Mais design inteligente no menor motor 'vivo' até aqui conhecido

Structure of intact Thermus thermophilus V-ATPase by cryo-EM reveals organization of the membrane-bound VO motor

Wilson C. Y. Lau and John L. Rubinstein1
- Author Affiliations

Molecular Structure and Function Program, The Hospital for Sick Children Research Institute and Department of Biochemistry, University of Toronto, Toronto, Ontario M5G 1X8, Canada
Edited by David DeRosier, Brandeis University, Waltham, MA, and approved December 8, 2009 (received for review September 25, 2009)

Abstract

The eubacterium Thermus thermophilus uses a macromolecular assembly closely related to eukaryotic V-ATPase to produce its supply of ATP. This simplified V-ATPase offers several advantages over eukaryotic V-ATPases for structural analysis and investigation of the mechanism of the enzyme. Here we report the structure of the complex at ∼16 Å resolution as determined by single particle electron cryomicroscopy (cryo-EM). The resolution of the map and our use of cryo-EM, rather than negative stain EM, reveals detailed information about the internal organization of the assembly. We could separate the map into segments corresponding to subunits A and B, the threefold pseudosymmetric C-subunit, a central rotor consisting of subunits D and F, the L-ring, the stator subcomplex consisting of subunits I, E, and G, and a micelle of bound detergent. The architecture of the VO region shows a remarkably small area of contact between the I-subunit and the ring of L-subunits and is consistent with a two half-channel model for proton translocation. The arrangement of structural elements in VO gives insight into the mechanism of torque generation from proton translocation.

membrane protein single particle analysis

Footnotes

1To whom correspondence may be addressed at:

Molecular Structure and Function Program, The Hospital for Sick Children, 555 University Avenue, Rm. 3330, Toronto, Ontario M5G 1X8, Canada

Email: john.rubinstein@utoronto.ca

Author contributions: J.L.R. designed research; W.C.Y.L. performed research; J.L.R. contributed new reagents/analytic tools, W.C.Y.L. and J.L.R. analyzed data; and W.C.Y.L. and J.L.R. wrote the paper.

The authors declare no conflict of interest.

This article is a PNAS Direct Submission.

This article contains supporting information online at www.pnas.org/cgi/content/full/0911085107/DCSupplemental. [A must download/Download imperdível]

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