1. School of Chemistry and Biochemistry Georgia Institute of Technology 901 Atlantic Drive Atlanta GA 30332 USA
2. Present Address: Skaggs School of Pharmacy and Pharmaceutical Sciences University of California at San Diego 9500 Gilman Drive La Jolla CA 92037 USA
3. Center for Microbial Dynamics and Infections Georgia Institute of Technology 311 Ferst Drive Atlanta GA 30332 USA
4. School of Biological Sciences Georgia Institute of Technology 950 Atlantic Drive Atlanta GA 30332 USA