1. Seattle Biomedical Research Institute, Seattle, Washington 98109,
Mayo Proteomics Research Center, Department of Biochemistry and Molecular
Biology and Department of Obstetrics and Gynecology, Mayo Clinic College
of Medicine, Rochester, Minnesota 55905, and W.M. Keck FT-ICR Mass
Spectrometry Laboratory, Department of Chemistry, North Carolina State
University, Raleigh, North Carolina 27695