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A Combinatoric Approach to the Study of Mineral- Molecule Interactions A Combinatoric Approach to the Study of Mineral- Molecule Interactions Frontiers.

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Presentation on theme: "A Combinatoric Approach to the Study of Mineral- Molecule Interactions A Combinatoric Approach to the Study of Mineral- Molecule Interactions Frontiers."— Presentation transcript:

1 A Combinatoric Approach to the Study of Mineral- Molecule Interactions A Combinatoric Approach to the Study of Mineral- Molecule Interactions Frontiers in Mineral Science 2007 Session A15: Mineral-Molecule Interactions June 28, 2007 Robert Hazen, Geophysical Laboratory

2 Research Collaborators Carnegie Institution Hugh Churchill Jim Cleaves George Cody Gözen Ertem Tim Filley Rebecca Martin Jake Maule Andrew Steele George Washington Univ. Glenn Goodfriend Henry Teng University of Colorado Gifford Miller Steven DeVogel University of Arizona Robert T. Downs George Mason University Harold Morowitz Johns Hopkins University Dimitri Sverjensky Carnegie-Mellon University Aravind Asthagiri David Sholl Smithsonian Institution Tim Gooding Detlef Rost Ed Vicenzi Spanish Astrobiology Inst. Antonio Salgado-Serrano

3 Research Collaborators Carnegie Institution Hugh Churchill Jim Cleaves George Cody Gözen Ertem Tim Filley Rebecca Martin Jake Maule Jake Maule Andrew Steele Andrew Steele George Washington Univ. Glenn Goodfriend Henry Teng University of Colorado Gifford Miller Steven DeVogel University of Arizona Robert T. Downs George Mason University Harold Morowitz Johns Hopkins University Dimitri Sverjensky Carnegie-Mellon University Aravind Asthagiri David Sholl Smithsonian Institution Tim Gooding Detlef Rost Ed Vicenzi Spanish Astrobiology Inst. Antonio Salgado-Serrano

4 Two Questions (Possibly Related) 2. What processes selected life’s idiosyncratic molecules? 1. How do crystals interact with organic molecules?

5 Origin of Biomolecules: The Problem A fundamental attribute of life is a high degree of molecular selectivity and organization, but prebiotic synthesis processes are indiscriminate. What prebiotic processes might have contributed to such selection and organization?

6 Biomolecular Selectivity: Amino Acids Only 20 biological amino acids compared to >90 in Murchison meteorite Only 20 biological amino acids compared to >90 in Murchison meteorite Only  -H amino acids (i.e., no  -methyl amino acids) Only  -H amino acids (i.e., no  -methyl amino acids) Homochirality – L >> R Homochirality – L >> R

7 Biological Homochirality Many of life’s essential molecules are chiral. 4 2 C 3 1 (L)-enantiomer 4 2 C 3 1 (R)-enantiomer How did life on Earth become homochiral? Annual sales of chiral pharmaceuticals approaches $200 billion.

8 Our Hypothesis: Minerals Work

9 Aspartic acid on calcite Lysine on quartz TCA on calcite TCA on feldspar

10 Quartz – SiO 2 Quartz is the only common chiral rock-forming mineral Right Left Reports of successful chiral selections as early as the 1930s. Yet all previous authors used powdered quartz!

11 Quartz: Face-Specific Adsorption (10-11) (01-11)

12 Quartz Crystal Faces Courtesy of S. Parker

13 Quartz – (100) Face

14 Quartz – (101) Face MIRROR

15 Quartz – (011) Face

16 Feldspar (110)

17

18 Diopside – (110) Face

19

20 Calcite – CaCO 3

21 Calcite – (214) Face

22 Modeling Mineral-Molecule Interactions Begin by bringing a D-alanine molecule close to an unrelaxed calcite (214) surface.

23 D-Alanine-Calcite (214) Interactions The stable converged configuration reveals surface relaxation and Ca-O and O-H interactions, but no strong third interaction.

24 Alanine-Calcite (214) Interactions D-alanineL-alanine

25 (D)-ASP(L)-ASP The most stable configuration found for D- and L- aspartic acid on calcite (214) surface. The D enantiomer is favored by 8 Kcal/mol. Aspartic Acid-Calcite (214) Interactions

26 A General Research Strategy How do we evaluate interactions among the numerous possible mineral-molecule pairs? We need a combinatoric approach.

27 Jake Maule, Andrew Steele and Rebecca Martin

28 A Combinatoric Strategy ChipWriter Up to 126 minerals Up to 49,152 spots per mineral Up to 96 different wells 100-micron spots

29 A BC Microarrays of Cy3-labeled asparagine, glutamine and tyrosine on glass at 20 serial dilutions. Each microarray was scanned simultaneously with 532nm/635nm lasers and the fluorescence emission was captured at the wavelength bands of nm (Cy3) and nm (Cy5). Each image shows the intensity of Cy3/Cy5 fluorescent bands at a focal distance of 60  m (left) and 120  m (right).

30 Selective Adsorption on Minerals ChipReader Simultaneous analyses Simultaneous analyses of 10 5 spots. of 10 5 spots. D/L amino acid resolution D/L amino acid resolution Excitation wavelengths at Excitation wavelengths at 532 and 635 nm 532 and 635 nm

31 Microarrays of Cy3-labeled L-lysine on left- and right-handed quartz (100) faces at 8 serial dilutions. 150-micron spots. AB

32 Tagged Lysine on Quartz Most molecules of prebiotic interest are not fluorescent. Fluorescent tags significantly modify the adsorption behavior. Advances: We can print microarrays and observe differential adsorption on mineral surfaces. Problems:

33 Edward Vicenzi and Detlef Rost ToF-SIMS Lab, Smithsonian Institution

34 Feldspar (010) in ToF-SIMS Sample Holder

35 ToF-SIMS High-resolution ion fragment maps of 150-micron L-lysine spots on calcite (214). X X

36 43 Ca +42 CaH + C2H3O+C2H3O+ C2H5N+C2H5N+ C3H7+C3H7+ L lysine calcite m/  m ~ 8000 FWHM 300 AMU L-Lysine on Calcite (214)

37 9 x 13 Array on 1 x 1 x 0.3 cm feldspar plate.

38 AMINO ACIDS AND SUGARS ON FELDSPAR (010) Face – 1 x 1 cm plate

39 D-Lysine on Feldspar (010)

40 DL-Xylose on Feldspar (010)

41 Intensity C 2 H 5 N (43.04) C 2 H 3 O (43.02) Key to Adsorbants arabinose lyxose ribose xylose lysine Mass vs. Intensity for ~43 mass unit fragments Pentose Sugars Amino Acid

42 CONCLUSIONS Microarray technology coupled with ToF- SIMS provides a powerful experimental means for combinatoric studies of mineral- molecule interactions. Many mineral surfaces have the potential for chiral selection of plausible prebiotic molecules.

43 With thanks to: NASA Astrobiology Institute National Science Foundation Carnegie Institution of Washington


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