Third Annual Maria Goeppart-Mayer Symposium at SDSC Discusses Information Transfer in Chemical Systems

Information transfer in chemical systems was the general theme for the third annual Maria Goeppart-Mayer symposium, organized by Kim Baldridge of SDSC and sponsored by the SDSC on the UC San Diego campus March 7. This event showcases scientists working in many scientific disciplines and was supported by the local section of the American Chemical Society and donations from local industry including Ligand Pharmaceuticals and Isis Pharmaceuticals.

Plenary speakers for the 1998 symposium were Joan Heller-Brown of UC San Diego's Department of Pharmacology, Robin Garrell of UCLA's Department of Chemistry, Marye-Anne Fox from the Department of Chemistry at the University of Texas at Austin, and Brenda Baker of Isis Pharmaceuticals. The event honors Maria Goeppart-Mayer, who shared the 1963 Nobel Prize for Chemistry while a member of the UC San Diego Physics Department.

The day kicked-off with Joan Heller-Brown's lecture on g-proteins and the signal transduction phenomenon. She discussed the ways in which information can be passed from outside to inside the cell by chemical messengers that affect the structure and function of membrane-spanning proteins (g-proteins). In turn, these proteins release new chemical messengers into the cell and there by regulate cell function in response to external signals. The number and type of signals and function are enormous, but Heller-Brown illustrated the principles of this biochemical phenomenon with a few key examples from her laboratory.

Robin Garrell added a materials chemistry flavor to the symposium with her lecture on the properties and characterizations of "self-assembled" monolayers (SAMs). The affinity of gold atoms for negatively charged groups like sulfides and sulfur oxides is the basis for a method to make a single-layer of carbon-based molecules stick to a gold surface. The carbon chains or cycles have been specially prepared to contain the sulfur groups that stick to gold. The carbon "tails" line up, pointing away from the surface in a regular manner to form an ordered array of molecules. Garrell showed how these SAMs have potential applications in sensor technologies. Given an appropriate carbon scaffolding and electrical connections to the gold, chemical information about the solution can be transmitted through the SAM and read electrochemically.

Electrochemically based information transfer was precisely the topic of the next lecture by Marye Anne Fox. She focused on the ways in which electron flow could be mediated by the chemical environment. In particular, the helical structure of certain amino acid chains creates an effective electric field (dipole moment) over the length of the helix, such that one end is more negative and the other is more positive. Fox showed, in an elegant series of experiments, that electron transfer could occur in one direction more easily than the other along such a helix. This difference in electron transfer potential proved a more general principle dictating how electrons will move. She then applied this principle to electron transfer through SAMs, concentrating on a chemical property called fluorescence—the relesae of light from an energetically excited molecule. Monitoring the fluorescence allowed her to understand better the electrochemistry of SAMs.

The genic code is the information source from biological function, and the intricate interactions of DNA, RNA, and the ribosome form the transfer machinery that turns the code into functioning proteins. Blocking this information transfer at the source DNA was the topic of Brenda Baker, the last speaker. At Isis Pharmaceuticals, the goal has been to develop mock pieces of nucleic acids that can bind to DNA and thereby inhibit the transfer of the message to RNA. This strategy, known as anti-sense technology, is the basis for a prototypical therapy for gene-related illnesses. Far from the clinic, Baker showed how this biochemical method could be implemented in the test tube and then developed for in vivo studies.

A combination luncheon and poster session followed the morning plenary presentations. More than two dozen posters from several southern California institutions, including Caltech, UCLA, UC San Diego, San Diego State University, the University of San Diego, and California State University at Northridge, were on display. Topics ranged from the physics of carbon clusters (fullerenes) to confocal microscopy.

Again this year the symposium lived up to its reputation for excellence in science in the model set down by Goeppert-Mayer herself. Baldridge, who founded and continues to organize the annual event, already has begun plans for the fourth annual symposium. Information on past meetings, the life of Goeppert-Mayer, and future programs can be accessed on the Web.
Copyright 1997 SDSCwire.