Small-Angle X-ray Scattering Reveals the Solution Structure of the Peripheral Stalk Subunit H of the A1AO ATP Synthase from Methanocaldococcus jannaschii and Its Binding t
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- 作者：Goran Biukovi
//pubs.acs.org/images/entities/cacute.gif" border="0"> ; Manfred Rö ; ssle ; Shovanlal Gayen ; Yuguang Mu ; Gerhard Grü ; ber
- 刊名：Biochemistry
- 出版年：2007
- 出版时间：February 27, 2007
- 年：2007
- 卷：46
- 期：8
- 页码：2070 - 2078
- 全文大小：448K
- 年卷期：v.46,no.8(February 27, 2007)
- ISSN：1520-4995
文摘
The H subunit of the A1AO ATP synthase is a component of one of the peripheral stalksconnecting the A1 and AO domain. Subunit H of the Methanocaldococcus jannaschii A1AO ATP synthasewas analyzed by small-angle X-ray scattering (SAXS) in order to determine the first low-resolution structureof this molecule in solution. Independent to the concentration used, the protein is dimeric and has aboomerang-like shape, divided into two arms of 12.0 and 6.8 nm in length. Circular dichroism (CD)spectroscopy revealed that subunit H is comprised of 78% 
-helix and a coiled-coil arrangement. Tounderstand the orientation of the helices and the localization of the N- and C-termini inside the dimer,three truncated forms of subunit H (H8-104, H1-98, and H8-98) were expressed, purified, and analyzed byCD. SAXS experiments of H1-98 show that the maximum dimension of the truncated protein dropped to15.1 nm. Comparison of the low-resolution shapes of H and H1-98 indicates that this goes along withstructural changes in the C-terminal arm of the boomerang-like structure. Together with the result of adisulfide formation of a fourth truncated form, H1-47, with a cysteine at position 47, the data suggest aparallel -helical interaction. In addition, all four truncated proteins are dimeric in solution. Tryptophanemission spectra showed specific binding of H and H8-104 to the neighboring, catalytic A subunit, whichcould not be detected in the presence of H1-98. Finally, the arrangement of H within the A1AO ATPsynthase is presented.
-helix and a coiled-coil arrangement. Tounderstand the orientation of the helices and the localization of the N- and C-termini inside the dimer,three truncated forms of subunit H (H8-104, H1-98, and H8-98) were expressed, purified, and analyzed byCD. SAXS experiments of H1-98 show that the maximum dimension of the truncated protein dropped to15.1 nm. Comparison of the low-resolution shapes of H and H1-98 indicates that this goes along withstructural changes in the C-terminal arm of the boomerang-like structure. Together with the result of adisulfide formation of a fourth truncated form, H1-47, with a cysteine at position 47, the data suggest aparallel -helical interaction. In addition, all four truncated proteins are dimeric in solution. Tryptophanemission spectra showed specific binding of H and H8-104 to the neighboring, catalytic A subunit, whichcould not be detected in the presence of H1-98. Finally, the arrangement of H within the A1AO ATPsynthase is presented.