UCSC Emeriti Lecture, Nov 13, 2008
Music Recital Hall, UCSC, 7pm
"What is Life? What was Life? What will Life Be?"
David Deamer, Department of Chemistry and Biochemistry, UC Santa Cruz
In 1944, the physicist and Nobelist Erwin Schrödinger published a book with the title "What is Life?" Schrödinger stated on the first page of his book that he would address a fundamental question: "How can the events in space and time which take place within the spatial boundary of a living organism be accounted for by physics and chemistry?” That remains an open question more than sixty years later, but we have learned so much more about the history of life on the Earth that we can ask a related question: “What was Life?” Because several research groups are attempting to fabricate synthetic life in the laboratory, we can also ask “What will Life be?”
As scientists addressed these questions over the past decade, a remarkable connection began to emerge between our understanding of life on the Earth and the stellar processes that give rise to solar systems with habitable planets. In order to support research on this connection, NASA decided to initiate a new scientific program called astrobiology. One of the goals of astrobiology is to discover how life originated on our planet and whether it exists beyond the Earth. To get some idea of the scope of this question, consider for a moment what a planetary surface in our solar system was like four billion years ago, before life began. The surfaces of the Earth and Mars were hot, mostly covered by salty oceans containing a dilute solution of thousands of organic compounds. Volcanic land masses emerged from boiling seas, and tidal wet-dry cycles occurred daily where sea met land. Water continuously evaporated from the interface between sea and atmosphere, condensed as rain and fell on the volcanic islands where it formed small pools containing organic solutes. From this unpromising chaos of land, sea and atmosphere, the first life somehow emerged, certainly on the Earth, perhaps on Mars.
My research associates and I have been studying self-assembly processes in natural geothermal environments and related laboratory simulations that simulate what the Earth was like before life began. We can be reasonably confident that liquid water was required, together with a source of organic compounds and energy to drive polymerization reactions. The clue that we are following is that certain molecules have properties that allow them to assemble into more complex structures, a familiar example being the way that soap molecules can self-assemble into the spherical structures we call soap bubbles. The same chemical and physical properties allow lipid molecules to assemble into the membranous compartments of living cells. In earlier work we observed that macromolecules such as nucleic acids and proteins are readily encapsulated in membranous boundaries during wet-dry cycles such as those that would occur at the edges of geothermal springs or tide pools. The resulting structures are referred to as protocells, in that they exhibit certain properties of living cells and are models of the kinds of encapsulated macromolecular systems that would have led toward the first forms of cellular life. In my talk, I will show how self-assembly of certain molecules in membranous compartments was likely to be involved in the origin of life. I will also describe recent progress we and others have made toward fabricating synthetic cells in the laboratory.
About Professor Deamer
David W. Deamer is a Research Professor in the Department of Biomolecular Engineering and Department of Chemistry and Biochemistry at the University of California, Santa Cruz. His undergraduate degree was in Chemistry, at Duke University, Durham NC, and his Ph.D. in Physiological Chemistry from the Ohio State University School of Medicine. Following post-doctoral research at UC Berkeley, he joined the faculty at UC Davis in 1967, then moved his laboratory to UC Santa Cruz in 1994.
Prof. Deamer's research interest is how cellular life arose on the Earth nearly four billion years ago. He has investigated meteorites that contain organic carbon compounds, and demonstrated self-assembly of complex lipid-protein structures that exhibit some of the properties of life. Prof. Deamer is in the process of writing a book on the origin of life that will be published by UC Press.
A second research area concerns DNA transport through nanoscopic pores in membranes. This work focuses on developing an instrument that can analyze nucleic acids as individual molecules.