1. Department of Medicine, Sungkyunkwan University School of Medicine, Samsung Medical Center, Molecular Therapy Research Center, and Samsung Biomedical Research Institute, Seoul 135-710, South Korea
2. Department of Medicine, Chungnam National University, Daejeon 301-040, South Korea
3. Department of Medicine, Sungkyunkwan University School of Medicine, Samsung Medical Center, Molecular Therapy Research Center, and Samsung Biomedical Research Institute, Seoul 135-710, South Korea
4. Department of Chemistry, Seoul National University, Seoul 151-742, South Korea
5. Kyunghee University, Graduate School of East-West Medicine, Seoul 130-050, South Korea
6. Institute of Molecular Biology and Genetics, Seoul National University, Seoul 151-742, South Korea.