Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

If You Use a Screen Reader

This content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.

Structural Aspects of Proton-Pumping ATPases

J. E. Walker, I. M. Fearnley, R. Lutter, R. J. Todd and M. J. Runswick
Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
Vol. 326, No. 1236, Microbial Membrane Transport Systems (Jan. 30, 1990), pp. 367-378
Published by: Royal Society
Stable URL: http://www.jstor.org/stable/2398752
Page Count: 13
  • Read Online (Free)
  • Cite this Item
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Structural Aspects of Proton-Pumping ATPases
Preview not available

Abstract

ATP synthase is found in bacteria, chloroplasts and mitochondria. The simplest known example of such an enzyme is that in the eubacterium Escherichia coli; it is a membrane-bound assembly of eight different polypeptides assembled with a stoichiometry of α3β3γ1δ1ε1 a1 b2c10-12. The first five of these constitute a globular structure, F1-ATPase, which is bound to an instrinsic membrane domain, F0, an assembly of the three remaining subunits. ATP synthases driven by photosynthesis are slightly more complex. In chloroplasts, and probably in photosynthetic bacteria, they have nine subunits, all homologues of the components of the E. coli enzyme; the additional subunit is a duplicated and diverged relation of subunit b. The mammalian mitochondrial enzyme is more complex. It contains 14 different polypetides, of which 13 have been characterized. Two membrane components, a (or ATPase-6) and A6L, are encoded in the mitochondrial genome in overlapping genes and the remaining subunits are nuclear gene products that are translated on cytoplasmic ribosomes and then imported into the organelle. The sequences of the proteins of ATP-synthase have provided information about amino acids that are important for its function. For example, amino acids contributing to nucleotide binding sites have been identified. Also, they provide the basis of models of secondary structure of membrane components that constitute the transmembrane proton channel. An understanding of the coupling of the transmembrane potential gradient for protons, ΔμH+ , to ATP synthesis will probably require the determination of the structure of the entire membrane bound complex. Crystals have been obtained of the globular domain, F1-ATPase. They diffract to a resolution of 3-4 A\dagger and data collection is in progress. As a preliminary step towards crystallization of the entire complex, we have purified it from bovine mitochondria and reconstituted it into phospholipid vesicles.

Page Thumbnails

  • Thumbnail: Page 
367
    367
  • Thumbnail: Page 
368
    368
  • Thumbnail: Page 
369
    369
  • Thumbnail: Page 
370
    370
  • Thumbnail: Page 
371
    371
  • Thumbnail: Page 
372
    372
  • Thumbnail: Page 
373
    373
  • Thumbnail: Page 
374
    374
  • Thumbnail: Page 
[unnumbered]
    [unnumbered]
  • Thumbnail: Page 
375
    375
  • Thumbnail: Page 
376
    376
  • Thumbnail: Page 
377
    377
  • Thumbnail: Page 
378
    378