1. Division of Structural Biochemistry, Department of Biochemistry, Jichi Medical University, Tochigi 321-0498, Japan
2. Division of Functional Biochemistry, Department of Biochemistry, Jichi Medical University, Tochigi 321-0498, Japan
3. Center for Experimental Medicine, Jichi Medical University, Tochigi 321-0498, Japan
4. Department of Agriculture, Kyushu University, Fukuoka 819-0395, Japan