1a91
SUBUNIT C OF THE F1FO ATP SYNTHASE OF ESCHERICHIA COLI; NMR, 10 STRUCTURES
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| Gene: | UNCE (Escherichia coli) | ||||||
| Activity: | H(+)-transporting two-sector ATPase, with EC number 3.6.3.14 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
OverviewOverview
Subunit c is the H+-translocating component of the F1F0 ATP synthase complex. H+ transport is coupled to conformational changes that ultimately lead to ATP synthesis by the enzyme. The properties of the monomeric subunit in a single-phase solution of chloroform-methanol-water (4:4:1) have been shown to mimic those of the protein in the native complex. Triple resonance NMR experiments were used to determine the complete structure of monomeric subunit c in this solvent mixture. The structure of the protein was defined by >2000 interproton distances, 64 (3)JN alpha, and 43 hydrogen-bonding NMR-derived restraints. The root mean squared deviation for the backbone atoms of the two transmembrane helices was 0.63 A. The protein folds as a hairpin of two antiparallel helical segments, connected by a short structured loop. The conserved Arg41-Gln42-Pro43 form the top of this loop. The essential H+-transporting Asp61 residue is located at a slight break in the middle of the C-terminal helix, just prior to Pro64. The C-terminal helix changes direction by 30 +/- 5 degrees at the conserved Pro64. In its protonated form, the Asp61 lies in a cavity created by the absence of side chains at Gly23 and Gly27 in the N-terminal helix. The shape and charge distribution of the molecular surface of the monomeric protein suggest a packing arrangement for the oligomeric protein in the F0 complex, with the front face of one monomer packing favorably against the back face of a second monomer. The packing suggests that the proton (cation) binding site lies between packed pairs of adjacent subunit c.
About this StructureAbout this Structure
1A91 is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
ReferenceReference
Solution structure of the transmembrane H+-transporting subunit c of the F1F0 ATP synthase., Girvin ME, Rastogi VK, Abildgaard F, Markley JL, Fillingame RH, Biochemistry. 1998 Jun 23;37(25):8817-24. PMID:9636021
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