1a91
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SUBUNIT C OF THE F1FO ATP SYNTHASE OF ESCHERICHIA COLI; NMR, 10 STRUCTURES
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. Active as H(+)-transporting two-sector ATPase, with EC number 3.6.3.14 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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