1. NIH, Division of Computer Research and Technology, 5/405, Bethesda, Maryland 20892, St. Petersburg Nuclear Physics Institute, Gatchina, 188350 Russia, ONR Europe, 223 Old Marylebone Road, London NW1 5TH, U.K., Institute of Biotechnology, Yerevan, Armenia 375056, and NIST, Biotechnology Division, 222/A353, Gaithersburg, Maryland 20899