Mitochondrial F0F1 ATP synthase. Subunit regions on the F1 motor shielded by F0, functional significance, and evidence for an involvement of the unique F0 subunit F6

Y. H. Ko, J. Hullihen, S. Hong, P. L. Pedersen

Research output: Contribution to journalArticle

Abstract

Studies reported here were undertaken to gain greater molecular insight into the complex structure of mitochondrial ATP synthase (F0F1) and its relationship to the enzyme's function and motor-related properties. Significantly, these studies, which employed N-terminal sequence, mass spectral, proteolytic, immunological, and functional analyses, led to the following novel findings. First, at the top of F1 within F0F1, all six N-terminal regions derived from α + β subunits are shielded, indicating that one or more F0 subunits forms a 'cap.' Second, at the bottom of F1 within F0F1, the N-terminal region of the single δ subunit and the C-terminal regions of all three α subunits are shielded also by F0. Third, and in contrast, part of the γ subunit located at the bottom of F1 is already shielded in F1, indicating that there is a preferential propensity for interaction with other F1 subunits, most likely δ and ε. Fourth, and consistent with the first two conclusions above that specific regions at the top and bottom of F1 are shielded by F0, further proteolytic shaving of α and β subunits at these locations eliminates the capacity of F1 to couple a proton gradient to ATP synthesis. Finally, evidence was obtained that the F0 subunit called 'F6,' unique to animal ATP synthases, is involved in shielding F1. The significance of the studies reported here, in relation to current views about ATP synthase structure and function in animal mitochondria, is discussed.

Original languageEnglish (US)
Pages (from-to)32931-32939
Number of pages9
JournalJournal of Biological Chemistry
Volume275
Issue number42
DOIs
StatePublished - Oct 20 2000

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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