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PDBsum entry 3j9v
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312 a.a.
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392 a.a.
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210 a.a.
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115 a.a.
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593 a.a.
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457 a.a.
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345 a.a.
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105 a.a.
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217 a.a.
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461 a.a.
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(+ 4 more)
150 a.a.
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References listed in PDB file
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Key reference
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Title
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Electron cryomicroscopy observation of rotational states in a eukaryotic v-Atpase.
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Authors
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J.Zhao,
S.Benlekbir,
J.L.Rubinstein.
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Ref.
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Nature, 2015,
521,
241-245.
[DOI no: ]
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PubMed id
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Abstract
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Eukaryotic vacuolar H(+)-ATPases (V-ATPases) are rotary enzymes that use energy
from hydrolysis of ATP to ADP to pump protons across membranes and control the
pH of many intracellular compartments. ATP hydrolysis in the soluble catalytic
region of the enzyme is coupled to proton translocation through the
membrane-bound region by rotation of a central rotor subcomplex, with peripheral
stalks preventing the entire membrane-bound region from turning with the rotor.
The eukaryotic V-ATPase is the most complex rotary ATPase: it has three
peripheral stalks, a hetero-oligomeric proton-conducting proteolipid ring,
several subunits not found in other rotary ATPases, and is regulated by
reversible dissociation of its catalytic and proton-conducting regions. Studies
of ATP synthases, V-ATPases, and bacterial/archaeal V/A-ATPases have suggested
that flexibility is necessary for the catalytic mechanism of rotary ATPases, but
the structures of different rotational states have never been observed
experimentally. Here we use electron cryomicroscopy to obtain structures for
three rotational states of the V-ATPase from the yeast Saccharomyces cerevisiae.
The resulting series of structures shows ten proteolipid subunits in the c-ring,
setting the ATP:H(+) ratio for proton pumping by the V-ATPase at 3:10, and
reveals long and highly tilted transmembrane α-helices in the a-subunit that
interact with the c-ring. The three different maps reveal the conformational
changes that occur to couple rotation in the symmetry-mismatched soluble
catalytic region to the membrane-bound proton-translocating region. Almost all
of the subunits of the enzyme undergo conformational changes during the
transitions between these three rotational states. The structures of these
states provide direct evidence that deformation during rotation enables the
smooth transmission of power through rotary ATPases.
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