title: Identification of critical residues of subunit H in its interaction with subunit E of the A-ATP synthase from Methanocaldococcus jannaschii.
abstract: The boomerang-like H subunit of A(1)A(0) ATP synthase forms one of the peripheral stalks connecting the A(1) and A(0) sections. Structural analyses of the N-terminal part (H1-47) of subunit H of the A(1)A(0) ATP synthase from Methanocaldococcus jannaschii have been performed by NMR spectroscopy. Our initial NMR structural calculations for H1-47 indicate that amino acid residues 7-44 fold into a single alpha-helical structure. Using the purified N- (E1-100) and C-terminal domains (E101-206) of subunit E, NMR titration experiments revealed that the N-terminal residues Met1-6, Lys10, Glu11, Ala15, Val20 and Glu24 of H1-47 interact specifically with the N-terminal domain E1-100 of subunit E. A more detailed picture regarding the residues of E1-100 involved in this association was obtained by titration studies using the N-terminal peptides E1-20, E21-40 and E41-60. These data indicate that the N-terminal tail E41-60 interacts with the N-terminal amino acids of H1-47, and this has been confirmed by fluorescence correlation spectroscopy results. Analysis of (1)H-(15)N heteronuclear single quantum coherence (HSQC) spectra of the central stalk subunit F in the presence and absence of E101-206 show no obvious interaction between the C-terminal domain of E and subunit F. The data presented provide, for the first time, structural insights into the interaction of subunits E and H, and their arrangement within A(1)A(0) ATP synthase.
authors.affiliation: School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore.
authors.forename: Shovanlal
authors.initials: S
authors.lastname: Gayen
authors.forename: Asha M
authors.initials: AM
authors.lastname: Balakrishna
authors.forename: Goran
authors.initials: G
authors.lastname: Biuković
authors.forename: Wu
authors.initials: W
authors.lastname: Yulei
authors.forename: Cornelia
authors.initials: C
authors.lastname: Hunke
authors.forename: Gerhard
authors.initials: G
authors.lastname: Grüber
mesh_terms: D025181:ATP Synthetase Complexes / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D000595:Amino Acid Sequence; D015870:Gene Expression; D017016:Methanococcaceae / Q000201:enzymology* / Q000235:genetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D011485:Protein Binding; D020836:Protein Structure, Quaternary; D021122:Protein Subunits / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D017186:Titrimetry
chemical_list: D021122:Protein Subunits; D025181:ATP Synthetase Complexes