1. Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, 881 Madison Avenue, Memphis, Tennessee 38163, United States
2. Laboratory of Microbiology, Institute of Microbial Chemistry (BIKAKEN), 3-14-23, Kamiosaki, Shinagawa-ku, Tokyo 141-0021, Japan
3. Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E. California Boulevard, Pasadena, California 91125, United States