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P a r t i c i p a n t s :
Giovanna Costanzo, researcher; Fabiana Ciciriello, post-doc
fellow; Samanta Pino, PhD student; Silvia Lopizzo, collaborator.
C o l l a b o r a t i o n s :
Dipartimento di Agrobiologia e Agrochimica, Università della
Tuscia, Viterbo (Prof. Raffaele Saladino); Università di Roma
Tor Vergata, (Dr. Claudia Crestini); INAF, Osservatorio Astrofisico
di Arcetri, Firenze (Prof. John R. Brucato).
Report of activity
The general goal of our research is the determination
of a plausible and experimentally verifiable
ensemble of chemical processes allowing the spontaneous
organization of informational polymers in abiotic
conditions. Once identified, this system could
provide invaluable information both on the origin of
informational polymers and on the persistence capacity
of the human genetic system in terrean and nonterrean
environments.
In this frame of reference we are currently analyzing:
Synthesis of nucleic precursors
The reaction yielding nucleic bases from formamide
in the presence of catalysts but in the absence of any
biotic (cellular or enzymatic) effector is being carefully
analyzed. Previous analyses have determined
the syntheses from formamide and the catalysts: simple
metal oxides, olivines, titanium oxides, clays,
phosphate minerals, basalts, sulphur-containing minerals.
The analyses being currently performed pertain
to a series of zirconium-based minerals and a
large panel of boron-containing compounds. The
rationale for the first type of analyses is that zirconia
formed only in the presence of water. Given that zirconia
are the oldest minerals identified on Earth, the
syntheses of nucleic acids occurring in their presence
would be highly instructive on the relationship
“catalysts: water: nucleic bases”. The protective func-
Principal investigator: Ernesto Di Mauro
Professor of Molecular Biology
Dipartimento di Genetica e Biologia Molecolare
Tel: (+39) 06 49912880; Fax: (+39) 06 4440812
ernesto.dimauro@uniroma1.it
81
Molecular recognition in biomolecules - AREA 4
Spontaneous formation and evolution of informational
nucleic polymers
tion of borates of various kinds towards nucleosides
has been recently identified. Hence the interest of
the exploration of their synthetic capacity. The overall
analysis will provide a complete picture for the
syntheses of nucleic bases in the presence of the
mineral compounds which are major constituents of
the solar system.
The syntheses yielding acyclonucleosides are being
analyzed in mixed systems consisting of: [formamide
+ formaldehyde] as building material, and mixtures
of minerals as catalyst component. The reactions
are being performed in terrestrial conditions and will
be compared to similar reactions performed in spacewise
conditions.
Polymerizations and stability
Next step towards complexity is the activation by
phosphorylation of abiotically synthesized nucleosides.
This problem has been solved by our group, as
reported (Costanzo et al., J Biol Chem. 2007,
282:16729-35).
This observation has allowed us to answer the question:
may an ensemble of monomers give rise to
informational molecules endowed with pre-genetic
possibilities? We have previously determined the
physical-chemical conditions in which this may occur
(Saladino et al., J Biol Chem. 2005, 280:35658-69;
Saladino et al., J Biol Chem. 2006, 281:5790-6). A
recent set of analyses has determined the properties
of RNA molecules that allow the possibility of evolution
in abiotic environments and conditions. The
results are in (Ciciriello et al., Biochemistry 2008,
47:2732-42). Starting from these findings, we have
focused on the determination of the resilience properties
of nucleic polymers in terrestrial and spacewise
conditions. Namely, experiments are being conducted
to answer the questions:
- How does the structure of nucleic acids affect their
resistance to the hydrolytic process?
- Are cleavages in nucleic polymers being repaired
differently in low-gravity conditions?