1. Department of Molecular Biology and The Center for Mass Spectrometry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, Mass Consortium Corporation, San Diego, California 92109, Department of Chemistry, George Washington University, Washington, DC 20052, and Nanosys, Inc., 2625 Hanover Street, Palo Alto, California 94304