1. Department of Civil, Environmental, and Architectural Engineering, University of Kansas, Lawrence, KS 66045, USA.
2. Biochemical Research Service Laboratory, University of Kansas, Lawrence, KS 66045, USA.
3. Mass Spectrometry Laboratory, University of Kansas, Lawrence, KS 66045, USA.
4. Department of Chemistry, University of Kansas, Lawrence, KS 66045, USA.
5. Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011, USA.