[1] Russian Acad Sci, Lab Metab Modeling & Bioinformat, Pushchino 142292, Moscow Region, Russia
[2] GlaxoWellcome Med Res Ctr, Adv Technol & Informat Unit, Stevenage SG1 2NY, Herts, England
[3] Argonne Natl Lab, Div Math & Comp Sci, Argonne, IL 60439 USA