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

Abstract

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.

Qualitative Shotgun Proteomics Strategy for Protein Expression Profiling of Fish Otoliths

“…Proteins identified in the otoliths that are linked to mitochondrial processes included ADP/ATP translocase, which belongs to the mitochondrial carrier family [49]. We also found the ATP-binding cassette sub-family B (MDR/TAP), which regulates apoptotic and non-apoptotic cell death [50]; the ATP synthase-coupling factor 6, which was reported to be essential for energy transduction [51]; and the ATP synthase subunits alpha and beta that generate electron transport complexes for the respiratory chain [52]. Finally, we identified the voltage-dependent anion-selective channel 2 (VDAC2) protein, which is known to contribute to oxidative metabolism by facilitating solute transport across the outer mitochondrial membrane (OMM).…”

A computational study on mitogenome-encoded proteins of Pavo cristatus and Pavo muticus identifies key genetic variations with functional implications

“…Several studies have revealed the biochemical consequences of amino acid replacement of mtATP6 and indicated that they may alter mitochondrial ATP production, ranging from 30 to > 90% [ 51 – 54 ]. In another study, the mtATP6 of Champsocephalus gunnari (ice fish) was compared with the same protein from a few vertebrate species, and their data revealed that the variations observed between them could affect the structure and function of the protein leading to the unique physiology of the ice fish [ 55 ]. A similar effect might occur due to the variations observed at 6 positions in mtATP6 of P. muticus .…”

Quantitative Proteomics and Network Analysis of Differentially Expressed Proteins in Proteomes of Icefish Muscle Mitochondria Compared with Closely Related Red-Blooded Species

“…Icefish have been previously reported to show an increased coupling of proton transport and ATP synthase compared with red-blooded notothenioids [ 51 ] and this could be correlated to the increase in the specific subunits of complex V that are directly involved in proton translocation. Previously, we have shown the ATP synthase subunit 6 of complex V to be sequentially and structurally different in the icefish C. gunnari when compared to its red-blooded related species [ 52 ].…”