For Fulbright Presentation March 11 or 13, 2002

Title:Study of the GTP-binding and association of the Escherichia coli signal recognition particle (Ffh*4.5S RNA) and its receptor (FtsY)

Abstract:Signal recognition particle (SRP) proteins are GTP-binding proteins necessary for proper export/transport of secretory and plasma membrane proteins. Failure of this system results in diseases such as cystic fibrosis. Understanding the SRP is, therefore, the subject of intensive medical research as this transport system is a potential target for drug design. The structures of various GTP/Mg²⁺-binding (NG) domain proteins without GTP/Mg²⁺ for both the SRP (Ffh) and SRP (FtsY) receptor proteins from human cells and from various bacteria have been solved using x-ray crystallography by other scientists. There is a crystal structure available of FtsY without GTP/Mg²⁺ from Escherichia coli. Using the available structures, I am modeling Ffh from E. coli bacteria using available computational programs. The SRP system in E. coli bacteria is much simpler than that found in humans and thus makes a good model for study and hopefully for understanding the human SRP system. Models of GTP/Mg²⁺ bound forms of both proteins and an active complex between these two proteins bound GTP/Mg²⁺ and the required 4.5 S RNA will be presented. This modeled active complex should prove useful in understanding how the components of the SRP interact to transport other proteins within and out of the cell.