Editorial

It is exciting to realize that the Newsletter is establishing itself as a communication vehicle between the Redoxoma group and a now expanded array of colleagues from Brazil and abroad. Welcome to all of you.

Thanks to the work of many colleagues, we have very exciting contributions, which emanate from research supported by our CEPID-Fapesp. In this issue, we can walk through intriguing paths, starting really from the beginning – with redox threads to the origin of life! And we end in a bold way, with a short essay from an experienced academic clinician, on how he interprets our redox area – leading us to think over where we should at the end direct our efforts. In

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Redox Reactions and the Origin of Life

The Radical-Free Corner | Redox Reactions and the Origin Life  Alicia Kowaltowski

by Alicia Kowaltowski

Peter Mitchell was awarded the 1978 Nobel Prize in Chemistry for his discovery of the chemiosmotic mechanism of ATP synthesis, a hypothesis he first published in 1961 [1]. Surprisingly, shortly before this seminal publication, Dr. Mitchell attended and wrote a paper for a symposium on the origins of life [2]. His scientific interests were obviously quite vast!

He was also a visionary: In his publication on the origins of life, Dr. Mitchell describes the importance of membranes, osmosis and the exchange of substances with the environment in the origins of life. He was spot on. Today, most early life evolution specialists agree that life

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Mitochondria can dictate your fate, especially if you’re a stem cell

Redoxoma Highlights | Mitochondria can dictate your fate, especially if you’re a stem cell  Maria F. Forni

by Maria F. Forni*

Known for over a century, mitochondria have become, during the last four decades, an important subject of research within several disciplines. This is mostly due to the fact that this organelle comprises the site of oxidative phosphorylation, the citric acid cycle, fatty acid oxidation, the urea cycle and the biosynthesis of iron-sulphur centres and haem. Moreover, mitochondria are an important redox-signaling node. Indeed, the bioenergetic status of a cell is dependent on the overall quality and relative abundance of the mitochondrial population it harbors. Recent evidence suggests that the control of mitochondrial mass and morphology occurs through the processes of fusion

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The hard path towards accurately measuring in vivo enzyme activity: the case of protein disulfide isomerase

by Denise C. Fernandes

Correct protein folding is a vital and extremely regulated cellular function. Disulfide bonds are essential determinants of the correctly folded protein structure. During the folding of nascent proteins into the endoplasmic reticulum (ER) lumen, essential enzymes promote disulfide bond insertion (oxidation) and their eventual repositioning (isomerization) when they are initially formed between wrong cysteines. These reactions are catalyzed by PDIs (protein disulfide isomerases), a family of enzymes that contains more than 20 members, from yeast to humans [1]. Thus, PDIs do not have one specific substrate, but rather a large variety of un/misfolded protein substrates.

Using

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Mitochondria-to-nucleus communication controls mitochondrial activity and stress resistance in yeast

Redoxoma Highlights | Mitochondria-to-nucleus communication controls mitochondrial activity and stress resistance in yeast by Fernanda M. Cunha

by Fernanda M. Cunha

Mitochondria are believed to be former free living bacteria that established a successful symbiotic relationship with eukaryotic cells in such a way that today, besides being crucial for the biosynthesis of intermediary metabolites, calcium homeostasis, coordination of apoptosis and ATP synthesis, most mitochondrial proteins are encoded by nuclear rather than mitochondrial DNA. In that scenario, communication pathways that relay signals from the nucleus to mitochondria as well as from mitochondria to the nucleus (the retrograde way) are mandatory to secure energetic and metabolic homeostasis. In yeast, the best characterized retrograde signaling pathway, activated whenever

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Yes, together we can…. A highly conserved histidine residue in 2-Cys peroxiredoxins acts as a pH sensor for oligomerization

by Luis E. S. Netto

Peroxiredoxin (Prx) enzymes are becoming more and more popular among other reasons due to their high reactivity towards hydroperoxides and to their abundance. As a consequence, Prxs are proposed as biological sensors of hydrogen peroxide. It is interesting to observe that since their beginnings (in the end of the 60’s), one feature that called attention was their ability to form high molecular weight species, visible by electron microscopy [1]. It was almost twenty years later that the thiol-dependent peroxidase activity of Prx enzymes was described.

Among Prx family of proteins, 2-Cys Prx enzymes (those belonging to the AhpC/Prx1 group) can adopt a wide array of quartenary

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Is cholesterol bad for mitochondria?

Cholesterol

by Sayuri Miyamoto

Cholesterol is an important component of cell membranes and plays essential structural and signaling roles. It is synthesized in the endoplasmic reticulum and distributed to other cell membranes/compartments through a tightly regulated trafficking system involving vesicular and non-vesicular processes [1]. Cholesterol distribution among intra-cellular membranes is not homogeneous. Mitochondria are cholesterol-poor organelles (less than 5 %). However, mitochondrial cholesterol is increased in cancer cell lines and treatment of these cells with statins (cholesterol lowering drugs) increases their susceptibility to chemotherapy [2].

How mitochondrial cholesterol could influence

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INTERVIEW Etelvino José Henriques Bechara: On fireflies and mental illnesses

Pesquisa FAPESP

http://revistapesquisa.fapesp.br/en/2015/03/23/etelvino-jose-henriques-bechara-on-fireflies-and-mental-illnesses

INTERVIEW
Etelvino José Henriques Bechara: On fireflies and mental illnesses

Chemist explains how highly reactive compounds known as free radicals act in cells, psychiatric disorders and glowing termite mounds

CARLOS FIORAVANTI | ED. 229 | MARCH 2015

While awaiting the response to his request for reinstatement to the University of São Paulo Chemistry Institute (IQ-USP), Etelvino Bechara said he had been without a laboratory, money with which to pursue research and students with whom to divvy up the work.  Despite all that, he never stopped exploring the paths that opened before him – ever since leaving Caparaó, the small town in Minas Gerais State where he was born and learned to read and write with adults at night school under lantern light.  On a day in

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Free radicals: should clinicians pay attention to them?

by Protasio L. da Luz*

Within the Cepid-Redoxoma, we are deeply involved in redox research and we consider this very important, of course. However, it is interesting at times to see how some meaningful outsiders interpret the area. The Radical-Free Corner challenged a highly experienced academic clinician-scientist, who kindly accepted this task (he happens to have been the Editor’s doctorate supervisor – a minor conflict of interest, I confess)

(Editor’s comment)

Oxidative stress pervades several areas of Medicine: aging, cancer, atherosclerosis and other degenerative conditions, principally. Several studies claim that it is the cause of aging. But while there is evidence for

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A comprehensive approach to identify redox and non-redox targets of Trx-like proteins

by Lia S. Nakao

Like the old dictum that says “birds of a feather flock together”, understanding the specific partners of a given protein provides an important clue about its function. Thioredoxin 1 (Trx1) is a well-known redox protein that contains a CXXC motif (cysteines residues flanking two aminoacid residues), responsible for its disulfide reductase function. The first (C-terminal) Cys of the motif attacks the disulfide of the target protein, producing a short lived mixed disulfide, which is reduced by the second (N-terminal resolving) Cys, releasing Trx1 and the target, in the oxidized and reduced forms, respectively. If the resolving Cys is replaced by a non-redox residue, such as

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