Abstract
AbstractThe passage of protons across membranes through F1Fo-ATP synthases spins their rotors and drives synthesis of ATP. While the principle of torque generation by proton transfer is known, the mechanisms and routes of proton access and release and their evolution are not fully understood. Here, we show that the entry site and path of protons in the lumenal half-channel of mitochondrial ATP synthases are largely defined by a short N-terminal α-helix of subunit-a. InTrypanosoma bruceiand other Euglenozoa, the α-helix is part of another polypeptide chain that is a product of subunit-a gene fragmentation. This α-helix and other elements forming the proton pathway are widely conserved across eukaryotes and in Alphaproteobacteria, the closest extant relatives of mitochondria, but not in other bacteria. The α-helix blocks one of two proton routes found inEscherichia coli, resulting in the single proton entry site in mitochondrial and alphaproteobacterial ATP synthases. Thus, the shape of the access half-channel predates eukaryotes and originated in the lineage from which mitochondria evolved by endosymbiosis.
Publisher
Cold Spring Harbor Laboratory
Reference56 articles.
1. The New Tree of Eukaryotes;Trends Ecol Evol,2020
2. Buzzard E , McLaren M , Bragoszewski P , Brancaccio A , Ford H , Daum B , Kuwabara P , Collinson I , Gold VAM, unpublished data, https://www.biorxiv.org/content/10.1101/2023.02.02.526626v2
3. Interaction between Glu-219 and His-245 within the a subunit of F1Fo-ATPase in Escherichia coli;Journal of Biological Chemistry,1988
4. Proton Translocation by the F1FOATPase of Escherichia coli;Journal of Biological Chemistry,1989
5. Structure of ATP synthase from ESKAPE pathogen Acinetobacter baumannii;Sci Adv,2022