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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. Research Collaborators. Carnegie Institution Hugh Churchill Jim Cleaves

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slide1

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

research collaborators
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

DimitriSverjensky

Carnegie-Mellon University

AravindAsthagiri

David Sholl

Smithsonian Institution

Tim Gooding

DetlefRost

Ed Vicenzi

Spanish Astrobiology Inst.

Antonio Salgado-Serrano

research collaborators1
Research Collaborators

Carnegie Institution

Hugh Churchill

Jim Cleaves

George Cody

GözenErtem

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

DimitriSverjensky

Carnegie-Mellon University

AravindAsthagiri

David Sholl

Smithsonian Institution

Tim Gooding

DetlefRost

Ed Vicenzi

Spanish Astrobiology Inst.

Antonio Salgado-Serrano

two questions possibly related
Two Questions(Possibly Related)

1. How do crystals interact with organic molecules?

2. What processes selected life’s idiosyncratic 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 amino acids
Biomolecular Selectivity:Amino Acids
  • Only 20 biological amino acids compared to >90 in Murchison meteorite
  • Only -H amino acids (i.e., no -methyl amino acids)
  • Homochirality – L >> R
biological homochirality

1

1

C

C

4

4

2

2

3

3

(L)-enantiomer

(R)-enantiomer

Biological Homochirality

Many of life’s essential molecules are chiral.

How did life on Earth become homochiral?

Annual sales of chiral pharmaceuticals

approaches $200 billion.

slide9

Our Hypothesis: Minerals Work

Aspartic acid on calcite

Lysine on quartz

TCA on calcite

TCA on feldspar

quartz sio 2
Quartz – 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 crystal faces
Quartz Crystal Faces

Courtesy of S. Parker

modeling mineral molecule interactions
Modeling Mineral-Molecule Interactions

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

d alanine calcite 214 interactions
D-Alanine-Calcite (214) Interactions

The stable converged configuration reveals surface relaxation and Ca-O and O-H interactions, but no strong third interaction.

slide25

Aspartic Acid-Calcite (214) Interactions

(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.

slide26

A General Research Strategy

How do we evaluate interactions among the numerous possible mineral-molecule pairs?

We need a combinatoric approach.

slide28

A Combinatoric Strategy

  • ChipWriter
  • Up to 126 minerals
  • Up to 49,152 spots per
  • mineral
  • Up to 96 different wells
  • 100-micron spots
slide29

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 557-592nm (Cy3) and 650-690nm (Cy5). Each image shows the intensity of Cy3/Cy5 fluorescent bands at a focal distance of 60mm (left) and 120mm (right).

A

B

C

slide30

Selective Adsorption on Minerals

  • ChipReader
  • Simultaneous analyses
  • of 105 spots.
  • D/L amino acid resolution
  • Excitation wavelengths at
  • 532 and 635 nm
slide31

A

B

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

tagged lysine on quartz
Tagged Lysine on Quartz

Advances:

We can print microarrays and observe differential adsorption on mineral surfaces.

Problems:

Fluorescent tags significantly modify the adsorption behavior.

Most molecules of prebiotic interest are not fluorescent.

slide33

Edward Vicenzi and Detlef Rost

ToF-SIMS Lab, Smithsonian Institution

slide35

ToF-SIMS

High-resolution ion fragment maps of

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

X

X

slide36

300 AMU

L lysine

calcite

C3H7+

C2H5N+

C2H3O+

43Ca+

42CaH+

m/Dm ~ 8000 FWHM

L-Lysine

on Calcite (214)

slide38

AMINO ACIDS AND SUGARS ON FELDSPAR

(010) Face – 1 x 1 cm plate

slide41

5

10

4

10

3

10

2

10

1

10

0

10

42.85

42.90

42.95

43.00

43.05

43.10

43.15

43.20

mass / u

Mass vs. Intensity

for ~43 mass unit fragments

C2H3O (43.02)

Key to Adsorbants

----- arabinose

----- lyxose

----- ribose

----- xylose

----- lysine

C2H5N (43.04)

Pentose

Sugars

Intensity

Amino Acid

conclusions
CONCLUSIONS
  • Many mineral surfaces have the potential for chiral selection of plausible prebiotic molecules.
  • Microarray technology coupled with ToF-SIMS provides a powerful experimental means for combinatoric studies of mineral-molecule interactions.
slide43

With thanks to:

NASA Astrobiology Institute

National Science Foundation

Carnegie Institution of Washington