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2001
Branco, LC, Afonso CAM.  2001.  Ionic liquids as recyclable reaction media for the tetrahydropyranylation of alcohols. Tetrahedron. 57:4405-4410., Number 20 AbstractWebsite
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Pina, F, Melo MJ, Alves S, Ballardini R, Maestri M, Passaniti P.  2001.  Micelle effect on ground and excited state proton transfer reactions involving the 4-methyl-7-hydroxyflavylium cation. New Journal of Chemistry. 25:747-752., Number 5 AbstractWebsite
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Pereira, AS, Tavares P, Moura I, Moura JJG, Huynh BH.  2001.  Mossbauer characterization of the iron-sulfur clusters in Desulfovibrio vulgaris hydrogenase. Journal Of The American Chemical Society. {123}:{2771-2782}., Number {12} Abstract

The periplasmic hydrogenase of Desulfovibrio vulgaris (Hildenbourough) is an all Fe-containing hydrogenase. It contains two ferredoxin type [4Fe-4S] clusters, termed the F clusters, and a catalytic H cluster. Recent X-ray crystallographic studies on two Fe hydrogenases revealed that the H cluster is composed of two sub-clusters, a [4Fe-4S] cluster ([4Fe-4S]H) and-a binuclear Fe cluster ([2Fe]H), bridged by a cysteine sulfur. The aerobically purified D. vulgaris hydrogenase is stable in air. It is inactive and requires reductive activation. Upon reduction, the enzyme becomes sensitive to O(2) indicating that the reductive activation process is irreversible. Previous EPR investigations showed that upon reoxidation (under argon) the H cluster exhibits a rhombic EPR signal that is not seen in the as-purified enzyme, suggesting a conformational change in association with the reductive activation. For the purpose of gaining more information on the electronic properties of this unique H cluster and to understand further the reductive activation process, variable-temperature and variable-field Mossbauer spectroscopy has been used to characterize the Fe-S clusters in D. vulgaris hydrogenase poised at different redox states generated during a reductive titration, and in the GO-reacted enzyme. The data were successfully decomposed into spectral components corresponding to the F and H clusters,and characteristic parameters describing the electronic and magnetic properties of the F and H clusters were obtained. Consistent with the X-ray crystallographic results, the spectra of the H cluster can be understood as originating from an exchange coupled [4Fe-4S] - [2Fe] system. In particular, detailed analysis of the data reveals that the reductive activation begins with reduction of the [4Fe-4S]H cluster from the 2+ to the If state, followed by transfer of the reducing equivalent from the [4Fe-4S]H subcluster to the binuclear [2Fe]H subcluster. The results also reveal that binding of exogenous CO to the H cluster affects significantly the exchange coupling between the [4Fe-4S]H and the [2Fe]H subclusters. Implication of such a CO binding effect is discussed.

Alves, S, Pina F, Albelda MT, Garcia-Espana E, Soriano C, Luis SV.  2001.  Open-chain polyamine ligands bearing an anthracene unit - Chemosensors for logic operations at the molecular level. European Journal of Inorganic Chemistry. :405-412., Number 2 AbstractWebsite
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Antunes, AMM, Marto SJL, Branco PS, Prabhakar S, Lobo AM.  2001.  Palladium(II)-promoted aziridination of olefins with bromamine T as the nitrogen transfer reagent. CHEMICAL COMMUNICATIONS. :405-406., Number 5 Abstract
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Bencini, A, Bianchi A, Giorgi C, Romagnoli E, Lodeiro C, Saint-Maurice A, Pina F, Valtancoli B.  2001.  Photochemical- and pH-switching properties of a new photoelastic ligand based upon azobenzene. Basicity and anion binding. Supramolecular Chemistry. 13:277-285., Number 2 AbstractWebsite
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Costa, SMB, Lopez-Cornejo P, Togashi DM, Laia CAT.  2001.  Photoinduced electron transfer in non-aqueous microemulsions. Journal of Photochemistry and Photobiology a-Chemistry. 142:151-161., Number 2-3 AbstractWebsite
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Bernardo, MA, Alves S, Pina F, de Melo JS, Albelda MT, Garcia-Espana E, Llinares JM, Soriano C, Luis SV.  2001.  Polyamine linear chains bearing two identical terminal aromatic units. Evidence for a photo induced bending movement. Supramolecular Chemistry. 13:435-445., Number 3 AbstractWebsite
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Albelda, MT, Bernardo MA, Diaz P, Garcia-Espana E, de Melo JS, Pina F, Soriano C, Santiago VLE.  2001.  Polyamines containing naphthyl groups as pH-regulated molecular machines driven by light. Chemical Communications. :1520-1521., Number 16 AbstractWebsite
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Almeida, G, Rodrigues C, Lampreia J.  2001.  Proteómica: a Interface entre a Biologia Molecular e a Biochemistry de Proteínas. Bol. Soc. Port. Química. 82:49-56. Abstract
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Carvalho, AL, Dias JM, Sanz L, Romero A, Calvete JJ, Romao MJ.  2001.  Purification, crystallization and identification by X-ray analysis of a prostate kallikrein from horse seminal plasma. Acta Crystallographica Section D-Biological Crystallography. 57:1180-1183. AbstractWebsite
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Baldwin, J, Voegtli WC, Khidekel N, Moenne-Loccoz P, Krebs C, Pereira AS, Ley BA, Huynh BH, Loehr TM, Riggs-Gelasco PJ, Rosenzweig AC, Bollinger JM.  2001.  Rational reprogramming of the R2 subunit of Escherichia coli ribonucleotide reductase into a self-hydroxylating monooxygenase. Journal Of The American Chemical Society. {123}:{7017-7030}., Number {29}, 1155 16TH ST, NW, WASHINGTON, DC 20036 USA: AMER CHEMICAL SOC Abstract

The outcome of O-2 activation at the diiron(II) cluster in the R2 subunit of Escherichia coli (class I) ribonucleotide reductase has been rationally altered from the normal tyrosyl radical (Y122)(1) production to self-hydroxylation of a phenylalanine side-chain by two amino acid substitutions that leave intact the (histidine)(2)-(carboxylate)(4) ligand set characteristic of the diiron-carboxylate family. Iron ligand Asp (D) 84 was replaced with Glu (E), the amino acid found in the cognate position of the structurally similar diiron-carboxylate protein, methane monooxygenase hydroxylase (MMOH). We previously showed that this substitution allows accumulation of a mu -1,2-peroxodiiron(III) intermediate,(2 3) which does not accumulate in the wild-type (wt) protein and is probably a structural homologue of intermediate P (H-peroxo) in O-2 activation by MMOH.(4) In addition, the near-surface residue Trp (W) 48 was replaced with Phe (F), blocking transfer of the ``extra'' electron that occurs in wt R2 during formation of the formally Fe(LII)Fe(IV) cluster X.(5-7) Decay of the mu1,2-peroxodiiron(III) complex in R2-W38F/D84E gives an initial brown product, which contains very little YI22(.) and which converts very slowly (t(1/2) similar to 7 h) upon incubation at 0 degreesC to an intensely purple final product. X-ray crystallographic analysis of the purple product indicates that F208 has undergone epsilon -hydroxylation and the resulting phenol has shifted significantly to become st ligand to Fe2 of the diiron cluster. Resonance Raman (RR) spectra of the purple product generated with O-16(2) or O-18(2) show appropriate isotopic sensitivity in bands assigned to O-phenyl and Fe-O-phenyl vibrational modes, confirming that the oxygen of the Fe(III)-phenolate species is derived from Or. Chemical analysis, experiments involving interception of the hydroxylating intermediate with exogenous reductant, and Mossbauer and EXAFS characterization of the brown and purple species establish that F208 hydroxylation occurs during decay of the peroxo complex and formation of the initial brown product. The slow transition to the purple Fe(LII)-phenolate species is ascribed to a ligand rearrangement in which mu -O2- is lost and the F208-derived phenolate coordinates. The reprogramming to F208 monooxygenase requires both amino acid substitutions, as very little epsilon -hydroxyphenylalanine is formed and pathways leading to Y122(.) formation predominate in both R2-D84E and R2-W48F(2-7).

Laia, CAT, Costa SMB.  2001.  Solvatochromism and thermochromism of the electronic spectra of an indocarbocyanine dye. Journal of Molecular Structure. 565:83-86. AbstractWebsite
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Goncalves, LML, Cunha C, Almeida G, Macieira S, Costa C, Lampreia J, Romao MJ, Moura JJG, Moura I.  2001.  Structural studies on Desulfovibrio desulfuricans ATCC 27774 multiheme nitrite reductase - characterization of the subunits. Journal of Inorganic Biochemistry. 86:316-316., Number 1 AbstractWebsite
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Rebelo, JM, Dias JM, Huber R, Moura JJG, Romao MJ.  2001.  Structure refinement of the aldehyde oxidoreductase from Desulfovibrio gigas (MOP) at 1.28 angstrom. Journal of Biological Inorganic Chemistry. 6:791-800., Number 8 AbstractWebsite
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Franco, R, Pereira AS, Tavares P, Mangravita A, Barber MJ, Moura I, Ferreira GC.  2001.  Substitution of murine ferrochelatase glutamate-287 with glutamine or alanine leads to porphyrin substrate-bound variants. BIOCHEMICAL JOURNAL. {356}:{217-222}., Number {1} Abstract

Ferrochelatase (EC 4.99.1.1) is the terminal enzyme of the haem biosynthetic pathway and catalyses iron chelation into the protoporphyrin IX ring. Glutamate-287 (E287) of murine mature ferrochelatase is a conserved residue in all known sequences of ferrochelatase, is present at the active site of the enzyme, as inferred from the Bacillus subtilis ferrochelatase three-dimensional structure, and is critical for enzyme activity. Substitution of E287 with either glutamine (Q) or alanine (A) yielded variants with lower enzymic activity than that of the wild-type ferrochelatase and with different absorption spectra from the wild-type enzyme. In contrast to the wild-type enzyme, the absorption spectra of the variants indicate that these enzymes, as purified, contain protoporphyrin IX. Identification and quantification of the porphyrin bound to the E287-directed variants indicate that approx. 80% of the total porphyrin corresponds to protoporphyrin IX. Significantly, rapid stopped-flow experiments of the E287A and E287Q Variants demonstrate that reaction with Zn2+ results in the formation of bound Zn-protoporphyrin IX, indicating that the endogenously bound protoporphyrin IX can be used as a substrate. Taken together, these findings suggest that the structural strain imposed by ferrochelatase on the porphyrin substrate as a critical step in the enzyme catalytic mechanism is also accomplished by the E287A and E287Q variants, but without the release of the product. Thus E287 in murine ferrochelatase appears to be critical For the catalytic process by controlling the release of the product.

Batista, AG, Rodrigues JM, Ortigueira MD.  2001.  Time-Frequency and Time-Scale Characterisation of the Beat-by-Beat High-Resolution Electrocardiogram. Sixth Portuguese Conference on Biomedical Engineering Proceedings. Abstract
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Raaijmakers, H, Teixeira S, Dias JM, Almendra MJ, Brondino CD, Moura I, Moura JJG, Romao MJ.  2001.  Tungsten-containing formats dehydrogenase from Desulfovibrio gigas: metal identification and preliminary structural data by multi-wavelength crystallography. Journal of Biological Inorganic Chemistry. 6:398-404., Number 4 AbstractWebsite
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Moniz, A.  2001.  {A cooperação entre equipas de trabalho em empresas em rede: vantagens para o desenvolvimento regional[Workteam Co-operation in Networked Companies: regional development advantages]}. , Number 5920: University Library of Munich, Germany Abstract

Working teams in enterprise environment are considered as the most advanced forms of work organisation. This means the forms that can improve productivity quality of working life. Nevertheless, it prevails a slow development and dissemination of these advanced organisational forms in European companies. The reason for that lays in a complex linkage factors from social values to the economical pressures. But other factors are also related to the national systems of education training, to the different systems of industrial relations and technology policy.

Moniz, A.  2001.  {Book review of Alice R. P. Abreu (org.): Flexible production and economic governance in Latin America}. , Number http://ideas.repec.org/p/pra/mprapa/5937.html Abstract

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Moniz, A, Gomes C, Machado T, Urze P.  2001.  {Information Society, Work and the Generation of New Forms of Social Exclusion (SOWING): National Report (Portugal)}. , Number 6887: University Library of Munich, Germany Abstract

The choice over the Portuguese case studies was based on the sample constructed for the application of the firm questionnaires, during the second year of the SOWING project, 1999. This sample was fulfilled of firms among several activity sectors: textile, manufacturing, electronics, transports and software industry, based on NACE – codes (2 – digit level). Thus, we agreed to include in a new database the remaining questionnaires and construct a sample with 113 observations. Concerning the organisational change we make a distinction of three categories of change. First we analyse changes taking place at the inter-firm level (outsourcing, subcontracting, geographic relocation), followed by changes at the organisational level (deconcentration/decentralisation, reduction of hierarchical levels, introduction of cost and profit centres). The third kind of changes analysed will be those taking place at the workplace level (job enlargement/enrichment, changing character of work, work load). The Portuguese studied companies presents a relative uniform pattern considering the variables social competencies, practical knowledge, responsibility and specialized professional qualifications.

Moniz, A, Krings B, Van Hootegem G, Huys R.  2001.  {Technological practices in the European auto industry: Exploring cases from Belgium, Germany and Portugal}. , Number 5659: University Library of Munich, Germany Abstract

The relation between work organisation and technological practices in auto industry is analysed in this article. The concept of “technological practice” in this sector is used to describe the specific ways of embedding information and communication technology applications into the organizational forms and cultural patterns. This concept was developed with the Sowing project (TSER, DG XII) and that approach included either the shop floor co-operation up to the regionally based networks of companies and supporting institutions. The authors studied different sectors in the automotive firms of different European countries (Germany, Belgium and Portugal): shopfloor and production lines, design and management and the local inter-relationships. It was underlined some evidencies of the different alternatives in terms of technological practices for the same sector. Much of the litterature try to disseminate an idea of a single (and optimum) organisational model for the same type of product. And here, even with the same type of technology, and of product (medium-high range), one can find different models, different cultures, different ways of organising the industrial structure (firms, regional institutions, R&D centres) in the same sector (auto industry).

2000
Kapur, GS, Cabrita EJ, Berger S.  2000.  The qualitative probing of hydrogen bond strength by diffusion-ordered NMR spectroscopy, SEP 9 2000. Tetrahedron Letters. 41:7181-7185., Number 37 Abstract

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Wengenack, NL, Lopes H, Kennedy MJ, Tavares P, Pereira AS, Moura I, Moura JJ, Rusnak F.  2000.  Redox potential measurements of the Mycobacterium tuberculosis heme protein KatG and the isoniazid-resistant enzyme KatG(S315T): insights into isoniazid activation, Sep 19. Biochemistry. 39:11508-13., Number 37 AbstractWebsite

Mycobacterium tuberculosis KatG is a multifunctional heme enzyme responsible for activation of the antibiotic isoniazid. A KatG(S315T) point mutation is found in >50% of isoniazid-resistant clinical isolates. Since isoniazid activation is thought to involve an oxidation reaction, the redox potential of KatG was determined using cyclic voltammetry, square wave voltammetry, and spectroelectrochemical titrations. Isoniazid activation may proceed via a cytochrome P450-like mechanism. Therefore, the possibility that substrate binding by KatG leads to an increase in the heme redox potential and the possibility that KatG(S315T) confers isoniazid resistance by altering the redox potential were examined. Effects of the heme spin state on the reduction potentials of KatG and KatG(S315T) were also determined. Assessment of the Fe(3+)/Fe(2+) couple gave a midpoint potential of ca. -50 mV for both KatG and KatG(S315T). In contrast to cytochrome P450s, addition of substrate had no significant effect on either the KatG or KatG(S315T) redox potential. Conversion of the heme to a low-spin configuration resulted in a -150 to -200 mV shift of the KatG and KatG(S315T) redox potentials. These results suggest that isoniazid resistance conferred by KatG(S315T) is not mediated through changes in the heme redox potential. The redox potentials of isoniazid were also determined using cyclic and square wave voltammetry, and the results provide evidence that the ferric KatG and KatG(S315T) midpoint potentials are too low to promote isoniazid oxidation without formation of a high-valent enzyme intermediate such as compounds I and II or oxyferrous KatG.

Jovanovic, T, Ascenso C, Hazlett KR, Sikkink R, Krebs C, Litwiller R, Benson LM, Moura I, Moura JJ, Radolf JD, Huynh BH, Naylor S, Rusnak F.  2000.  Neelaredoxin, an iron-binding protein from the syphilis spirochete, Treponema pallidum, is a superoxide reductase, Sep 15. J Biol Chem. 275:28439-48., Number 37 AbstractWebsite

Treponema pallidum, the causative agent of venereal syphilis, is a microaerophilic obligate pathogen of humans. As it disseminates hematogenously and invades a wide range of tissues, T. pallidum presumably must tolerate substantial oxidative stress. Analysis of the T. pallidum genome indicates that the syphilis spirochete lacks most of the iron-binding proteins present in many other bacterial pathogens, including the oxidative defense enzymes superoxide dismutase, catalase, and peroxidase, but does possess an orthologue (TP0823) for neelaredoxin, an enzyme of hyperthermophilic and sulfate-reducing anaerobes shown to possess superoxide reductase activity. To analyze the potential role of neelaredoxin in treponemal oxidative defense, we examined the biochemical, spectroscopic, and antioxidant properties of recombinant T. pallidum neelaredoxin. Neelaredoxin was shown to be expressed in T. pallidum by reverse transcriptase-polymerase chain reaction and Western blot analysis. Recombinant neelaredoxin is a 26-kDa alpha(2) homodimer containing, on average, 0.7 iron atoms/subunit. Mossbauer and EPR analysis of the purified protein indicates that the iron atom exists as a mononuclear center in a mixture of high spin ferrous and ferric oxidation states. The fully oxidized form, obtained by the addition of K(3)(Fe(CN)(6)), exhibits an optical spectrum with absorbances at 280, 320, and 656 nm; the last feature is responsible for the protein's blue color, which disappears upon ascorbate reduction. The fully oxidized protein has a A(280)/A(656) ratio of 10.3. Enzymatic studies revealed that T. pallidum neelaredoxin is able to catalyze a redox equilibrium between superoxide and hydrogen peroxide, a result consistent with it being a superoxide reductase. This finding, the first description of a T. pallidum iron-binding protein, indicates that the syphilis spirochete copes with oxidative stress via a primitive mechanism, which, thus far, has not been described in pathogenic bacteria.

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