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EMBO reports 3, 10, 982–987 (2002)
doi:10.1093/embo-reports/kvf196
Published online: October 2002
Composition of the central stalk of the Na+-pumping V-ATPase from Caloramator fervidus
Yuriy Chaban1, Trees Ubbink-Kok2, Wilko Keegstra1, Juke S. Lolkema2 & Egbert J. Boekema1
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1 Department of Biophysical Chemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherland
2 Department of Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
To whom correspondence should be addressed
Egbert J. Boekema Tel: +31 50 363 4225; Fax: +31 50 363 4800; boekema@chem.rug.nl
Received 22 April 2002; Accepted 13 August 2002.
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Abstract
The Na+-pumping V-ATPase complex of the thermophilic bacterium Caloramator fervidus was purified and dissociated under controlled conditions. The structure of purified V1-ATPase subcomplexes differing in subunit composition was analyzed by electron microscopy and single particle analysis of 50 000 projections. Difference mapping of subcomplex projections revealed the presence and position of two subunits in the central stalk. A density with an elongated shape similar to the  subunit of F-ATPases is partly located within V1 and corresponds, most likely, to subunit E. Subunit E is connected to the membrane-bound part V0 via subunit C, a spherical density that is connected to the center of V0. The presence of subunit C makes the central stalk substantially longer in comparison to the F-ATPases, in which the subunit connects directly to F0.
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