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Chembiogenesis 2005 and Systems Chemistry Workshop.

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Meeting Reviews
Chembiogenesis 2005 and
Systems Chemistry Workshop**
Johanna Stankiewicz* and Lars Henning Eckardt
Despite the wealth of insight derived
from existing forms of life, biology by
itself has not been able so far to answer
the question concerning the origin of its
subject. Finding the roots of biology in
chemical systems calls for an integrated
endeavor in which chemistry interfaces
with molecular biology, theoretical biology, and complex systems research.
COST Chemistry Action D27 was
founded in early 2002, and its main
objective was seen in the development
of the chemistry connected with the
origin of life and early evolution of life
on earth, while giving special emphasis
on self-replicating systems, prebiotic
synthesis of nucleic acids and polypeptides, as well as simple protocells as
early models of biological cells.
Two meetings on these topics, organized
by G(nter von Kiedrowski
(Bochum, Germany) and his team,
were held at Venice International University located on the small island of
San Servolo in the Laguna of Venice.
The first of these meetings, “Chembiogenesis 2005”, was the midterm evaluation conference of the European
Chemistry Action COST D27 “Prebiotic Chemistry and Early Evolution”
and was attended by nearly 90 participants. The second, “Systems Chemistry”, was another occasion to unite the
[*] J. Stankiewicz, L. H. Eckardt
Bioorganic Chemistry
Ruhr-Universit#t Bochum
Universit#tsstrasse 150, NC2/173
44780 Bochum (Germany)
E-mail: johanna.stankiewicz@oc1.rub.de
[**] Chembiogenesis 2005, COST Action D27:
Prebiotic Chemistry and Early Evolution,
Midterm Evaluation Conference, Venice,
September 28–-October 1, 2005.
Systems Chemistry Workshop, Venice,
October 3–4, 2005.
342
main speakers of Chembiogenesis in a
workshop aiming to define a new field of
chemistry seen as the offspring of prebiotic and supramolecular chemistry on
the one hand and theoretical biology
and complex systems research on the
other.
During the course of Chembiogenesis 2005, members of six European
workgroups reported on their activities,
embedded into a framework of keynote
and invited lectures from internationally
leading scientists. The four-day conference was divided into eight sessions with
40 lectures and about 20 poster presentations by young scientists. A splendid
opening by Albert Eschenmoser
(Z(rich, Switzerland, and La Jolla, CA,
USA) addressed the question of why
nature selected the structures of DNA
and RNA from a plethora of structurally
and functionally conceivable alternatives that a grand master of organic
chemistry is able to realize by design and
synthesis. According to Eschenmoser
the postulate of prebiotic robustness
deserves a serious reconsideration, at
least when it comes to the development
of new chemistry that aims to take
advantage of a higher level of systems
dynamics.
The session continued with an overview of the COST working group “Etiology, Replication, and Persistence of
RNA” given by Marie-Christine Maurel
(Paris, France) followed by workgroup
highlight presentations from John
Sutherland (Manchester, UK) on potentially prebiotic formation and reactions
of activated nucleotides and from
Michael G>bel (Frankfurt, Germany)
on the prospects and limitations of nonenzymatic oligomerization of ribonu-
cleotides. The unifying theme of the
session was genetic biomolecules and
their possible ancestors, such as peptide
nucleic acids (PNAs) as introduced and
discussed by Peter Nielsen (Copenhagen, Denmark). The afternoon saw
contributions on a remarkably efficient
template-directed synthesis of polynucleotides in artic ice (Christof Biebricher,
G>ttingen, Germany), twin ribozymes
(Sabine M(ller, Bochum, Germany),
and the role of boric acid as a prebiotic
catalyst of peptide formation (Benoit
Prieur, Paris, France). The Los Alamos
Protocell Project was introduced by
Hans Ziok (Los Alamos, NM, USA)
and Arvydas Tamulis (Vilnius, Lithuania). The closing lecture of the first day
was delivered by Zbigniew Zagorski
(Warsaw, Poland), who discussed considerations on the unprobability of panspermia.
The spontaneous generation of
homochirality, which is a signature of
life, was the subject of theoretical
research for a long time until Kenso
Soai (Tokyo, Japan) came up with the
first example of a chiral-symmetrybreaking reaction almost 15 years ago
in the style of the Frank model (1953);
for a recent example, see Scheme 1.[1]
Much impressive work has been elaborated since then including the kinetic
study by Donna Blackmond (London,
UK) which shows that chiral amplification is a second-order reaction with
respect to the chiral autocatalyst. As a
consequence of the latter, the Soai
reaction follows a hyperbolic growth
law that holds many promises for the
discovery of unusual spatiotemporal
patterns, whose design may be a future
subject of systems chemistry. Chiral-
Scheme 1. One aspect of systems chemistry: the origin of chirality.
2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2006, 45, 342 – 344
Angewandte
Chemie
symmetry-breaking processes may, however, also involve crystallization processes, a point that was clarified by Meir
Lahav (Rehovot, Israel) before he introduced the COST workgroup on “The
Use of Surfaces and Vesicles for the
Amplification of Homochirality in Polypeptide Chains”. Ben Feringa (Groningen, Netherlands), a key contributor to
this workgroup, presented a variety of
experimental systems which showed
that the question of breaking chiral
symmetry has many facets, ranging
from molecular motors to materials
nanotechnology.
The second half of the proceedings
on the second day was dedicated to the
issue of self-reproduction of protocells.
Tadashi Sugawara (Tokyo, Japan) gave a
brilliant keynote lecture about a continuously self-reproducing giant vesicle
system in which a bipolar amphiphile
(membrane precursor) sustains the
autocatalytic growth of giant multilamellar vesicles (GMVs). This precursor
is hydrolyzed to a membrane molecule
and a division-inducing agent. The originator of this field of research is PierLuigi Luisi (Rome, Italy), whose COST
workgroup on “Functionalized SelfReproducing Vesicles as Precursors for
Early Cells” was highlighted by experimental contributions from Christiano
Chiarabelli and Pasquale Stano (both
Rome). The theory behind vesicle selfreproduction, explaining observable
geometrical distortions of vesicle
shape, was outlined in the lecture by
Saša Svetina (Ljubljana, Slovenia) and
put forward by Doron Lancet (Rehovot,
Israel). His “lipid world” scenario
claims that compositional information
encoded in lipid mixtures which express
different catalytic phenotypes may be
the subject of a primitive way of evolution.
Vesicular models of early cells was
the subject of the morning session on the
third day opened by Antonio Lazcano
(Mexico City) who reconsidered early
stages of lipid biosynthesis in evolutionary history. Following an overview of the
workgroup by Vesna N>thig-Laslo
(Zagreb, Croatia), Constantinos Paleos
(Athens, Greece) presented his work on
the interaction of liposomes equipped
with complementary functional groups
as models for cellular aggregation. The
richness of lipid nanoscale phases and
Angew. Chem. Int. Ed. 2006, 45, 342 – 344
their dependence on pH as well as lipid
composition was introduced by Peter
Walde (Z(rich, Switzerland), who raised
the question about potentially primordial lipid structures and the range of
conditions for vesicle formation. How
vesicles could have exhibited the influence of a template for the formation of
peptides from thioglutamic acid was the
subject of a model study by Helmut
Zepik (Z(rich). A somehow similar
study, namely, the role of surfaces and
particles as organizational templates for
the formation of lipid bilayers, was
presented by Martin Hanczyc (Venice,
Italy).
“Chembiogenesis: A Meteoritic Perspective” was the title of the keynote
lecture given by Sandra Pizzarello
(Tempe, AZ, USA) to open the afternoon session. Interestingly, the Soai
reaction has found an application in
the amplification of chirality in the low
enantiomeric excesses from non-proteinogenic amino aids observed in meteorites. The workgroup on “Dynamic
Coevolution of Peptides and Chemical
Energetics, A Gate towards the Emergence of Homochirality and Nucleotides” was introduced by Laurent Boiteau
(Montpellier, France) and followed by a
contribution on the polymerization of
LeuchsG anhydride by Hans Kricheldorf
(Hamburg, Germany). The utilization of
the latter anhydride for the aminoacylation of nucleotides was highlighted by
Alastair L. Parkes (Manchester, UK) as
a prebiotic model of tRNA loading.
Theoretical contributions in this workgroup came from Tom Lenaerts (Brussels, Belgium) and Jean Claude Micheau
(Toulouse, France), who presented an
alternative mechanistic interpretation
for the autocatalysis in the Soai reaction.
Whereas in BlackmondGs kinetic investigations the Soai reaction was found to
be second order with respect to the
homochiral autocatalyst, Micheau reinterpreted the kinetic data using a model
that is based on the conventional interpretation of nonlinear effects caused by
a strong association in heterochiral
complexes. This model, however, contradicts NMR studies according to
which homo- and heterochiral complexes are nearly equally populated.
The lively discussions between Blackmond, Micheau, Soai, von Kiedrowski,
Szathmary, Lahav, and Schuster on
these matters continued in the Systems
Chemistry Workshop and contributed
very much to the style and spirit of both
meetings.
The keynote lecture by Peter Schuster (Vienna, Austria), on the fourth day
of the meeting, on the evolutionary
dynamics of RNA folding included an
impressive visualization of the influence
of mutations on the secondary structure
of RNA. In a similar spirit, Peter F.
Stadler (Leipzig, Germany) introduced
the work carried out by the workgroup
on “Emergence and Selection of Networks of Catalytic Species”. Mauro
Santos (Barcelona, Spain) presented
recent work with E>rs SzathmHry
(Budapest, Hungary) on a possible resolution of the error catastrophe paradox, which is based on EigenGs insight
that the error rate of replication must be
smaller than the inverse genome size.
The resolution is found in real ribozyme
structures, in which not each position
has the same probability for a deleterious mutation. SzathmHry summarized
his reflections on the integration of
metabolic subsystems into minimal
cells and the problems concerning systems integration that had to be solved in
order to achieve its goal. The session
was completed by Peter Strazewski
(Lyon, France) with a provocative
reconsideration of the enthalpy–entropy
compensation problem. His concept of
group thermodynamics and his insight
that both quantities, enthalpy and
entropy, are fundamentally linked by a
mathematical function that describes a
hyperbolic paraboloid may open a new
point of view in the future.
The afternoon session on the last day
began with a keynote lecture by Reza
Ghadiri (La Jolla, CA, USA) that summarized remarkable success at the frontier of self-replicating peptides and selforganizing catalytic networks by
employing peptides. The synthesis of
dynamic networks as signal-processing
entities was outlined and will certainly
be an issue of design that a field such as
systems chemistry is able to address in
the future. Synthesis was also the theme
of the lecture by Dieter Schinzer (Magdeburg, Germany), who revealed the
fascination in the hunt for the total
synthesis of a million-dollar drug. Both
epothilones and sorangicins still are
such candidates in the race between
2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org
343
Meeting Reviews
laboratories that are focused on the
synthesis of natural products.
The Systems Chemistry Workshop
provided two further days of exciting
brainstorming dedicated to creating
links between the groups of researchers
who are interested in template selfreplication, asymmetric autocatalysis,
vesicle self-reproduction, and protocell
formation. The main speakers focused
their lectures, giving insight into unpublished results and future perspectives.
This was particularly evident in the
lecture given by Albert Eschenmoser
which made clear that his published
studies on the aetiology of nucleic acid
structure are just the tip of an iceberg.
So many new informational oligomers
await to be discovered in the future.
As a result of the workshop, two
facets of systems chemistry were established. First, it can be understood in
terms of the integration of kinetic studies, dynamic modeling, structural studies, and computational chemistry to
obtain a better understanding of complex dynamic phenomena such as chemical self-replication and chiral-symmetry
breaking. The second facet can be seen
in the integration of dynamic subsystems into higher ordered supersystems
such as protocells. Systems chemistry
deals with complex dynamic phenomena
such as chemical self-replication and
chiral-symmetry breaking as well as
with the integration of dynamic subsystems into higher ordered supersystems.
344
www.angewandte.org
vesicles, and the Soai
Steen
Rasmussen
reaction is clearly a
(Los Alomos, NM, Systems chemistry
challenge. For example,
USA) reported on new
deals with complex
the coupling of temexperimental findings
plated self-replication
towards the implemen- dynamic phenomena
and vesicle self-reprotation of the Los such as chemical selfduction may be achievAlamos protocell. E>rs replication and chiralable if the templateSzathmHry and Timoteo symmetry breaking as
directed synthesis proCarlotti (Namur, Belwell as with the inteceeds with the liberagium)
reconsidered
tion of a lipid leaving
another scheme of sub- gration of dynamic
system integration that subsystems into higher group. Other opportunities as outlined by
is based on the chemo- ordered supersystems.
Szathmary are seen in
ton theory of Tibor
the coupling of self-repGanti.
lication and chromatogSurprising dynamic
self-organization processes leading to a raphy processes. The Soai reaction is
non-Brownian motion of self-reproduc- expected to exhibit interesting spatioing vesicles as well as the spontaneous temporal pattern formation such as
formation of helical mesophases were traveling or spiral waves. An experidiscussed by Tadashi Sugawara. These mental approach towards LancetGs lipid
phenomena go clearly beyond a ther- world is clearly feasible today and calls
modynamic description by lipid phase for suitable experimental systems. The
diagrams, as beautifully outlined by same holds for an experimental implePeter Walde. The experimental aspect mentation of GantiGs chemoton (a
was covered by Peter Strazewski, talking supersystem composed of a metabolic,
about peptidyl RNAs from lipophilic a genetic, and a compartment-forming
peptides, and Ludovic Jullien (Paris, subsystem), which may start from a
France), who gave an introduction on systematic investigation of couplings
the engineering of dynamic properties in between two subsystems. All this could
chemical systems with examples from be the future of systems chemistry.
his laboratory.
In a final discussion, von Kiedrowski [1] T. Kawasaki, M. Sato, S. Ishiguro, T.
outlined where the future of systems
Saito, Y. Morishita, I. Sato, H. Nishino,
chemistry may lie. The creation of
Y. Inoue, K. Soai, J. Am. Chem. Soc. 2005,
127, 3274 – 3275.
coupled autocatalytic systems starting
from well-characterized subsystems,
such as self-replicating templates and DOI: 10.1002/anie.200504139
2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2006, 45, 342 – 344
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