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Origin of genetic material: looking for the ancestral cradle Enzo Gallori Department of Physics and Astronomy University of Florence, Italy Oparin 2014,

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Presentation on theme: "Origin of genetic material: looking for the ancestral cradle Enzo Gallori Department of Physics and Astronomy University of Florence, Italy Oparin 2014,"— Presentation transcript:

1 Origin of genetic material: looking for the ancestral cradle Enzo Gallori Department of Physics and Astronomy University of Florence, Italy Oparin 2014, Moscow, September

2 “On ne connaît pas complètement une science tant qu'on n'en sait pas l'histoire.” (To understand a science, it is necessary to know its history.) A. Comte

3 A LEXANDER I. O PARIN (1894–1980) “Proiskhozhdenie zhizny” 1924 “The Origin of Life” 1938

4 W HAT WAS THE PRIMORDIAL HABITAT OF LIFE ?

5 C HARLES D ARWIN ( ) “… But if (and oh what a big if!) we could conceive in some warm little pond with all sorts of ammonia & phosphoric salts,—light, heat, electricity &c present, that a protein compound was chemically formed, ready to undergo still more complex changes, …” Letter to J. D. Hooker, 1 Feb 1871

6 E RWIN S CHRÖDINGER “What is Life?” (1944)

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8 T HE B ASIC P RINCIPLE OF B IOLOGY Replication TranscriptionTranslation

9 “…Current biology indicates that life could have not evolved in the absence of a genetic replicating mechanism…” A. Lazcano, OLEB (2010) ↓ The presence of a genetic system is absolutely essential

10 M OLECULAR E VOLUTION Formation of Earth 4.5 Prebiotic chemistry 4.0 First DNA / protein life 3.5 Diversification of life 3.0 The “appearance” of a nucleic acid-like polymer able to evolve marks the beginning of life

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12 B UILDING C ODE 1. Synthesis and accumulation of precursors (i.e. nucleotides) 2. Polymerization of precursors. 3. Protection from degradation 4. Expression of “biological”potentiality of the information molecule

13 E ARLY A TMOSPHERE (?) Composition H 2 O, CO 2, N 2, NH 3, CH 4 Origin Volcanic outgassing

14 C LASSICAL RESEARCH : A QUEOUS S OLUTION C HEMISTRY A.I. Oparin (~1924) - J.B.S. Haldane (~1930) “The Primordial Soup”

15 S TANLEY M ILLER (1953)

16 Classical research: aqueous solution chemistry (primordial oceans) In these conditions: hydrolysis and not polymerization!

17 T HE “RNA W ORLD ”

18 J OHN D. B ERNAL ( )

19 T HE “C LAY H ONEYCOMB ” “… Clays and other minerals were necessary to: 1) Concentrate the organics present in a dilute ocean by adsorption 2) Protect these organics from destruction by U.V. light 3) Catalyze the polymerization of adsorbed organics…” J.D. Bernal (1951)

20 O RIGIN OF C LAY M INERALS Clay minerals originated by weathering of volcanic glass and rocks. The Mars investigation indicates the occurrence of clay minerals with an age of ≥ 3.5 Ga. By analogy, clay minerals would have formed on the early Earth.

21 C LAY ON M ARS

22 Role of Minerals, mainly Clay Minerals, in the synthesis of: → Nucleic Acid Bases Saladino et al., CHEMBIOCHEM (2004), Costanzo et al., BMC Evolutionary Biology (2007), Saladino et al., Physics Life Reviews (2012) → Stabilization of Ribose Ricardo et al., Science (2004)

23 J AMES F ERRIS

24 Clay minerals catalyze the formation of oligonucleotides up to 50-mer long Ertem and Ferris, Nature (1996); Ferris et al., Nature (1996) Ertem, OLEB (2004) A C T G T C C

25 Oligomerization of Nucleotides on Montmorillonite Mathew & Luthey-Schulten, OLEB (2010)

26 P ROTECTION OF N UCLEIC A CIDS DNA molecules adsorbed on clay minerals are protected to some extent against the action of different degrading agents, still maintaing their biological activities Stotzky & Gallori, Molecular Microbial Ecology, (1996)

27 B IOLOGICAL C HARACTERISTICS OF N UCLEIC A CID -C LAY C OMPLEXES DNA bound on clay is still able to transform bacterial competent cells Gallori et al., FEMS Microbiol Ecol (1994) DNA adsorbed on clay can be replicated and amplified by PCR Vettori et al., FEMS Microbiol Ecol (1996) Replication TAQ-Polymerase + Trasformation +

28 E LECTRON M ICROSCOPY (T.E.M.) K-Chromosomal DNA (X 154,000) K-Plasmid DNA (X 271,500) Franchi et al., OLEB (1999)

29 X-R AY A NALYSIS OF M-N UCLEIC ACID COMPLEXES Franchi et al., OLEB (1999)

30 B-Form A-Form Franchi et al., OLEB (1999) FT-IR A NALYSIS OF M-N UCLEIC A CID COMPLEXES

31 R OLE OF C ATIONS IN THE A DSORPTION Franchi, Ferris and Gallori, OLEB (2003)

32 E FFECTS OF UV AND X- RAYS RADIATION U.V. radiation DNA adsorbed on clay minerals is protected from both UV and X-ray radiation Ciaravella et al., Astrobiology (2004); Scappini et al., Astrobiology (2004)

33 E XPERIMENTS ON BOARD I NTERNATIONAL S PACE S TATION (ISS) Free and clay-adsorbed DNA in space environment (16-30/05/2011) De Sio et al., Microgravity Sci Technol (2012)

34 RNA-C LAY C OMPLEXES Clay minerals:  montmorillonite (M)  kaolinite (K) ssRNA Viroid Hammerhead Ribozyme RNA-Clay Complexes 16S RNA

35 A NNEALING OF C OMPLEMENTARY S INGLE S TRANDED N UCLEIC A CIDS A A A A A A A A U U U U G G G GA A A C C C C Franchi and Gallori, Gene (2005)

36 E NZYMATIC R EPLICATION OF C LAY -A DSORBED RNA Franchi and Gallori, Gene (2005)

37 Hammerhead Ribozymes Hairpin Ribozymes Could Clay-RNA Complexes Perform Enzymatic Reaction??

38 H AMMERHEAD R IBOZYME A VOCADO S UNBLOTCH V IROID (ASBVd) (F LORES, 1994)

39 A DENINE D EPENDENT H AIRPIN R IBOZYME (ADHR1) ADHR1 Meli et al., J. Biol. Chem (2003)

40 I NTERACTIONS OF RIBOZYMES WITH CLAY PARTICLES Tightly adsorbed RNA molecules are able: To perform self-cleavage reactions To resist to the action of various degradative agents (biotic and abiotic) Franchi & Gallori, Gene (2005); Biondi et al., Gene (2007)

41 Control + Mont Control in water UV in water UV + Mont ADHR1 SELF - CLEAVAGE KINETICS AFTER 5’ OF UV- IRRADIATION Biondi et al., BMC Evolutionary Biology (2007)

42 Phosphate (from apatite) N-Base Ribose

43 RADIATION ProtectionInteractionEvolution

44 C LAY M ICELLE

45 P ROMETHEUS ( Προμηθεύς, “ THE ONE WHO THINK OVER ”)

46 Prof. J. P. Ferris, Department of Chemistry and Chemical Biology, New York Center for Studies on the Origins of Life Prof. R. Flores, Universidad Politecnica Valencia, Spain Prof. M.-C. Maurel, Centre des Acides Nucléiques et Biophotonique, UPMC Paris VI, Paris, France Prof. G. Stotzky, Department of Biology, New York University, USA

47 T HANK YOU M ISHA !

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49 Real Mineral Structure Implementation of the theoretical model with a well defined spatial environment (i.e. a porous structure) Increase of information capacity of replicators in a mineral structured environment Results E VOLUTION ON “M INERAL H ONEYCOMB ” Branciamore et al., J Molec Evol (2010) Model


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