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Introduction

The Astrobiology Biogeocatalysis Research Center (ABRC) at Montana State University focuses on the abiotic chemical interconversions that result in the formation of the raw materials or reactants necessary for various condensation reactions that result in the formation of the basic building blocks for life. The ABRC’s efforts are focused on laying the fundamental groundwork for Goal 3 (Origins of Life) of the NASA Astrobiology Roadmap.

Research Plan – The ABRC is focused on addressing and integrating the following challenges in unraveling biological and mineral catalysis:

1. Detailed studies on biological Fe-S catalysts. In order to evaluate the connection among Fe-S-based catalysis in minerals, clusters, and biocatalysts, we propose to investigate

• Biological mechanisms for Fe-S cluster synthesis and assembly, including the introduction of cluster modifications and their role in radical chemistry.
• Structural and physical characterization of complex Fe-S cluster-containing enzymes.
• Homogeneous (solution) catalytic properties of Fe-S cluster enzymes.
• Spectroscopic and computational analyses of Fe-S clusters in selected enzymes (nitrogenase, hydrogenase)

2. Investigation of catalysis at iron-sulfide mineral surfaces in aqueous and gas phase systems as models of prebiotic chemical transformations. Foci will include

• Properties of synthetic mineralized surfaces
• The impact of surface defects and modifications on the physical and catalytic properties of an iron-sulfur mineral surface
• The effect of energy (photo, redox, thermal, mechanical), pH, concentration, partial pressure of gases, surface area, and length scale on the structural, physical, and catalytic properties of iron-sulfur clusters, particles and minerals, and materials studied by beam/surface collision experiments.
• Spectroscopic analyses and structural modeling of mineral surface defects by integrated DFT/MO/MM method.

3. Using nanomaterials to bridge the gap between Fe-S minerals and highly evolved biological Fe-S metalloenzymes.

• Organic template (protein) mediated cluster assembly – biomineralization.
• Properties of synthetic nanoclusters, both as homogeneous and heterogeneous catalysts.
• The impact of size scale on the properties of synthetic iron-sulfur clusters and array.
• Computational modeling of the structure and catalytic properties of synthetic iron-sulfur nanoparticles in the 5-50 nm range.