Affiliation: | aNational Creative Research Initiatives Center and School of Biological Sciences, Seoul National University, Seoul 151-742, Republic of Korea;bDepartment of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejon 305-701, Republic of Korea;cDepartment of Molecular Microbiology and Immunology, University of Southern California, CA 90033, USA;dInstitute of Molecular Biology and Genetics, Seoul National University, Seoul 151-742, Republic of Korea |