O uso da língua como fator para a (re)afirmação da identidade étnica: experiências em Colônia Witmarsum

Holm, Carla Caroline; Cardozo, Poliana Fabí­ula

doi:10.24933/horizontes.v33i2.164

Cited by 3 publications

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“…Elaborate biosynthetic pathways are responsible for assembling Fe-S clusters and delivering the appropriate cluster form to clientele proteins. Although there are decades of excellent studies of the self-assembly of Fe-S clusters and the associated enzymatic process, 49,50 key mechanistic questions remain. Here, we implemented high-resolution time-dependent native MS experiments to define intermediates and provide insight into the assembly of Fe-S clusters for the bacterial ISC biosynthetic system.…”

Section: Discussionmentioning

confidence: 99%

Molecular Mechanism of ISC Iron–Sulfur Cluster Biogenesis Revealed by High-Resolution Native Mass Spectrometry

et al. 2020

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Iron−sulfur (Fe−S) clusters are ubiquitous protein cofactors that are required for many important biological processes including oxidative respiration, nitrogen fixation, and photosynthesis. Biosynthetic pathways assemble Fe-S clusters with different iron-to-sulfur stoichiometries and distribute these clusters to appropriate apoproteins. In the ISC pathway, the pyridoxal 5′phosphate-dependent cysteine desulfurase enzyme IscS provides sulfur to the scaffold protein IscU, which templates the Fe-S cluster assembly. Despite their functional importance, mechanistic details for cluster synthesis have remained elusive. Recent advances in native mass spectrometry (MS) have allowed proteins to be preserved in native-like structures and support applications in the investigation of protein structure, dynamics, ligand interactions, and the identification of proteinassociated intermediates. Here, we prepared samples under anaerobic conditions and then applied native MS to investigate the molecular mechanism for Fe-S cluster synthesis. This approach was validated by the high agreement between native MS and traditional visible circular dichroism spectroscopic assays. Time-dependent native MS experiments revealed potential iron-and sulfurbased intermediates that decay as the [2Fe-2S] cluster signal developed. Additional experiments establish that (i) Zn(II) binding stabilizes IscU and protects the cysteine residues from oxidation, weakens the interactions between IscU and IscS, and inhibits Fe-S cluster biosynthesis; and (ii) Fe(II) ions bind to the IscU active site cysteine residues and another lower affinity binding site and promote the intermolecular sulfur transfer reaction from IscS to IscU. Overall, these results

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Section: Discussionmentioning

confidence: 99%

Molecular Mechanism of ISC Iron–Sulfur Cluster Biogenesis Revealed by High-Resolution Native Mass Spectrometry

et al. 2020

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“…Prominent examples of this strategy include the nitrogenase and CO dehydrogenase enzymes (see Figure 7, right). [76][77][78][79] While in the case of Fe(TPB) a very low formal oxidation state at Fe must be reached in order for the borane to adopt this special role, tuning of M→LA interactions potentially provides a route to small molecule activation under milder conditions.…”

Section: Discussionmentioning

confidence: 99%

Exploring the Limits of Dative Boratrane Bonding: Iron as a Strong Lewis Base in Low-Valent Non-Heme Iron-Nitrosyl Complexes

et al. 2020

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We previously reported the synthesis and preliminary characterization of a unique series of lowspin (ls) {FeNO} 8−10 complexes supported by an ambiphilic trisphosphineborane ligand, [Fe(TPB)(NO)] +/0/− . Herein, we use advanced spectroscopic techniques and density functional theory (DFT) calculations to extract detailed information as to how the bonding changes across the redox series. We find that, despite the highly reduced nature of these complexes, they feature an NO + ligand throughout with strong Fe-NO π-backbonding and essentially closed-shell electronic structures of their FeNO units. This is enabled by an Fe-B interaction that is present throughout the series. In particular, the most reduced [Fe(TPB)(NO)] − complex, an example of a ls-{FeNO} 10 species, features a true reverse dative Fe→B bond where the Fe center acts as a strong Lewis-base. Hence, this complex is in fact electronically similar to the ls-{FeNO} 8 system, with two additional electrons "stored" on site in an Fe-B single bond. The outlier in this series is the ls-{FeNO} 9 complex, due to spin polarization (quantified by pulse EPR spectroscopy), which weakens the Fe-NO bond. These data are further contextualized by comparison with a related N 2 complex, [Fe(TPB)(N 2 )] − , which is a key intermediate in Fe(TPB)-catalyzed N 2 fixation. Our present study finds that the Fe→B interaction is key for storing the electrons needed to achieve a highly reduced state in these systems, and highlights the pitfalls associated with using geometric parameters to try to evaluate reverse dative interactions, a finding with broader implications to the study of transition metal complexes with boratrane and related ligands.

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“…01). Este assentamento foi formado em 1951 (Holm e Cardozo, 2015), por Menonitas que remigraram da cidade homônima, no estado de Santa Catarina, "em busca de melhores condições de solo para agricultura e para o livre exercício da sua religiosidade" (Holm et al, 2017: 459). Surgido da reforma protestante no início dos anos 1500, e com origem na região da Frísia, situada ao norte dos atuais territórios da Alemanha e da Holanda, este grupo étnico-religioso luta, desde então, pela dissociação das leis do Estado das normas da Igreja Católica (Holm, 2015).…”

Section: Considerações Iniciaisunclassified

Leitura teórica de proposta projetual: ensaio sobre a Colônia Witmarsum, Palmeira, Paraná, Brasil

Hardt¹,

Hardt²,

Hardt³

2020

XII Seminario Internacional De Investigación en Urbanismo, São Paulo-Lisboa, 2020

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Perante o potencial distanciamento entre teoria e prática em projetos urbanos, o objetivo do trabalho consiste em associar postulados teóricos a soluções projetuais, adotando, como estudo de caso, a intervenção idealizada para a Colônia Witmarsum. Com abordagem qualitativa, natureza aplicada e enfoque experimental, o ensaio partiu da compreensão da problemática da gênese espacial. Esse diagnóstico contextual evidencia tanto a subtração pelo deslocamento incitado de Menonitas e a divisão de seus membros em vários países, quanto a multiplicação pela consolidação comunitária, a adição pelo trabalho conjunto e a igualdade pelo cooperativismo. A leitura do prognóstico propositivo identifica que a apropriação desses sinais matemáticos como linguagem de desenho valoriza a identidade cultural e aponta para a transformação do espaço em território, pelo domínio da coletividade, e deste último em lugar, pelo estímulo ao pertencimento, com acentuação do processo perceptual da paisagem.

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O uso da língua como fator para a (re)afirmação da identidade étnica: experiências em Colônia Witmarsum

Cited by 3 publications

References 0 publications

Molecular Mechanism of ISC Iron–Sulfur Cluster Biogenesis Revealed by High-Resolution Native Mass Spectrometry

Molecular Mechanism of ISC Iron–Sulfur Cluster Biogenesis Revealed by High-Resolution Native Mass Spectrometry

Exploring the Limits of Dative Boratrane Bonding: Iron as a Strong Lewis Base in Low-Valent Non-Heme Iron-Nitrosyl Complexes

Leitura teórica de proposta projetual: ensaio sobre a Colônia Witmarsum, Palmeira, Paraná, Brasil

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