3:45 PM - 4:00 PM
[MIS02-06] Abiotic synthesis of metal-sulfur clusters containing iron and molybdenum and evaluation of their catalytic functions
Keywords:Chemical evolution, Iron-sulfur cluster, Metalloprotein
The chemical evolution is a widely accepted theory describing the origin of life on Earth. However, the specific reaction pathways and catalysts of the chemical evolution are still controversial. Extant life uses metalloproteins with clusters consisting of metal and sulfur atoms as their active centers, as catalysts for a variety of biochemical reactions in metabolic systems [1]. Metal-sulfur clusters ligated by small compounds are predicted to have played a catalytic role in chemical evolution [2]. There are however only few reports of chemical reactions catalyzed by metal-sulfur clusters in the context of chemical evolution (e.g., [3]) and among the reactions reported, iron-sulfur clusters are predominantly used. It is unclear how metal-sulfur clusters containing metals other than iron could contribute to chemical evolution as catalysts. Herein, this study aims to experimentally evaluate the role of metal-sulfur clusters in chemical evolution processes on the early Earth. This study is focused on the iron-sulfur clusters and iron-molybdenum-sulfur clusters, which are the active centers of ferredoxin [4] and nitrogenase [5], respectively. We examined whether metal-sulfur clusters containing iron and molybdenum could be synthesized abiotically and whether they also exhibit a catalytic function.
Ferric chloride, ferrous chloride, ammonium tetrathiomolybdate, and sodium sulfide were used as metal and sulfur sources, and glutathione and 2-mercaptoethanol were used as ligands. Reacting these compounds yielded UV-visible absorption spectra akin to 4Fe4S clusters. These preliminary results suggests that metal-sulfur clusters containing iron and molybdenum might have been synthesized abiotically. The addition of anthraquinone-2-sulfonate, used here as a redox indicator, suggests that some of the mixed metal-sulfur clusters could be involved in redox reactions. It is currently investigated whether these cluster species could facilitate the reduction of organic compounds.
Reference
[1] J. Winkler & H. Gray, Chem. Rev. 114, 3369-3380 (2014)
[2] L. Belmonte & S. Mansy, Elements 12, 413-418 (2016)
[3] C.Bonfio, et al., Nat. Catal. 1, 616-623 (2018)
[4] P. Venkateswara Rao & R. Holm, Chem. Rev. 104, 527-559 (2004)
[5] C. Van Stappen, et al., Chem. Rev. 120, 5005-5081 (2020)
Ferric chloride, ferrous chloride, ammonium tetrathiomolybdate, and sodium sulfide were used as metal and sulfur sources, and glutathione and 2-mercaptoethanol were used as ligands. Reacting these compounds yielded UV-visible absorption spectra akin to 4Fe4S clusters. These preliminary results suggests that metal-sulfur clusters containing iron and molybdenum might have been synthesized abiotically. The addition of anthraquinone-2-sulfonate, used here as a redox indicator, suggests that some of the mixed metal-sulfur clusters could be involved in redox reactions. It is currently investigated whether these cluster species could facilitate the reduction of organic compounds.
Reference
[1] J. Winkler & H. Gray, Chem. Rev. 114, 3369-3380 (2014)
[2] L. Belmonte & S. Mansy, Elements 12, 413-418 (2016)
[3] C.Bonfio, et al., Nat. Catal. 1, 616-623 (2018)
[4] P. Venkateswara Rao & R. Holm, Chem. Rev. 104, 527-559 (2004)
[5] C. Van Stappen, et al., Chem. Rev. 120, 5005-5081 (2020)