nai

Project Progress

Task 1. Proteomics (Fogel, Scott, Steele)

This spring Fogel’s group completed a flight on NASA Johnson Space Center’s (JSC’s) KC-135 to perform an immunological experiment at zero gravitiy. They are interested in developing antibody-antigen reactions for detecting signs of life on Mars and Europa. This flight was a first opportunity to see if the immune response worked well at zero or reduced Martian gravity, and how the fluids behaved in conventional biochemical assays. The Protein Chip reader will be used to provide ground truth to the protein assays determined by the microarray assay. Results were presented to a workshop held by Ciphergen, the company that builds the systems. The instrument needed several repairs in 2002, but it has been successfully repaired and is back in working order. It is clear from attending the meeting that we are the only group trying to use the technology for molecules other than straight proteins.

Shewanella was cultured at two different temperatures (30°C and 45°C) to study the induction of heat shock proteins and the effect of temperature on the proteome. A set of 26 proteins and peptides with molecular weights ranging from 980 to 132,000 daltons were detected in microbes grown at both temperatures. In the 30°C culture, 6 different proteins were measured that had molecular weights ranging from 8,000 to 20,000 daltons; conversely, in the 45°C culture, overall molecular weight ranges were substantially greater (116,000 to 225,000 daltons). Peaks corresponding to monomers, dimers, and trimers of heat shock proteins (GSP 90, GSP 70, and GSP 60) were detected in the 45°C culture. Protein Chip technology was able to distinguish rapidly the changes in the microbial proteome as environmental conditions fluctuated.