Nick Lane, a renowned British biochemist and professor at University College London, dives into the mysteries surrounding the origin of life. He discusses the pivotal role of the Krebs cycle, not just in energy production but also in understanding life's beginnings. Lane explores how metabolic processes may predate genetics, linking energy flow to the emergence of life. Intriguingly, he connects these concepts to contemporary health issues like cancer, emphasizing the profound implications of energy and chemistry in the evolution of living organisms.
Proto cells can form membranes that allow for autotrophic growth from inorganic gases and potential structure formation.
RNA in autotrophic protocells can template peptides and enhance proton transport, leading to the development of more complex functions.
The Krebs cycle is responsible for amino acid production, playing a crucial role in various biological processes and contributing to the evolution of larger, more complex eukaryotic cells through endosymbiosis.
Deep dives
Autotrophic protocells driven by inorganic gradients
Proto cells can form membranes made of fatty acids and iron-sulfur clusters bound by cysteine, allowing for the segregation of different phases and the potential for autotrophic growth from inorganic gases.
Integration of RNA into autotrophic protocells
RNA can be introduced into autotrophic protocells and it can potentially template peptides that can interact with membranes or bind ions like magnesium, improving growth and potentially forming structures similar to enzymatic active sites.
Transition to RNA world
RNA could have emerged in autotrophic protocells and improved protocell growth by templating peptides and enhancing proton transport or ion binding, leading to the development of more complex functions.
Potential for genetic code emergence
The physical interaction between nucleotides and amino acids in the genetic code suggests the possibility of improved growth and structure formation in autotrophic protocells, providing a pathway for the emergence of a primitive genetic code.
The Krebs cycle's role in making amino acids
The Krebs cycle is not only responsible for shuffling energy around but also for making amino acids. By replacing one oxygen with ammonia, a Krebs cycle intermediate can be transformed into an amino acid. This process occurs quickly and efficiently, allowing for the production of amino acids through a simple step. These amino acids, with their physical properties and ability to interact with other molecules, play a crucial role in various biological processes.
The significance of mitochondria and the complex origin of eukaryotic cells
Mitochondria, once independent bacteria, play a vital role in cellular energy generation through the Krebs cycle. The incorporation of these bacteria into host cells led to a significant change in cell structure and function. The process of endosymbiosis allowed for the internalization of energy production and the development of larger, more complex eukaryotic cells. This cellular transformation, which likely occurred due to a population of cells snuggling up to each other and engaging in mutual trade, marked a crucial step in the evolution of life on Earth.
The origin of life here on Earth was an important and fascinating event, but it was also a long time ago and hasn’t left many pieces of direct evidence concerning what actually happened. One set of clues we have comes from processes in current living organisms, especially those processes that seem extremely common. The Krebs cycle, the sequence of reactions that functions as a pathway for energy distribution in aerobic organisms, is such an example. I talk with biochemist about the importance of the Krebs cycle to contemporary biology, as well as its possible significance in understanding the origin of life.
Nick Lane received his PhD from the Royal Free Hospital Medical School. He is currently a professor of Evolutionary Biochemistry at University College London. He was a founding member of the UCL Consortium for Mitochondrial Research, and is Co-Director of the UCL Centre for Life’s Origin and Evolution. He was awarded the 2009 UCL Provost’s Venture Research Prize, the 2011 BMC Research Award for Genetics, Genomics, Bioinformatics and Evolution, the 2015 Biochemical Society Award, and the 2016 Royal Society Michael Faraday Prize and Lecture. His new book is Transformer: The Deep Chemistry of Life and Death.