1. Department of Chemistry, Portland State University, Portland, Oregon 97201, United States
2. Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon 97239, United States
3. Department of Veterans Affairs Medical Center, Portland, Oregon 97239, United States
4. Experimental Therapeutics Branch, CIDR, Walter Reed Army Institute of Research, Silver Spring, Maryland 20910, United States