1. Department of Microbial Pathogenesis, Boyer Center for Molecular Medicine, Yale School of Medicine, New Haven, Connecticut 06536;, , , , ,
2. Howard Hughes Medical Institute, Boyer Center for Molecular Medicine, Yale School of Medicine, New Haven, Connecticut 06536
3. Yale Microbial Diversity Institute, West Haven, Connecticut 06516
4. Department of Genetic Engineering, College of Life Sciences, Kyung Hee University, Yongin 446-701, South Korea