OOL Home

Abstract (2001)

  1. Critical Aspects
  2. Energy Supplies
  3. Flow reactor
  4. Flatbed reactor
  5. Electrochem reactor
  6. The code
  7. Organic membrane
  8. Coda

References

Figures 1-25

The Origin of Life at a submarine alkaline seepage
 Michael J. Russell, Allan J. Hall, Laiq Rahman & Dugald Turner

VII. First organic membrane

An organic take-over of the iron sulfide/hydroxide mebranes must have taken place at an early stage of evolution but the nature of the first organic membrane is particularly puzzling. Although lipids, as self-assembling membrane fillers, might have been supplied from the hydrothermal system (McCollom et al. 1999, and see Freund et al. 2001), they are produced in low yield, and anyway, do not figure in Wächtershäuser's (1998) "canonical" gene cluster which bears no trace of lipid chemistry. Wächtershäuser tentatively suggests that the presence of proteins belonging to the secretory pathway in a gene cluster, conserved across 13 eubacteria and 6 archaebacteria, might indicate their role in building proteinaceous cell envelopes for organisms preceding the last universal common ancestor (LUCA). Genetically controlled proteinaceous cell envelopes would have the advantage of including metal clusters, such as the [Fe4S4] centres, within their structure. Indeed a polyferredoxin in the Methanothermus farvidus (Steigerwald et al. 1990) allows two electron transfer from inside to the outside of its membrane (Fig. 19).

Click images to view figures and captions.

Use 'Back' button on your browser to return here after viewing

Fig 19Figure 19. [Fe4S4] centres as ferredoxin-like domains in a hyperthermophilic methanogen Archaeon, Methanothermus farvidus, which allows two electron transfer across a membrane (Steigerwald et al. 1990).

 

 

VIII. Coda Next >>

VI. The Code << Prev.

Page last updated

23 October 2001