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Identification of critical residues of subunit H in its interaction with subunit E of the A‐ATP synthase from Methanocaldococcus jannaschii
Author(s) -
Gayen Shovanlal,
Balakrishna Asha M.,
Biuković Goran,
Yulei Wu,
Hunke Cornelia,
Grüber Gerhard
Publication year - 2008
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2008.06338.x
Subject(s) - protein subunit , atp synthase , atp synthase gamma subunit , heteronuclear single quantum coherence spectroscopy , tryptophan synthase , titration , heteronuclear molecule , stereochemistry , chemistry , crystallography , biochemistry , nuclear magnetic resonance spectroscopy , amino acid , biology , tryptophan , atpase , enzyme , gene , inorganic chemistry , atp hydrolysis
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 α‐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.