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Caltech

DIX Planetary Science Seminar

Tuesday, January 21, 2025
4:00pm to 5:00pm
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Arms 155 (Robert P. Sharp Lecture Hall)
Origin of Life's Homochirality: From Magnetic Minerals to a Homochiral Genome
Furkan Ozturk, Kavli-Laukien Fellow, Department of Physics, Harvard University,

Essential molecules of life are chiral; they exist in mirror-symmetrical pairs. However, biological systems exclusively use only one form of these pairs: right-handed sugars, along with left-handed amino acids. This phenomenon characterizes life as homochiral. The origins of this molecular asymmetry, however, remain elusive, and it is this long-standing mystery that I will address in my presentation. The chiral-induced spin selectivity (CISS) effect has established a strong coupling between electron spin and molecular chirality. This coupling paves the way for breaking the chiral molecular symmetry via spin-selective processes. Achiral magnetic surfaces, when spin-polarized, can function as chiral agents due to the CISS effect, serving as templates for the asymmetric crystallization of chiral molecules. We studied the spin-selective crystallization of racemic ribo-aminooxazoline (RAO), a central precursor of RNA and DNA, on magnetite surfaces—achieving homochirality in two crystallization steps. We also demonstrated the chirality-induced avalanche magnetization of magnetite by RAO molecules. Moreover, we studied the prebiotic synthesis and magnetic properties of magnetite minerals in fresh water lakes, providing a plausible environmental setting for our scenario. Finally, we proposed a pathway through which the achieved homochirality in a single chiral compound, RAO, can efficiently propagate throughout the entire prebiotic network—from D-nucleic acids to L-peptides and then to homochiral metabolites. Our findings provide a prebiotically plausible model for achieving systems-level homochirality from racemic starting materials and highlight the importance of magnetic minerals in addressing this age-old mystery.

For more information, please contact Abigail Keebler by email at akeebler@caltech.edu.