bims-resufa 2021-05-09 papers

Issue of 2021–05–09
two papers selected by
Vera Strogolova, Strong Microbials, Inc

Biochim Biophys Acta Bioenerg. 2021 Apr 28. pii: S0005-2728(21)00066-9. [Epub ahead of print] 148433

Identification of a cytochrome bc1 - aa3 supercomplex in Rhodobacter sphaeroides.

Olga Fedotovskaya, Ingrid Albertsson, Gustav Nordlund, Sangjin Hong, Robert B Gennis, Peter Brzezinski, Pia Ädelroth.

Respiration is carried out by a series of membrane-bound complexes in the inner mitochondrial membrane or in the cytoplasmic membrane of bacteria. Increasing evidence shows that these complexes organize into larger supercomplexes. In this work, we identified a supercomplex composed of cytochrome (cyt.) bc1 and aa3-type cyt. c oxidase in Rhodobacter sphaeroides. We purified the supercomplex using a His-tag on either of these complexes. The results from activity assays, native and denaturing PAGE, size exclusion chromatography, electron microscopy, optical absorption spectroscopy and kinetic studies on the purified samples support the formation and coupled quinol oxidation:O2 reduction activity of the cyt. bc1-aa3 supercomplex. The potential role of the membrane-anchored cyt. cy as a component in supercomplexes was also investigated.

Keywords: Bioenergetics; Cytochrome bc(1) complex; Electron transfer; R. sphaeroides; Respiratory supercomplex; aa(3)-type cytochrome c oxidase

DOI: https://doi.org/10.1016/j.bbabio.2021.148433

Integr Comp Biol. 2021 May 04. pii: icab057. [Epub ahead of print]

Bivalve molluscs as model systems for studying mitochondrial biology.

Fabrizio Ghiselli, Mariangela Iannello, Giovanni Piccinini, Liliana Milani.

The class Bivalvia is a highly successful and ancient taxon including ∼25,000 living species. During their long evolutionary history bivalves adapted to a wide range of physicochemical conditions, habitats, biological interactions, and feeding habits. Bivalves can have strikingly different size, and despite their apparently simple body plan, they evolved very different shell shapes, and complex anatomic structures. One of the most striking features of this class of animals is their peculiar mitochondrial biology: some bivalves have facultatively anaerobic mitochondria that allow them to survive prolonged periods of anoxia/hypoxia. Moreover, more than 100 species have now been reported showing the only known evolutionarily stable exception to the strictly maternal inheritance of mitochondria in animals, named doubly uniparental inheritance. Mitochondrial activity is fundamental to eukaryotic life, and thanks to their diversity and uncommon features, bivalves represent a great model system to expand our knowledge about mitochondrial biology, so far limited to a few species. We highlight recent works studying mitochondrial biology in bivalves at either genomic or physiological level. A link between these two approaches is still missing, and we believe that an integrated approach and collaborative relationships are the only possible ways to be successful in such endeavour.

Keywords: Doubly Uniparental Inheritance; heteroplasmy; mitochondrial bottleneck; mitochondrial genomics; mitochondrial inheritance; physiological adaptation

DOI: https://doi.org/10.1093/icb/icab057