Speaker: Paul Falkowski, Rutgers University

Title: Light to Life: The origin of metabolic catalysis

Abstract: Solar radiation is the overwhelming source of energy for life on Earth. How and when photosynthetic reactions evolved is not known a gap of ca. 1 billion years. However, prebiotic photochemical reactions of transition metal bearing minerals early in Earth’s history led to the sacrificial production of H2 by populating antibonding orbitals.  These reactions, which involve Fe and Mn carbonates, appear to have been critical to the evolution of biologically catalyzed processes that ultimately formed a planetary network of coupled electron transfers far from thermodynamic equilibrium.  Using a novel approach, based primarily on protein structure, we have discovered that the origin of metabolism arose from only two protein folds.  That analysis has allowed us to "reverse engineer" ultra small peptides/proteins that catalyze electron transfer reactions.  For example, we have designed an 8 amino acid peptide that binds Ni and functions as an hydrogenase. Our goal is to understand the origin, evolution, of autocatalytic reactions that led to the planetary electron transfer network.