1. Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana 47405, United States
2. Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Miyagi, Japan
3. Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota 55455, United States
4. Laboratory for Biological Mass Spectrometry, Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States