Sequence and structure comparison of ATP synthase F0 subunits 6 and 8 in notothenioid fish.

AbstractThe Channichthyidae family (icefish) are the only known vertebrate species to be devoid of haemoglobin. Mitochondrial changes such as tight coupling of the mitochondria have facilitated sustained oxygen and respiratory activity in the fish. This makes it important to appreciate features in the sequence and structure of the proteins directly involved in proton transport, which could have physiological implications. ATP synthase subunit a (ATP6) and subunit 8 (ATP8) are proteins that function as part of the F0 component (proton pump) of the F0F1complex. Both are encoded by the mitochondrial genome and involved in oxidative phosphorylation. To explore mitochondrial sequence variation for ATP6 and ATP8 we have gathered sequences and predicted structures of these two proteins of fish from the Notothenioidei sub-order, a sub-Antarctic species. We compared these with seven other vertebrate species in order to reveal whether there might be physiologically important differences that can help us to understand the unique biology of the icefish.

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Sequence and structure comparison of ATP synthase F0 subunits 6 and 8 in notothenioid fish

PLoS ONE ◽

10.1371/journal.pone.0245822 ◽

2021 ◽

Vol 16 (10) ◽

pp. e0245822

Author(s):

Gunjan Katyal ◽

Brad Ebanks ◽

Magnus Lucassen ◽

Chiara Papetti ◽

Lisa Chakrabarti

Keyword(s):

Amino Acid ◽

Atp Synthase ◽

Proton Transport ◽

Sequence Variation ◽

Respiratory Activity ◽

Tight Coupling ◽

Structure Comparison ◽

Subunit A ◽

Structural Impact ◽

Physiological Pathways

Mitochondrial changes such as tight coupling of the mitochondria have facilitated sustained oxygen and respiratory activity in haemoglobin-less icefish of the Channichthyidae family. We aimed to characterise features in the sequence and structure of the proteins directly involved in proton transport, which have potential physiological implications. ATP synthase subunit a (ATP6) and subunit 8 (ATP8) are proteins that function as part of the F0 component (proton pump) of the F0F1complex. Both proteins are encoded by the mitochondrial genome and involved in oxidative phosphorylation. To explore mitochondrial sequence variation for ATP6 and ATP8 we analysed sequences from C. gunnari and C. rastrospinosus and compared them with their closely related red-blooded species and eight other vertebrate species. Our comparison of the amino acid sequence of these proteins reveals important differences that could underlie aspects of the unique physiology of the icefish. In this study we find that changes in the sequence of subunit a of the icefish C. gunnari at position 35 where there is a hydrophobic alanine which is not seen in the other notothenioids we analysed. An amino acid change of this type is significant since it may have a structural impact. The biology of the haemoglobin-less icefish is necessarily unique and any insights about these animals will help to generate a better overall understanding of important physiological pathways.

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The Unique Biology of Mitochondrial Genome Instability in Plants

Annual Plant Reviews online ◽

10.1002/9781119312994.apr0323 ◽

2018 ◽

pp. 36-49

Author(s):

Sally A. Mackenzie

Keyword(s):

Mitochondrial Genome ◽

Genome Instability ◽

Unique Biology

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Biochemical and Genetic Analysis of the Mitochondrial Response of Yeast to BAX and BCL-XL

Molecular and Cellular Biology ◽

10.1128/mcb.20.9.3125-3136.2000 ◽

2000 ◽

Vol 20 (9) ◽

pp. 3125-3136 ◽

Cited By ~ 114

Author(s):

Atan Gross ◽

Kirsten Pilcher ◽

Elizabeth Blachly-Dyson ◽

Emy Basso ◽

Jennifer Jockel ◽

...

Keyword(s):

Cell Death ◽

Mitochondrial Genome ◽

Atp Synthase ◽

Mitochondrial Permeability Transition ◽

Family Members ◽

Growth Arrest ◽

Anion Channel ◽

Cell Killing ◽

Β Subunit ◽

Voltage Dependent Anion Channel

ABSTRACT The BCL-2 family includes both proapoptotic (e.g., BAX and BAK) and antiapoptotic (e.g., BCL-2 and BCL-XL) molecules. The cell death-regulating activity of BCL-2 members appears to depend on their ability to modulate mitochondrial function, which may include regulation of the mitochondrial permeability transition pore (PTP). We examined the function of BAX and BCL-XL using genetic and biochemical approaches in budding yeast because studies with yeast suggest that BCL-2 family members act upon highly conserved mitochondrial components. In this study we found that in wild-type yeast, BAX induced hyperpolarization of mitochondria, production of reactive oxygen species, growth arrest, and cell death; however, cytochrome c was not released detectably despite the induction of mitochondrial dysfunction. Coexpression of BCL-XL prevented all BAX-mediated responses. We also assessed the function of BCL-XL and BAX in the same strain of Saccharomyces cerevisiae with deletions of selected mitochondrial proteins that have been implicated in the function of BCL-2 family members. BAX-induced growth arrest was independent of the tested mitochondrial components, including voltage-dependent anion channel (VDAC), the catalytic β subunit or the δ subunit of the F0F1-ATP synthase, mitochondrial cyclophilin, cytochrome c, and proteins encoded by the mitochondrial genome as revealed by [rho 0] cells. In contrast, actual cell killing was dependent upon select mitochondrial components including the β subunit of ATP synthase and mitochondrial genome-encoded proteins but not VDAC. The BCL-XL protection from either BAX-induced growth arrest or cell killing proved to be independent of mitochondrial components. Thus, BAX induces two cellular processes in yeast which can each be abrogated by BCL-XL: cell arrest, which does not require aspects of mitochondrial biochemistry, and cell killing, which does.

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