[1] Osaka Univ, Sch Med, Dept Physiol, Suita, Osaka 565, Japan
[2] Osaka Univ, Fac Engn Sci, Dept Biophys Engn, Toyonaka, Osaka 560, Japan
[3] JST, ERATO, Biomotron Project, Osaka 562, Japan
[4] Natl Inst Genet, Struct Biol Ctr, Mishima, Shizuoka 411, Japan