methacrylic acid…
Structural and functional models for the dinuclear copper active site in catechol oxidases
2003
Two new mu-methoxo-bridged dinuclear copper(II) complexes with a N-substituted sulfonamide, [Cu(mu-OMe)(L)(NH(3))](2) (1) and [Cu(mu-OMe)(L)(DMSO)](2) (2) [HL, N-2-(4-methylbenzothiazole)benzenesulfonamide], have been prepared and characterized by single-crystal X-ray difraction analyses. Compound 1 crystallizes in the monoclinic space group C(2)/c with a=22.0678(18), b=7.9134(7), c=21.1186(18)A, beta=113.788(4) degrees and Z=8. Compound 2 crystallizes in the monoclinic space group C(2)/c with a=18.0900(10), b=9.5720(10), c=24.2620(10) A, beta=98.7120(10) degrees and Z=8. In both complexes the copper atoms have square-planar environments bridged by two oxygen atoms from methoxide groups. Ma…
A three-dimensional model of mammalian tyrosinase active site accounting for loss of function mutations
2007
Tyrosinases are the first and rate-limiting enzymes in the synthesis of melanin pigments responsible for colouring hair, skin and eyes. Mutation of tyrosinases often decreases melanin production resulting in albinism, but the effects are not always understood at the molecular level. Homology modelling of mouse tyrosinase based on recently published crystal structures of non-mammalian tyrosinases provides an active site model accounting for loss-of-function mutations. According to the model, the copper-binding histidines are located in a helix bundle comprising four densely packed helices. A loop containing residues M374, S375 and V377 connects the CuA and CuB centres, with the peptide oxyge…
Ein Bindungsstellenmodell für H2-Antagonisten vom 4-Pyrimidinon-Typ
1985
In einer Reihe von 17 Histamin-H2-antagonistisch wirksamen 5-substituierten 4-Pyrimidinonen wird durch Berechnung von Wechselwirkungsenergien ein Modell fur die Rezeptorbindungsstelle des Substituenten am C-5 des Pyrimidinons vorgeschlagen. Als Bindungsstelle fungiert die Aminosaure Arginin. A Binding Site Model for H2-Receptor Antagonists of the 4-Pyrimidone Type Based on calculations of the energies of interaction for a series of seventeen 5-substituted 4-pyrimidones with H2-antagonistic activity, a receptor binding site model for substituents at C-5 of the pyrimidone ring is proposed. The binding site is modeled using the amino acid arginine.
Light Regulation of the Thylakoid LHCII Protein Phosphorylation at the Substrate Level
1998
The distribution of light energy between the two photosystems as well as the light-induced turnover of PSII proteins are regulated by the reversible phosphorylation of LHCII and the PSII-core proteins. The thylakoid protein kinase(s) is activated by a signal transduction system involving the interaction of reduced plastoquinone with the quinol oxidation site of the cytochrome bf complex [1]. Phosphorylation of the mobile pool of LHCII induces dissociation of this antenna from PSII and allows its interaction with the PSI in the stroma exposed membranes (state transition)[21. Dephosphorylation of LHCII by a membrane -bound phosphatase appears to be regulated by a cyclophilinlike protein locat…
Bleomycin, an Antibiotic That Removes Thymine from Double-Stranded DNA
1977
Publisher Summary This chapter reviews that bleomycins are members of a new class of DNA-modifying agents, the quasi-enzymes. In in vitro systems, bleomycin first removes thymines from native DNA by hydrolysis of the N-glycosidic bonds without modifying the deoxyribose moiety. In a second step, single-strand scissions occur at the sites of the nonglycosidic deoxyribose moieties, resulting in the formation of 3'-OH and 5'-P termini. It is suggested that bleomycin is bound to DNA by interaction of the positively charged terminal amine moiety with the negatively charged phosphate group in DNA; intercalation seems to be involved in binding. Bleomycin is inactivated by copper and zinc ions, prob…
ElaC Encodes a Novel Binuclear Zinc Phosphodiesterase
2002
ElaC is a widespread gene found in eubacteria, archaebacteria, and mammals with a highly conserved sequence. Two human ElaC variants were recently associated with cancer (Tavtigian, S. V., Simard, J., Teng, D. H., Abtin, V., Baumgard, M., Beck, A., Camp, N. J., Carillo, A. R., Chen, Y., Dayananth, P., Desrochers, M., Dumont, M., Farnham, J. M., Frank, D., Frye, C., Ghaffari, S., Gupte, J. S., Hu, R., Iliev, D., Janecki, T., Kort, E. N., Laity, K. E., Leavitt, A., Leblanc, G., McArthur-Morrison, J., Pederson, A., Penn, B., Peterson, K. T., Reid, J. E., Richards, S., Schroeder, M., Smith, R., Snyder, S. C., Swedlund, B., Swensen, J., Thomas, A., Tranchant, M., Woodland, A. M., Labrie, F., Sko…
Pamięci nieukojone. Wokół upamiętniania ofiar w Serbii i Chorwacji (Jasenovac, Bleiburg, belgradzkie Sajmište)
2016
Tekst koncentruje się na przemianach tożsamości narodowych w dwóch krajach postjugosłowiańskich (Serbii i Chorwacji). (Re)konstrukcje przeszłości mające tam miejsce od lat dziewięćdziesiątych XX wieku zakładały przede wszystkim zanegowanie dziedzictwa wspólnego opartego na zmitologizowanej walce partyzanckiej, a następnie wybór z przeszłości tych wydarzeń, o których pamięć należy kultywować. Walka przeciwstawnych pamięci (serbskiej i chorwackiej) oraz polaryzacja społeczeństwa chorwackiego pokazana zostaje na przykładzie praktyk komemoratywnych związanych z miejscami zagłady (Jasenovac i Bleiburg) z okresu drugiej wojny światowej. W tekście przywołano również miejsce kojarzone z Holokaustem…
Exciton and multiexciton optical properties of single InAs/GaAs site-controlled quantum dots
2013
We have studied the optical properties of InAs site-controlled quantum dots (SCQDs) grown on pre-patterned GaAs substrates. Since InAs nucleates preferentially on the lithography motifs, the location of the resulting QDs is determined by the pattern, which is fabricated by local oxidation nanolithography. Optical characterization has been performed on such SCQDs to study the fundamental and excited states. At the ground state different exciton complex transitions of about 500 μeV linewidth have been identified and the fine structure splitting of the neutral exciton has been determined (≈65 μeV). The observed electronic structure covers the demands of future quantum information technologies.…
PROTEGGERE E VALORIZZARE: RIFLESSIONI PER UNA BUONA PRATICA SUI SITI ARCHEOLOGICI
2014
Tra i beni culturali quelli archeologici hanno più animato il dibattito culturale sul rapporto fra conservazione e valorizzazione. La fragilità con cui la materia ci viene consegnata dalla storia, la frammentarietà del reperto, la scarsa disponibilità di risorse finanziarie, in relazione anche alla vastità del patrimonio a noi pervenuto, impongono interventi mirati e talvolta urgenti per la salvaguardia e la conservazione di tali beni. Ma la sola conservazione non può costituire l’obiettivo ultimo dell’intervento: essa deve interessare anche azioni di messa in valore, di fruizione e di comunicazione, necessarie per favorire un nuovo ruolo a queste realtà private dell’originaria identità. Qu…