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1.
J Inorg Biochem ; 254: 112503, 2024 05.
Artigo em Inglês | MEDLINE | ID: mdl-38364337

RESUMO

Anthropogenic activities in agriculture and health use the antimicrobial properties of copper. This has led to copper accumulation in the environment and contributed to the emergence of copper resistant microorganisms. Understanding bacterial copper homeostasis diversity is therefore highly relevant since it could provide valuable targets for novel antimicrobial treatments. The periplasmic CopI protein is a monodomain cupredoxin comprising several copper binding sites and is directly involved in copper resistance in bacteria. However, its structure and mechanism of action are yet to be determined. To study the different binding sites for cupric and cuprous ions and to understand their possible interactions, we have used mutants of the putative copper binding modules of CopI and spectroscopic methods to characterize their properties. We show that CopI is able to bind a cuprous ion in its central histidine/methionine-rich region and oxidize it thanks to its cupredoxin center. The resulting cupric ion can bind to a third site at the N-terminus of the protein. Nuclear magnetic resonance spectroscopy revealed that the central histidine/methionine-rich region exhibits a dynamic behavior and interacts with the cupredoxin binding region. CopI is therefore likely to participate in copper resistance by detoxifying the cuprous ions from the periplasm.


Assuntos
Anti-Infecciosos , Azurina , Cobre , Cobre/química , Histidina/química , Sítios de Ligação , Metionina , Íons
2.
Chem Commun (Camb) ; 56(68): 9850-9853, 2020 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-32716419

RESUMO

By combining X-ray crystallography, electron paramagnetic resonance techniques and density functional theory-based modelling, we provide evidence for a direct coordination of the product analogue, phosphate, to the molybdenum active site of a sulfite dehydrogenase. This interaction is mimicking the still experimentally uncharacterized reaction intermediate proposed to arise during the catalytic cycle of this class of enzymes. This work opens new perspectives for further deciphering the reaction mechanism of this nearly ubiquitous class of oxidoreductases.


Assuntos
Molibdênio/química , Fosfatos/química , Sulfito Desidrogenase/química , Domínio Catalítico , Cristalografia por Raios X , Teoria da Densidade Funcional , Espectroscopia de Ressonância de Spin Eletrônica , Ligação de Hidrogênio , Sulfito Desidrogenase/metabolismo , Thermus/enzimologia
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