Low resolution structure of subunit b (b 22–156) of Escherichia coli F1FO ATP synthase in solution and the b−δ assembly

Abstract

The first low resolution solution structure of the soluble domain of subunit b (b (22-156)) of the Escherichia coli F(1)F(O) ATPsynthase was determined from small-angle X-ray scattering data. The dimeric protein has a boomerang-like shape with a total length of 16.2 +/- 0.3 nm. Fluorescence correlation spectroscopy (FCS) shows that the protein binds effectively to the subunit delta, confirming their described neighborhood. Using the recombinant C-terminal domain (delta(91-177)) of subunit delta and the C-terminal peptides of subunit b, b (120-140) and b (140-156), FCS titration experiments were performed to assign the segments involved in delta-b assembly. These data identify the very C-terminal tail b (140-156) to interact with delta(91-177). The novel 3D structure of this peptide has been determined by NMR spectroscopy. The molecule adopts a stable helix formation in solution with a flexible tail between amino acid 140 to 145.

Solution Structure, Determined by Nuclear Magnetic Resonance, of the b30-82 Domain of Subunit b of Escherichia coli F 1 F o ATP Synthase

“…The crystallographic structure of the major part of the dimerization domain, b62-122, revealed an ␣-helix with a length of 9.0 nm (12). Most recently, the NMR solution structure of the very C-terminal segment, b140-156, which interacts with the C terminus of subunit ␦ (␦91-177), has been determined by NMR spectroscopy (26). This molecule adopts a stable helix formation in solution with a flexible tail between amino acid residues 140 and 145.…”

“…This molecule adopts a stable helix formation in solution with a flexible tail between amino acid residues 140 and 145. SAXS (26) and analytical ultracentrifuge studies have indicated that the soluble domain of subunit b (b21-156, b22-156) is dimeric in solution (12). So far, no high-resolution structure of the tether domain, including residues 25 to 52, or the N-terminal segment of the dimerization domain, which is formed by residues 53 to 122, is available (14).…”

ATPG is required for the accumulation and function of chloroplast ATP synthase in Arabidopsis

“…It is mainly located in the unstacked regions of thylakoid membranes. The chloroplast ATP synthase consists of two parts, the hydrophilic CF 1 (subunit  3 ,  3 , ,  and ) and the membrane integrated CF o (subunits I, II, III 14 and IV). The CF 1 contains the nucleotide binding, catalytic and regulatory sites of ATP complex.…”

“…The CF o is involved in the proton transport through thylakoids [1]. These two parts are connected by a central stalk consisting of subunits , , III 14 and a peripheral stalk composed of subunits I, II and  [2]. The proton movement through subunit III complex drives the rotation of subunits  and  in catalytic core of  3  3 hexamer to catalyze ATP synthesis [3,4].…”

“…Different subunit compositions of the peripheral stalk in photosynthetic organisms appear to be a better adaptation to combine with different sites of CF 1 [12]. Although the construction and function of subunit b in E. coli have been studied in great detail [13,14], the knowledge about subunits II and I of chloroplast ATP synthase is limited. The nuclear atpG gene encoding the subunit II of chloroplast ATP synthase has been thought to be a duplication of atpF encoding the subunit I [15], but the secondary structures of two subunits are different significantly.…”