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.

Molecular Evolution of Biomembranes: Structural Equivalents and Phylogenetic Precursors of Sterols

Michel Rohmer, Pierrette Bouvier and Guy Ourisson
Proceedings of the National Academy of Sciences of the United States of America
Vol. 76, No. 2 (Feb., 1979), pp. 847-851
Stable URL: http://www.jstor.org/stable/69167
Page Count: 5
  • Read Online (Free)
  • Subscribe ($19.50)
  • 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.
Molecular Evolution of Biomembranes: Structural Equivalents and Phylogenetic Precursors of Sterols
Preview not available

Abstract

Derivatives of one triterpene family, the hopane family, are widely distributed in prokaryotes; they may be localized in membranes, playing there the same role as sterols play in eukaryotes, as a result of their similar size, rigidity, and amphiphilic character. Their biosynthesis embodies many primitive features compared to that of sterols and could have evolved toward the latter once aerobic conditions had been established. Membrane reinforcement appears to be achieved in other prokaryotes by other mechanisms, involving either ≈ 44- angstrom -long rigid hydrocarbon chains terminated by one polar group acting like a peg through the double-layer or similar chains terminated by two polar groups acting like tie-bars across the membrane. These inserts can be tetraterpenes (e.g., carotenoids). The biophysical function of membrane optimizers appears to have evolved toward sterols by changes limited to only a few enzymatic steps of the same fundamental biosynthetic processes.

Page Thumbnails

  • Thumbnail: Page 
847
    847
  • Thumbnail: Page 
848
    848
  • Thumbnail: Page 
849
    849
  • Thumbnail: Page 
850
    850
  • Thumbnail: Page 
851
    851