April 2, 2008
One of the prime directives in NASA's mission program is to deliver vehicles and instruments throughout the solar system to detect signs of life, past or present. This would be easiest if we believed that the life (or its remnants) that might be encountered had chemical similarities to the life that we know on Earth, either in their genetic molecules, their catalytic molecules, or their metabolisms. Recent experiments in the laboratory in the area of synthetic biology have identified many chemistries that, at least in principle, could support life, however. This means that our search for life should not be constrained by tools that would identify only the life that we know. This talk will discuss alternative molecular structures that might support alien life, what laboratory studies suggest that they might be plausible in alien life forms, the interplay between chance and necessity in the emergence of life, and how missions might be designed to not miss such "weird" life.
Steven A. Benner is a distinguished fellow at the Foundation for Applied Molecular Evolution in Gainesville, Florida. He has BS and MS degrees in Molecular Biophysics and Biochemistry from Yale University and a PhD in Chemistry from Harvard University. The Benner group has Initiated synthetic biology as a field. The Benner group was the first to synthesize a gene for an enzyme, and used organic synthesis to prepare the first artificial genetic systems. These systems have been used to direct the synthesis of artificial proteins having unnatural amino acids, in FDA-approved clinical assays for HIV, hepatitis B and hepatitis C that improves the medical care of over 400,000 patients annually, and to support the first artificial chemical system capable of Darwinian evolution. Benner's group invented dynamic combinatorial chemistry, combining ideas from molecular evolution, enzymology, analytical chemistry, and organic chemistry to generate a strategy to discover small molecule therapeutic leads. A German company, Alantos, is today using this technology to develop drug leads. The Benner group established paleomolecular biology, where researchers resurrect ancestral proteins from extinct organisms for study in the laboratory, The strategy allows scientists to connect chemistry to function in biology, which is defined by an organism's fitness in a complex and changing environment. The Benner group helped found evolutionary bioinformatics, in 1991, launched one of the first web-based bioinformatics servers with Gaston Gonnet, generated the first naturally organized protein sequence databases, and helped develop the MasterCatalog that generated ca. $4 million in sales. This work also supported the first exhaustive matching of a modern protein sequence database, the first convincing tools to predict structure in proteins from sequence data, strategies to detect distant homologs using structure prediction, and "post-genomic" tools to detect changing protein function. Steven Benner was a National Science Foundation Graduate Fellow, a Junior Fellow in the Harvard Society of Fellows, a Searle Scholar, 1984-86, a Sloan Foundation Fellow, 1984-86, a Townes R. Leigh Commemorative Professor, 1999. He received a Dreyfus Award for Young Faculty, 1982, an Anniversary Prize, Federation of European Biochemical Societies, 1993, a Nolan Summer Award, 1998, an Arun Gunthikonda Memorial Award, 1998, a B. R. Baker Award, 2001, and a Sigma Xi Senior Faculty Award 2005.