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II. La chimie des modèles

II. La chimie des modèles. Biomimétisme vs. bioinspirée. Biomimétisme. Biomimétisme vs. bioinspirée. Bioinspiré. IIa. La chimie de la vie.

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II. La chimie des modèles

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  1. II. La chimie des modèles

  2. Biomimétisme vs. bioinspirée Biomimétisme

  3. Biomimétisme vs. bioinspirée Bioinspiré

  4. IIa. La chimie de la vie

  5. « We not only want to know how Nature is (and how her transactions are carried through), but we also want to reach, if possible, a goal which may seem utopian and presumptuous, namely, to know why Nature is such and not otherwise. » Albert Einstein in Festschrift für Aurel Stodola,E. Honegger, Ed. (Orell Füssli, Zürich, 1929).

  6. « … duplex structure appears to violate many of the rules that chemists might themselves use to design molecular recognition systems. For example, the double helix appears to disregard Coulomb’s law. Cations bind anions, and anion bind cations. In DNA, however, a polyanion binds another polyanion. One might think (and indeed, many have thought) that the duplex would be more stable if one strand were uncharged, or polycationic. Likewise, chemists often exploit rigidity when designing receptors to fit ligands. DNA strands are floppy. One would think (and many have thought) that conformationally rigid DNA analogues should be better at molecular recognition. Another curious feature of the DNA duplex is its use of hydrogen bonding to achieve specificity. This would not be the chemist’s preference in water, where hydrogen bonding to solvent competes with interstrand hydrogen bonding. Indeed, several groups have sought to dispense with hydrogen bonding between nucleobases entirely. » Steven A. Benner Acc. Chem. Res. 2004, 37, 784 La structure en double hélice de l’ADN violerait-elleles lois élémentaires de la chimie?

  7. 5’ T A 3’ C G G C A T 3’ 5’ ADN, 3 éléments indispensables?

  8. Peut-on changer les bases nucléïques?

  9. Cinq nouveaux appariements possibles

  10. Pyrimidine > pyridine ~ pyrazine

  11. 5’--CACN1ACTTTCTCCT-3’3’-TGTGN2TGAAAGAGG--5’ Vers un alphabet génétique artificiel ArtificiallyExpandedGeneticInformationSystem (AEGIS)

  12. Pu-py appariements 3 2 1

  13. 3 2 1 Py-py appariements 5O°C

  14. 2 Pu-pu appariements 5O°C

  15. Peut-on changer les bases nucléïques? Réponse : oui du point de vue de la chimie Du point de vue de la biologie, la question est de savoir si la Nature acceptera de nouvelles nucléobases. « Ligases, kinases, and other workhorses of molecular biology accept AEGIS components. So does the ribosome. In a collaboration with James Bain and Richard Chamberlin at the University of California at Irvine, we challenged the ribosome from Escherichia coli to translate a mRNA containing a 65th codon built using AEGIS components and synthesize a protein with a 21st amino acid. When given a charged tRNA carrying the anticodon incorporating the appropriate AEGIS complement, a nonstandard peptide was synthesized. This study also showed how release factors work in natural systems to terminate translation. Steven A. Benner Acc. Chem. Res. 2004, 37, à paraître Le problème à résoudre est la polymérase

  16. 10.7 Å 12.9 Å A four-base paired genetic helix with expanded sizeH. Liu, J. Ga, S. R. Lynch, D. Saito, L. Maynard and E. T. KoolScience2003, 302, 868-871.

  17. d(xATxAxATxATTxAT) d(AxTAAxTAxTxTAxT) d(xAxTxAxAxTxAxTxTxAxT) Stabilité du duplex Contrôle : d(ATAATATTAT)

  18. Artificial metallo-DNA: a bio-inspired approach to metal array programmingM. Shionoya and K. TanakaCurrent Opinion in Chemical Biology2004, sous presse.

  19. Augmentation de la diversité

  20. Augmentation de la diversité…

  21. Vers de futur matériaux

  22. La structure en hélice est respectée…

  23. Peut-on changer les liens phosphate? Sulfone-linked RNAs permettent des appariements de type Watson-Crick pour des courtes séquences mais pas avec de longues séquences (agrégation). La répétition de charge sur le squelette de l’ADN semble être de nature universelle.

  24. 1’,2’-seco-ADN homo-ADN Reconnu par DNA et RNA pol. Peut-on changerle ribose? Structure des oligonucléotides complètement différentes

  25. Chimie pré-biotique

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