UCSDの新しい研究が、生命の起源の可能性に光を当てる(New Research from UC San Diego Sheds Light on the Possible Origins of Life)


機能的なプレバイオティック代謝の発見により、炭素捕捉技術の向上が期待される Discovery of functional prebiotic metabolism shows promise for improving carbon-capture technologies

2023-05-18 カリフォルニア大学サンディエゴ校(UCSD)

◆この研究のリードサイエンティストであり、カリフォルニア大学サンディエゴ校ジェイコブス工学部のShu Chien-Gene Lay生物工学科のデータサイエンティストであるAmir Akbari氏は、「C1炭素技術の開発において、この研究から得られた数学モデルと計算ツールは有用であり、最小限の炭素フットプリントを持つ経済的なバイオマニュファクチャリングシステムの設計を可能にするでしょう」と述べています。この研究は、PNAS(米国科学アカデミー紀要)の2023年5月1日号に掲載されました。


生物学的細胞における代謝のホメオスタシスと成長 Metabolic homeostasis and growth in abiotic cells

Amir Akbari and Bernhard O. Palsson
Proceedings of the National Academy of Sciences  Published:May 1, 2023


Metabolism is believed to have emerged from ancient autotrophic pathways fueled by volcanic gases as carbon and energy sources. Variants of these pathways remain in modern autotrophs in the deepest branches of the tree of life. The energy metabolism of modern autotrophs resembles the geological interactions of H2 and CO2 in hydrothermal vents, pointing to a metabolic origin of biochemistry at the interface of the lithosphere and hydrosphere. Here, we demonstrate the feasibility of self-sustaining, self-amplifying CO2 fixation by H2 in hydrothermal pores using a first-principle approach that is consistent with physicochemical constraints and chemistry of prebiotic carbon fixation. We identify the conditions for the emergence of metabolism on the early Earth, revealing the fundamental nature of biological carbon fixation.


Metabolism constitutes the core chemistry of life. How it began on the early Earth and whether it had a cellular origin are still uncertain. A leading hypothesis for life’s origins postulates that metabolism arose from geochemical CO2-fixing pathways, driven by inorganic catalysts and energy sources, long before enzymes or genes existed. The acetyl-CoA pathway and the reductive tricarboxylic acid cycle are considered ancient reaction networks that hold relics of early carbon-fixing pathways. Although transition metals can promote many steps of these pathways, whether they form a functional metabolic network in abiotic cells has not been demonstrated. Here, we formulate a nonenzymatic carbon-fixing network from these pathways and determine its functional feasibility in abiotic cells by imposing fundamental physicochemical constraints. Using first principles, we show that abiotic cells can sustain a steady carbon-fixing cycle that performs a systemic function over a relatively narrow range of conditions. Furthermore, we find that in all feasible steady states, the operation of the cycle elevates the osmotic pressure, leading to volume expansion. These results suggest that achieving homeostatic metabolic states under prebiotic conditions was possible, but challenging, and volume growth was a fundamental property of early metabolism.