1. Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan, Antibiotics Laboratory, RIKEN Discovery Research Institute, Saitama 351-0198, Japan
2. Antibiotics Laboratory, RIKEN Discovery Research Institute, Saitama 351-0198, Japan
3. Antibiotics Laboratory, RIKEN Discovery Research Institute, Saitama 351-0198, Japan, Graduate School of Life and Environmental Sciences, University of Tsukuba, Ibaraki 305-8572, Japan
4. Pharmaceutical Research Laboratories, Nippon Kayaku Co., Ltd., Tokyo 115-8588, Japan
5. Department of Industrial Chemistry, Faculty of Engineering, Tokyo University of Science, Tokyo 162-8601, Japan