More on thiol switches… a novel redox mechanism regulating proteolysis in facultative anaerobes

by Thaís L. S. Araújo*

Protein homeostasis (proteostasis) is fundamental to living organisms and even if we only judge from the number and intricacies of existing mechanisms to deal with this process, one can conclude it is a priority issue for nature [1]. An intriguing problem has been to understand how facultative anaerobic bacteria adapt their proteostatic mechanisms during the transition from anaerobic to aerobic conditions. In a recent article [2,3], it was found that an interesting

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Editorial

I am very excited to present our second number of our Redoxoma Newsletter. You will soon notice why. First, we have grown bigger, indicating that this newsletter is already turning into a good vehicle for communicating ourselves around the science of redox processes. Second, we have exciting comments on scientific productions from our Redoxoma team, and I am glad to know we have even more in the pipeline. In addition, we bring selected highlights from the literature which are likely to be of interest to everyone. Remarkably, some of these were brought about by young investigators from our team. My special thanks to them: you are more

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Peroxide signaling through thiol switches: chemical and biological aspects.

by Luis E. S. Netto

It is now well accepted that oxidants and other redox intermediates are not only damaging compounds, but also act as signaling molecules. This is especially evident for hydrogen peroxide, whose generation and degradation are finely regulated through multiple enzymatic systems. Proteins whose activities are based on Cysteine (Cys) residues are frequently reported to be oxidized in various biological systems in conditions where hydrogen peroxide is also generated. As the most parsimonious hypothesis, these proteins are frequently assumed to be directly oxidized by hydrogen peroxide, although this is not always supported by chemical data.

For instance, Protein Tyrosine Phosphatases

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Superoxide and nitric oxide induced nitrosative processes may follow unusual and different dynamic behaviors

by José Carlos Toledo

Possibly, most pathophysiological processes involving the radicals nitric oxide (NO•) and superoxide (O₂•–) depend on their simultaneous production and their favorable co-reaction to produce peroxynitrite. Peroxynitrite is an oxidant itself but in the presence of carbon dioxide it gives origin to radical species such as carbonate anion (CO₃•–) and nitrogen dioxide (NO₂•) radicals, both capable of stimulating oxidative and nitrosative events that damage biomolecules. The interplay of NO• and O₂•– in biological environments is complex, though. Using a fluorescent probe molecule to

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Visible, not only UV, light may also damage your hair and skin

by Mauricio Baptista

On the recent years, we aimed to understand the effects of visible light on skin and hair. We showed that melanin is able to photosensitize the generation of singlet oxygen both in the UVA (355nm) and in the visible (532nm) with similar yields and that the photosensitization of melanin forming singlet oxygen is the main cause of damage in hairs under exposition to visible light [1]. These results also suggest the possible role of visible light in damaging human skin, similarly to the well accepted effect of UVA light. In order to understand the effects

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More Tequila, please…: Organic nitrogen acquisition in Agave tequilana from endophytic bacteria by oxidative nitrogen scavenging mechanism

Redoxoma Highlights:
 • Superoxide and nitric oxide induced nitrosative processes may follow unusual and different dynamic behaviors
 • Visible, not only UV, light may also damage your hair and skin
 • More Tequila, please…: Organic nitrogen acquisition in Agave tequilana from endophytic bacteria by oxidative nitrogen scavenging mechanism
 • A novel oxidative pathway for human SOD1 aggregation is revealed and may contribute to ALS pathology
 • A novel ubiquitin-related marker in oxidative stress response

by Paolo Di Mascio

Historically, it was thought that plants derived all nitrogen (N) nutrition from the inorganic forms of N, NO3– and NH4+. However, it is now known that the principal form of N entering soils that do not receive inorganic fertilizer is organic N derived from microbial breakdown of organic matter, including amino acids, di and tri-peptides, DNA and proteins. Plants form symbiotic associations with endophytic bacteria

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A novel oxidative pathway for human SOD1 aggregation is revealed and may contribute to ALS pathology

by Ohara Augusto

ALS (amyotrophic lateral sclerosis) is a fatal disease characterized by the degeneration of motor neurons, resulting in progressive muscle weakness, atrophy, paralysis and death. Most cases of ALS are sporadic but about 10% of the cases have a genetic basis.ALS-causing mutations have been identified in several genes, but the mutation of Cu,Zn superoxide dismutase gene (SOD1) is the most studied and responsible for about 20% of the familial cases. SOD1-linked ALS patients exhibit pathology and symptoms similar to those of sporadic ALS patients, leading to the hypothesis that both forms of the disease have a common pathogenic mechanism. This hypothesis led to many advances in

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A novel ubiquitin-related marker in oxidative stress response

by Marilene Demasi

Protein polyubiquitination was first described as a post-translational modification to direct proteins for degradation. The ubiquitin molecule is covalently bound to the target protein and the polyubiquitin chain is created by successive attachments of ubiquitin through its carboxy-terminal Glycine mainly to Lysine48 (K48) residues of previously conjugated ubiquitin. Proteins tagged with a K48-linked polyubiquitin chain are directed for degradation. However, distinct ubiquitin chains are built up through other Lysine residues from ubiquitin, resulting in distinct structural patterns of ubiquitin complexes, which in most cases are unrelated to target protein degradation.

The

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Education page

Education page:
by Carmen Fernandez

by Carmen Fernandez

The CEPID-Redoxoma group had significant participation during events promoted by Universidade de São Paulo (USP) at the end of 2014 – I Virada Científica; Semana Nacional de Ciência e Tecnologia e 31ª Semana da Química. A folder about the project CEPID-Redoxoma was distributed to students and public in general during these events (Figure 1).

I Virada Científica was created by USP with the goal of making the world of science and technology closer to the São Paulo society. The event lasted 24 hours, starting 8am on October 11, and included workshops, experiments, shows, games, lectures, films and planetarium sessions – much of it aimed at children. Admission

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A radical-free talk about the scientific career: 3 Ds that allow for an E

by Francisco Laurindo

Can professionalism be learned? Certainly, to some extent, but likely not in the way you learn Chemistry or Biology, for example. But you can – and you should – discuss it, in order to trigger further thoughts that can help to achieve personal improvement. This is the idea of this short essay, derived from lectures given at our annual retreats over the years. While written with the young student in mind, I think it fits other ages as well… It should not be read rationally, but emotionally, just like it was written.

A general feeling among scientists is that science is not for everyone and that the scientific career is unusual in many aspects. To a good extent

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