Research conducted by the lab of University of California San Diego Professor of Chemistry and Biochemistry Neal Devaraj has shed light on the possible explanation for the origin of lipid membranes, crucial components for the development of early cells on Earth. The study, published in Nature Chemistry, explores how simple molecules such as short fatty acids could have evolved into the complex membranes necessary for life to thrive. The researchers focused on the reaction between two simple molecules, an amino acid called cysteine and a short-chain choline thioester, to understand how these early cell structures may have formed.
Life on Earth relies heavily on lipid membranes, which provide structure to cells and serve as a platform for various biological processes. These membranes are composed of long chains of fatty acids, but the challenge lies in understanding how these complex structures originated from the simple molecules present on Earth billions of years ago. While shorter chain fatty acids were abundant on early Earth, longer chain lengths are necessary to form vesicles, the compartments that house the internal machinery of a cell. The researchers aimed to uncover how these early protocell structures may have formed in the absence of enzymes, which did not exist over four billion years ago.
Using silica glass as a mineral catalyst, the researchers found that the reaction between cysteine and thioesters on the surface of the silica resulted in the formation of lipid membranes. These membranes were capable of generating protocell-like vesicles that could sustain biochemical reactions, offering a possible explanation for the emergence of life on Earth. This process occurred at lower concentrations than would be required in the absence of a catalyst, providing insight into how life could have evolved from simple molecules in a prebiotic Earth environment.
The research team’s goal was to understand how life could have emerged in the absence of pre-existing life, bridging the gap between nonliving matter and living organisms. By exploring the biochemical reactions involved in lipid membrane formation, they have provided a potential explanation for how early cell structures may have developed on Earth. The study sheds light on the complex processes that may have led to the evolution of life on our planet, offering new insights into the origin of cells and the membranes that make them possible.
The authors of the study included researchers from UC San Diego and UCLA, and the research was supported by funding from the National Science Foundation and the National Institutes of Health. By investigating the reactions between simple molecules and a mineral catalyst, the team has delved into the fundamental processes that may have driven the formation of lipid membranes and early cell structures. This research contributes to our understanding of the origin of life on Earth and the potential mechanisms that may have led to the development of complex organisms from simple molecular components.
