Structural characterization of the interaction of the delta and alpha subunits of the Escherichia coli F1F0-ATP synthase by NMR spectroscopy.
A critical point of interaction between F(1) and F(0) in the bacterial F(1)F(0)-ATP synthase is formed by the alpha and delta subunits. Previous work has shown that the N-terminal domain (residues 3-105) of the delta subunit forms a 6 alpha-helix bundle [Wilkens, S., Dunn, S. D., Chandler, J., Dahlquist, F. W., and Capaldi, R. A. (1997) Nat. Struct. Biol. 4, 198-201] and that the majority of the binding energy between delta and F(1) is provided by the interaction between the N-terminal 22 residues of the alpha- and N-terminal domain of the delta subunit [Weber, J., Muharemagic, A., Wilke-Mounts, S., and Senior, A. E. (2003) J. Biol. Chem. 278, 13623-13626]. We have now analyzed a 1:1 complex of the delta-subunit N-terminal domain and a peptide comprising the N-terminal 22 residues of the alpha subunit by heteronuclear protein NMR spectroscopy. A comparison of the chemical-shift values of delta-subunit residues with and without alpha N-terminal peptide bound indicates that the binding interface on the N-terminal domain of the delta subunit is formed by alpha helices I and V. NOE cross-peak patterns in 2D (12)C/(12)C-filtered NOESY spectra of the (13)C-labeled delta-subunit N-terminal domain in complex with unlabeled peptide verify that residues 8-18 in the alpha-subunit N-terminal peptide are folded as an alpha helix when bound to delta N-terminal domain. On the basis of intermolecular contacts observed in (12)C/(13)C-filtered NOESY experiments, we describe structural details of the interaction of the delta-subunit N-terminal domain with the alpha-subunit N-terminal alpha helix.
Wilkens
Stephan
S
Departments of Biochemistry, University of California at Riverside, Riverside, California 92521, USA. stephan.wilkens@ucr.edu
Borchardt
Dan
D
Weber
Joachim
J
Senior
Alan E
AE
D000595:Amino Acid Sequence; D025243:Bacterial Proton-Translocating ATPases / Q000737:chemistry* / Q000235:genetics; D001665:Binding Sites; D004578:Electron Spin Resonance Spectroscopy; D004926:Escherichia coli / Q000201:enzymology; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000737:chemistry*
D021122:Protein Subunits; D025243:Bacterial Proton-Translocating ATPases