A Combinatoric ApproachA Combinatoric Approachto the Study of Mineral-to the Study of Mineral-Molecule Interactions Molecule Interactions

A Combinatoric ApproachA Combinatoric Approachto the Study of Mineral-to the Study of Mineral-Molecule Interactions Molecule Interactions

Frontiers in Mineral Science 2007Frontiers in Mineral Science 2007Session A15: Mineral-Molecule InteractionsSession A15: Mineral-Molecule Interactions

June 28, 2007June 28, 2007Robert Hazen, Geophysical LaboratoryRobert Hazen, Geophysical Laboratory

Research CollaboratorsResearch CollaboratorsResearch CollaboratorsResearch CollaboratorsCarnegie Institution Hugh Churchill Jim Cleaves George Cody Gözen Ertem Tim Filley Rebecca Martin Jake Maule Andrew SteeleGeorge Washington Univ. Glenn Goodfriend Henry TengUniversity of Colorado Gifford Miller Steven DeVogel

University of Arizona Robert T. DownsGeorge Mason University Harold MorowitzJohns Hopkins University Dimitri Sverjensky Carnegie-Mellon University Aravind Asthagiri David ShollSmithsonian Institution Tim Gooding Detlef Rost Ed VicenziSpanish Astrobiology Inst. Antonio Salgado-Serrano

Research CollaboratorsResearch CollaboratorsResearch CollaboratorsResearch CollaboratorsCarnegie Institution Hugh Churchill Jim Cleaves Jim Cleaves George Cody Gözen Ertem Tim Filley Rebecca MartinRebecca Martin Jake MauleJake Maule Andrew SteeleAndrew SteeleGeorge Washington Univ. Glenn Goodfriend Henry TengUniversity of Colorado Gifford Miller Steven DeVogel

University of Arizona Robert T. DownsGeorge Mason University Harold MorowitzJohns Hopkins University Dimitri Sverjensky Dimitri Sverjensky Carnegie-Mellon University Aravind AsthagiriAravind Asthagiri David ShollSmithsonian Institution Tim Gooding Detlef Rost Ed VicenziEd VicenziSpanish Astrobiology Inst. Antonio Salgado-Serrano

Two QuestionsTwo Questions(Possibly Related)(Possibly Related)

Two QuestionsTwo Questions(Possibly Related)(Possibly Related)

2. What processes selected life’s idiosyncratic molecules?

1. How do crystals interact with organic molecules?

Origin of Biomolecules: The Problem

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?

Biomolecular Selectivity:Biomolecular Selectivity:Amino AcidsAmino Acids

Biomolecular Selectivity:Biomolecular Selectivity:Amino AcidsAmino Acids

• Only 20 biological amino Only 20 biological amino acids compared to >90 in acids compared to >90 in Murchison meteoriteMurchison meteorite

• Only Only -H amino acids (i.e., -H amino acids (i.e., no no -methyl amino acids) -methyl amino acids)

• Homochirality – L >> RHomochirality – L >> R

Biological HomochiralityBiological HomochiralityBiological HomochiralityBiological HomochiralityMany of life’s essential molecules are chiral.Many of life’s essential molecules are chiral.

42

C

3

1

(L)-enantiomer(L)-enantiomer

42

C

3

1

(R)-enantiomer(R)-enantiomer

How did life on Earth become homochiral?How did life on Earth become homochiral?

Annual sales of chiral pharmaceuticals Annual sales of chiral pharmaceuticals approaches $200 billion.approaches $200 billion.

Our Hypothesis: Minerals WorkOur Hypothesis: Minerals WorkOur Hypothesis: Minerals WorkOur Hypothesis: Minerals Work

Our Hypothesis: Minerals WorkOur Hypothesis: Minerals WorkOur Hypothesis: Minerals WorkOur Hypothesis: Minerals Work

Aspartic acid on calcite

Lysine on quartz

TCA on calcite

TCA on feldspar

Quartz – SiO2Quartz – SiO2

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!

Quartz: Face-Specific AdsorptionQuartz: Face-Specific Adsorption

(10-11)

(01-11)

Quartz Crystal FacesQuartz Crystal Faces

Courtesy of S. ParkerCourtesy of S. Parker

Quartz – (100) FaceQuartz – (100) Face

Quartz – (101) FaceQuartz – (101) FaceQuartz – (101) FaceQuartz – (101) Face

MIRRORMIRROR

Quartz – (011) FaceQuartz – (011) FaceQuartz – (011) FaceQuartz – (011) Face

Feldspar (110)Feldspar (110)Feldspar (110)Feldspar (110)

Feldspar (110)Feldspar (110)Feldspar (110)Feldspar (110)

Diopside – (110) FaceDiopside – (110) FaceDiopside – (110) FaceDiopside – (110) Face

Diopside – (110) FaceDiopside – (110) FaceDiopside – (110) FaceDiopside – (110) Face

Calcite – CaCOCalcite – CaCO33Calcite – CaCOCalcite – CaCO33

Calcite – (214) FaceCalcite – (214) FaceCalcite – (214) FaceCalcite – (214) Face

Modeling Mineral-Molecule InteractionsModeling Mineral-Molecule InteractionsModeling Mineral-Molecule InteractionsModeling Mineral-Molecule Interactions

Begin by bringing a D-alanine molecule close to an unrelaxed calcite (214) surface.

initial final H

N

C

O

Ca

initial final H

N

C

O

Ca

D-Alanine-Calcite (214) InteractionsD-Alanine-Calcite (214) InteractionsD-Alanine-Calcite (214) InteractionsD-Alanine-Calcite (214) Interactions

The stable converged configuration reveals surface relaxation and Ca-O and O-H

interactions, but no strong third interaction.

initial final H

N

C

O

Ca

initial final H

N

C

O

Ca

Alanine-Calcite (214) InteractionsAlanine-Calcite (214) InteractionsAlanine-Calcite (214) InteractionsAlanine-Calcite (214) Interactions

D-alanineD-alanine L-alanineL-alanine

(D)-ASP (L)-ASP

The most stable configuration found for D- and L-The most stable configuration found for D- and L-aspartic acid on calcite (214) surface. The D aspartic acid on calcite (214) surface. The D

enantiomer is favored by 8 Kcal/mol. enantiomer is favored by 8 Kcal/mol.

Aspartic Acid-Calcite (214) Aspartic Acid-Calcite (214) InteractionsInteractions

Aspartic Acid-Calcite (214) Aspartic Acid-Calcite (214) InteractionsInteractions

A General Research StrategyA General Research StrategyA General Research StrategyA General Research Strategy

How do we evaluate interactions among

the numerous possible mineral-molecule

pairs?

We need a combinatoric approach.

Jake Maule, Andrew Steele and Rebecca Martin

A Combinatoric StrategyA Combinatoric StrategyA Combinatoric StrategyA Combinatoric Strategy

ChipWriter

• Up to 126 minerals

• Up to 49,152 spots per

mineral

• Up to 96 different wells

• 100-micron spots

A B CMicroarrays 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 557-592nm

(Cy3) and 650-690nm (Cy5). Each image shows the intensity of Cy3/Cy5 fluorescent bands at a focal distance of 60m (left) and 120m (right).

Selective Adsorption on MineralsSelective Adsorption on MineralsSelective Adsorption on MineralsSelective Adsorption on Minerals

ChipReaderChipReader• Simultaneous analysesSimultaneous analyses of 10of 1055 spots. spots.• D/L amino acid resolutionD/L amino acid resolution• Excitation wavelengths atExcitation wavelengths at 532 and 635 nm532 and 635 nm

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

A B

Tagged Lysine on QuartzTagged 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:

Edward Vicenzi and Detlef RostToF-SIMS Lab, Smithsonian Institution

Feldspar (010) in ToF-SIMS Sample Holder

ToF-SIMS

High-resolution ion fragment maps of

150-micron L-lysine spots on calcite (214).

X

X

mass / u42.85 42.90 42.95 43.00 43.05 43.10 43.15

010

110

210

310

410

510

Inte

nsity

mass / u20 40 60 80 100 120 140 160 180 200 220 240 260 280

010

110

210

310

410

510

610

710

Inte

nsity

43Ca+ 42CaH+

C2H3O+

C2H5N+

C3H7+

L lysinecalcite

m/m ~ 8000 FWHM

300 AMU L-Lysine on Calcite (214)

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

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

D-Lysine on Feldspar (010)

DL-Xylose on Feldspar (010)

mass / u42.85 42.90 42.95 43.00 43.05 43.10 43.15 43.20

010

110

210

310

410

510

Inte

nsi

ty

C2H5N (43.04)

C2H3O (43.02)

Key to Adsorbants----- arabinose

----- lyxose

----- ribose

----- xylose

----- lysine

Mass vs. Intensity for ~43 mass unit fragments

PentoseSugars

Amino Acid

CONCLUSIONSCONCLUSIONS

• 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.

With thanks to:

NASA Astrobiology Institute National Science Foundation

Carnegie Institution of Washington