[1] Natl Inst Infect Dis, Dept Pathol, Shinjuku Ku, Tokyo 1628640, Japan
[2] Univ Tokushima, Inst Enzyme Res, Div Enzyme Chem, Tokushima 770, Japan
[3] Hokkaido Univ, Sch Med, Lab Mol & Cellular Pathol, Sapporo, Hokkaido 060, Japan
[4] CREST, JST, Sapporo, Hokkaido, Japan
[5] Natl Inst Neurol Disorders & Stroke, Cent Nervous Syst Studies Lab, NIH, Bethesda, MD USA