JTW's Evolutionary Origins - Author: Wachtershauser, Gunter

Wachtershauser's Theory - Postulates

Postulate #1

[pp. 121]

The geochemical setting of the origin of life is
a local anaerobic aqueous environment
with elevated temperature and pressure
in which the oxidative formation of pyrite
from hydrogen sulfide and ferrous ions (or FeS)
drives the first autocatalytic carbon fixation metabolism
and its evolution.

Postulate #2
Rxn a

Reductive Carboxlyation Reaction Type:

R-COSH + CO₂ + FeS --> R-CO-COOH + FeS₂

Postulate #3
Rxn c

Reductive Desulphuration Reaction Type:

-C-SH + FeS --> -C-H + FeS₂

General Reaction Class:

HS-C=X

where X may be
=O, =S, =N-, =C

HS-C-Y

where Y may be
-H, -S-, -O-, -N

Postulate #4

[pp. 139]

Inorganic Fe-S clusters,
akin to those in iron-sulphur enzymes,
are operative on the surface of the growing pyrite crystal.

Postulate #5

[pp. 139]

Disulphido ligands (H-S-S- or -S-S-) of Fe-S clusters
are structural elements or intermediates
in the mechanisms of iron-sulphur enzymes
(not ferrodoxins).

Postulate #6
Rxn h

[pp. 141]

In the presence of hydrogen sulfide
alpha-ketoacids
are converted into
2,3-dimercaptoacids.

CH₃-C0-COOH + 2H₂S --> HS-CH₂-CHSH-COOH + H₂O

dG` ~ -30 kJ/mol

Not yet demonstrated (as of 1993)
Experimental support for this reaction
by formation of 2,3-diethylthio-propionate from pyruvate
(Kawazoe and Taguchi, 1972)

Postulate #7
Rxn n

Reductive Amination:

-CO- + NH₃ + FeS + H₂S --> -CHNH₂- + FeS₂ + H₂0

• Wachtershauser, Gunter
  • Groundworks for an Evolutionary Biochemistry: The Iron-Sulphur World
  • Progress in Biophysics and Molecular Biology: Vol. 58, No. 2, pp.85-202
  • 1992
  • [Pubmed]

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