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Supplemental Material for Dunn, Akpinar, and Sharma, 2020

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posted on 04.06.2020 by Cory Dunn, Bala Anı Akpınar, Vivek Sharma

Hummingbirds in flight exhibit the highest mass-specific metabolic rate of all vertebrates. The bioenergetic requirements associated with sustained hovering flight raise the possibility of unique amino acid substitutions that would enhance aerobic metabolism. Here, we have identified a non-conservative substitution within the mitochondria-encoded cytochrome c oxidase subunit I (COI) that is fixed within hummingbirds, but not among other vertebrates. This unusual change is also rare among metazoans, but can be identified in several clades with diverse life histories. We performed atomistic molecular dynamics simulations using bovine and hummingbird COI models, thereby bypassing experimental limitations imposed by the inability to modify mtDNA in a site-specific manner. Intriguingly, our findings suggest that COI amino acid position 153 (bovine numbering system) provides control over the hydration and activity of a key proton channel in COX. We discuss potential phenotypic outcomes linked to this alteration encoded by hummingbird mitochondrial genomes.

History

Article title

An Unusual Amino Acid Substitution Within Hummingbird Cytochrome c Oxidase Alters a Key Proton-Conducting Channel

Manuscript #

G3/2020/401312

Article DOI

10.1534/g3.120.401312

Licence

Exports