1. Department of Biotechnology, Tokyo University of Agriculture and Technology, 2-24-16, Nakacho, Koganei, Tokyo 184-8588, Japan, National Institute for Material Science, 3-13 Sakura, Tsukuba, Ibaraki 305-0003, Japan, Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank Sheffield S10 2TN, U.K.