nai

Project Reports

• Computational Chemical Modeling the Link Between Structure and Reactivity of Iron-Sulfur Motifs

  The Fe-S mineral catalysis, Fe-S enzyme catalysis, and a biomimetic thrust areas of ABRC have their own unique ways to probe the relationships between structure and reactivity at the active sites of iron-sulfur enzymes and the structure and reactivity of iron-sulfur minerals. We have developed a cohesive link among these thrust areas through bridging the enzymatic/mineral catalysis and molecular structure/chemical reactivity by computational chemistry.

  ROADMAP OBJECTIVES: 3.1 3.2 3.3 7.1 7.2

• Origin of Life and Catalysis – Philosophical Considerations

  Our goal is to provide a solid philosophical foundation for the ABRC research program. To achieve this goal, we have several sub-goals like helping the students to develop their position as a group regarding a viable account for the metabolism-first theory, examining some methodological assumptions of the current astrobiological community, and finally propagating the information learned in our group to a larger community by offering courses on the origin of life.

  ROADMAP OBJECTIVES: 3.1 3.2 3.3 3.4 4.2

• Probing the Structure and Nitrogen Reduction Activity of Iron-Sulfur Minerals

  Fe-S compounds are common in both biological and geological systems. The adaptation of Fe-S clusters from the abiotic world to the biological world may have been an early event in the development of life on Earth and possibly a common feature of life elsewhere in the universe. The Iron-sulfur mineral thrust of the ABRC is focused on examining the structure and reactivity of FeS minerals using nitrogen fixation as a model reaction.

  ROADMAP OBJECTIVES: 3.1 3.2 3.3 3.4 7.1 7.2

• Structure, Function, and Biosynthesis of the Complex Iron-Sulfur Clusters at the Active Sites of Nitrogenases and Hydrogenases

  Iron-sulfur clusters are thought to be among the most ancient cofactors in living systems. The Fe-S enzyme thrust is focused on examining the structure, mechanism, and biosynthesis of the complex Fe-S enzymes nitrogenase and hydrogenase.

  ROADMAP OBJECTIVES: 3.1 3.2 3.3 7.1 7.2

• Biomimetic Cluster Synthesis: Bridging the Structure and Reactivity of Biotic and Abiotic Iron-Sulfur Motifs

  Synthetic approaches are being utilized to bridge the gap between Fe-S minerals and highly evolved biological Fe-S metalloenzymes. These studies are focusing on organic template (protein) mediated cluster assembly (biomineralization), probing properties of synthetic clusters, both as homogeneous and heterogeneous catalysts, investigating the impact of size scale on the properties of synthetic Fe-S clusters, and computational modeling of the structure and catalytic properties of synthetic Fe-S nanoparticles in the 5-50 nm range.

  ROADMAP OBJECTIVES: 3.1 3.2 3.3 3.4 7.1 7.2

• Molecular Beam Studies of Nitrogen Reactions on Iron-Sulfur Surfaces

  It is generally accepted that surface-mediated reactions occur on defect sites. The role of defects in the formation of ammonia is being evaluated using molecular beam-surface scattering experiments in which a deuterium atom plasma source is used to hydrogenate a pyrite surface with D atoms. The hydrogenated surface is subsequently bombarded with a molecular beam of energetic N2 molecules and the conversion of N2 to products such as ammonia is probed through mass spectrometry.

  ROADMAP OBJECTIVES: 3.1 3.2 3.3 7.1 7.2