Basic Questions about the Origin of Life O N THE G ENETIC C ODE
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A ‘MOLECULAR DEAL’ between lipophilic peptides and hydrophilic nucleic acids helped to overcome the major selection obstacle of each class of compounds : Too low mobility and irreversible precipitation of peptides. Too high mobility and infinite dilution of nucleic acids. Basic Questions about the Origin of Life ON THE GENETIC CODE A proposition by Peter Strazewski, Lyon
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Basic Questions about the Origin of Life O N THE G ENETIC C ODE. HOW DID TRANSLATION OCCUR ?. A ‘M OLECULAR D EAL ’ between lipophilic peptides and hydrophilic nucleic acids helped to overcome the major selection obstacle of each class of compounds : - PowerPoint PPT Presentation
Transcript of Basic Questions about the Origin of Life O N THE G ENETIC C ODE
A ‘MOLECULAR DEAL’ between lipophilic peptides and hydrophilic nucleic acids helped to overcome the major
selection obstacle of each class of compounds : Too low mobility and irreversible precipitation of peptides.
Too high mobility and infinite dilution of nucleic acids.
Basic Questions about the Origin of Life
ON THE GENETIC CODE
A proposition by Peter Strazewski, Lyon
Angewandte Chemie International Edition in English,
1972, 11, 798-8301972
Angewandte Chemie International Edition in English,
1981, 20, 500-520
Angewandte Chemie International Edition in English,
1981, 20, 500-520
Journal of Molecular Evolution,
1989, 29, 465-474
A) 3'-aminoacyl-RNA
B) Uncoded peptidyl transfer
C) mRNA-encoded peptidyl transfer (PT)
D) ribosome-catalysed and mRNA-encoded PT
Eörs Szathmáry in:«Evolution: from
Cosmogenesis to Biogenesis»(B. Lukacs et al. eds.)
KFKI 1990, 50/C, 77-83
Origin of genetically encoded protein synthesis : A model based on selection for RNA peptidation
Origin of Life andEvolution of the Biosphere,
1991, 21, 165-176
A) 3'-aminoacyl-AMP + 3'-peptidyl-RNA
B) Uncoded peptidyl transfer
C) mRNA-encoded peptidyl transfer
Jeffrey Tze-Fei Wong
Early Middle Late
A1-AMP A3-tRNA3 A3-tRNA3
+ A2-A3-tRNA3 + A1-A2-tRNA2 + A1-A2-tRNA2
A1-A2-A3-tRNA3
===
===
TemplateRNA
III
On the origin of protein synthesis : A speculative model based on hairpin RNA structures
Journal of Theoretical Biology,
1994, 171, 303-8
A) Uncoded peptidyl transfer through (bulged) double-strand formation between
3'-aminoacyl-RNA hairpin (+) RNA hairpin (+) 5'-aminoacyl-RNA hairpin => 5'-dipeptidyl-RNA hairpin (-)
5'-aminoacyl-RNA hairpin (-) 5'-dipeptidyl-RNA hairpin (-)
B) Stabilisation of cruciforms between the above hairpins through mRNA
C) mRNA-encoded peptidyl transfer between 3'-aminoacyl and 3'-peptidyl-tRNAs
D) rRNA-catalysed peptidyl transfer
Massimo Di Giulio
1994
1994 (reproduced from 1987)
Experimentally taken care of by:
John D. Sutherland, Manchester, UKPrebiotic Aminoacylation of Nucleotides
Chemistry & Biodiversity 2004, 1, 203-246
More contributions to the origin of tRNA as a basis for the appearance of the genetic code and translation (and replication) :
Manfred Eigen, Peter Schuster, Ruthild Winkler 1972, 1981, 1989Jeffrey Tze-Fei Wong 1975-2006, ...Massimio Di Giulio 1989-2006, ...Toby Gibson & Angus Lamond 1990Tobias Dick & Wolfgang Schamel 1995Nancy Maizels & Alun Weiner 1987-1999
...Importance of compartmentalisation and the matrix effect :
William Hargreaves, Sean Mulvihill,David Deamer et al. 1977- ...
Pier Luigi Luisi, Peter Walde, Evelyne Blöchliger, Markus Blocher et al. 1998-2004
Jack Szostak, Martin Hanczyc 2001- ...
MAJOR PLAYERS
NUCLEICACIDS
replicateprimary
sequence
PROTEINS
recognise
LIPIDS
replicateshape
SUGARS
recognise
HYDROPHILES AMPHIPHILES
A-RNA hairpin-3'-oligopeptidehydrophilic lipophilic
shallowgroove
deepgroove
shallowgroove
-helixA-RNA
5’-RNA-3’-(Ala)21
UUCGloop
ACCAstack
ACCAstack
UUCGloop
deepgroove
-helix
helixdipole
shallowgroove
shallowgroove
deepgroove
A-RNA hairpin-3'-oligopeptidehydrophilic lipophilic
-strandA-RNA
5’-RNA-3’-(Ala)21UUCGloop
ACCAstack
MOLECULAR DEAL
N.A. to P.P.: « I'll help you to stay in solution, if you help me not to get washed away »
P.P. to N.A.: « I'll help you to stick around, if you help me to hold sufficient distance to my buddies »
love you both
