Affiliation: | Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544-1014,1. Microbiology and Molecular Genetics and Biotechnology and Bioengineering Center, Medical College of Wisconsin, Milwaukee, Wisconsin 53226,2. Laboratory of Cellular and Structural Biology,3. Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, Rockefeller University, New York, New York 100214. |