Chemical Evolution of AMINO
ACIDS and Peptides
The first steps towards the
origin of life
Bernd M. Rode
Theoretical Chemistry Division
Institute of General, Inorganic and Theoretical Chemistry,
University of Innsbruck, Austria
University of Vienna, 17-11-2010
The starting point of life – RNA/DNA or
Amino Acid, Peptide and Protein World?
Indications:
chemical stability
information theory
2 billion years only monocellular organisms
The Scenario: Earth 3.8 Ga ago – after formation of hydrosphere
How to investigate the origin of life ?
Oparin: The Primordial Soup
Miller-Urey Experiment
1953:
Simulation of
Atmospheric Processes
Water and Life
Chemical Evolution in an Aqueous Environment
Conditio sine qua non ?
Formation of C-H-O-N
compounds
in atmospheric/surface
processes
Atmosphere: carbon dioxide, nitrogen, water vapour
Atmosphere: carbon dioxide, nitrogen, water vapour
TITAN
SIMULATION
EXPERIMENT
Identification
of Compounds
Formed By
Lightning
Events
SIPF
Salt-Induced
Peptide Formation
Reaction
'ingredients':
NaCl, Cu(II), Amino Acids
SIPF
Salt-Induced
Peptide Formation
Reaction
Properties of the reaction
works with all amino acids
catalysed by gly, digly and his
slow racemisation
prefers α – over β-, γ- amino acids
takes place under varying conditions
compatible with presence of minerals
Availability of 'ingredients'
NaCl: primordial sea similar to today's
concentration
Cu(II): large deposits of copper minerals
in precambrian rocks
Amino acids: atmospheric processes
The connection
of the origin of
proteins with
today's living
organisms
CD spectra of SIPF complexes of L-Ala and D-Ala
Small differences are observed in pH dependence
and in complex stability constants
Tetrahedral distortion of the complex makes Cu(II) a chiral center
SUMMARY
Amino acids easily available from
atmospheric processes
Peptides are easily formed by the
SIPF reaction, also in presence of
clay minerals
The SIPF reaction determines the
preferential sequences of the peptides
The SIPF reaction delivers a possible
explanation for the preference of
L - amino acids in nature
All reactions are compatible with the
geochemical scenario assumed for
the primordial earth
.........and the other biomolecules ?
Sugars:
abiotic formation from formaldehyde?
Nucleic bases: abiotic formation from HCN, nitriles, amines, amides
and carbonic acids/aldehydes?
Fatty acids: abiotic formation from Miller-Urey-type experiments
RNA/DNA: probably much later, probably in protected environment
THANKS
to the co-workers
Michael Schwendinger
Artur Eder
Yongyos Yongyai
Yuttana Suwannachot
Juraj Bujdak
Kristof Plankensteiner
Hannes Reiner
Daniel Fitz
Thomas Jakschitz
Feng Li
to the funding
organisations
bm:wf
Austrian Federal Ministry
for Science and Research
Austrian Science Foundation